Oral neomycin inhibits the gastrointestinal absorption of penicillin V, oral vitamin B-12, methotrexate and 5-fluorouracil.


When used in therapeutic doses, azithromycin had a modest effect on the pharmacokinetics of atorvastatin, carbamazepine, cetirizine, didanosine, efavirenz, fluconazole, indinavir, midazolam, rifabutin, sildenafil, theophylline (intravenous and oral), triazolam, trimethoprim/sulfamethoxazole or zidovudine.


Patients receiving other narcotic analgesics, general anesthetics, phenothiazines, tranquilizers, sedative-hypnotics, tricyclic antidepressants or other CNS depressants (including alcohol) concomitantly with DILAUDID may exhibit an additive CNS depression.


- Lofexidine may enhance the CNS depressive effects of alcohol, barbiturates and other sedatives


The following are examples of substances that may reduce the blood-glucose-lowering effect of insulin: corticosteroids, danazol, diuretics, sympathomimetic agents (e.g., epinephrine, albuterol, terbutaline), isoniazid, phenothiazine derivatives, somatropin, thyroid hormones, estrogens, progestogens (e.g., in oral contraceptives).


Phenobarbital: Coadministration of felbamate with phenobarbital causes an increase in phenobarbital plasma concentrations, In 12 otherwise healthy male volunteers ingesting phenobarbital, the steady-state trough (Cmin) phenobarbital concentration was 14.2 micrograms/mL.


Levothyroxine Sodium Absorption: The following agents may bind and decrease absorption of levothyroxine sodium from the gastrointestinal tract: aluminum hydoxide, cholestyramine resin, colestipol hydrochloride, ferrous sulfate, sodium polystyrene sulfonate, soybean flour (e.g., infant formula), sucralfate.


H1 and H2 Blockers - Although not reported, L-histidine, via its metabolism to histamine, might decrease the efficacy of H1 and H2 blockers.


Diminished urinary excretion of norfloxacin has been reported during the concomitant administration of probenecid and norfloxacin.


Interactions may occur between EPA supplements and aspirin and other non-steroidal anti-inflammatory drugs and herbs such as garlic (Allium sativum) and ginkgo (Ginkgo biloba).


Immunosuppressive Drugs, Fibric Acid Derivatives, Niacin (Nicotinic Acid, Erythromycin, Azole Antifungals: Skeletal Muscle.


The response to Factrel may be blunted by phenothiazines and dopamine antagonists which cause a rise in prolactin.


The following are examples of substances that may reduce the blood-glucose-lowering effect: corticosteroids, niacin, danazol, diuretics, sympathomimetic agents (e.g., epinephrine, salbutamol, terbutaline), isoniazid, phenothiazine derivatives, somatropin, thyroid hormones, estrogens, progestogens (e.g., in oral contraceptives).


The possibility of hypotensive effects with PRINIVIL can be minimized by either discontinuing the diuretic or increasing the salt intake prior to initiation of treatment with PRINIVIL.


Consequently, the combination of methotrexate with acitretin is also contraindicated.


Human pharmacokinetic data indicate that oral ketoconazole markedly inhibits the metabolism of cisapride, resulting in a mean eight-fold increase in AUC of cisapride.


The anxiogenic effects of theophylline were reduced by pretreatment with CGS 21680, an A2-selective agonist, but not by N6-cyclopentyladenosine (CPA), an A1-selective agonist.


This study demonstrates that concurrent administration of thiosulfate permits at least a twofold increase in dose and total exposure to cisplatin.


The effects of nonbenzodiazepine agonists at benzodiazepine receptors, such as zopiclone, triazolopyridazines and others, are also blocked by ROMAZICON.


Co-administration of tacrolimus and bosentan resulted in markedly increased plasma concentrations of bosentan in animals.


Interactions with Other CNS Agents: Concurrent use of Levo-Dromoran with all central nervous system depressants (eg, alcohol, sedatives, hypnotics, other opioids, general anesthetics, barbiturates, tricyclic antidepressants, phenothiazines, tranquilizers, skeletal muscle relaxants and antihistamines) may result in additive central nervous system depressant effects.


Thus, when VIOXX and lithium are administered concurrently, subjects should be observed carefully for signs of lithium toxicity.


Plasma valproate concentration should be monitored when isoniazid and valproate are co administered, and appropriate dosage adjustments of valproate should be made.


Antibiotics (e.g., erythromycin, trimethoprim and sulfamethoxazole, amoxicillin).


Other drugs which may enhance the neuromuscular blocking action of nondepolarizing agents such as NUROMAX include certain antibiotics (e. g., aminoglycosides, tetracyclines, bacitracin, polymyxins, lincomycin, clindamycin, colistin, and sodium colistimethate), magnesium salts, lithium, local anesthetics, procainamide, and quinidine.


Thyroid Physiology: The following agents may alter thyroid hormone or TSH levels, generally by effects on thyroid hormone synthesis, secretion, distribution, metabolism, hormone action, or elimination, or altered TSH secretion: aminoglutethimide, p-aminosalicylic acid, amiodarone, androgens and related anabolic hormones, complex anions (thiocyanate, perchlorate, pertechnetate), antithyroid drugs, b-adrenergic blocking agents, carbamazepine, chloral hydrate, diazepam, dopamine and dopamine agonists, ethionamide, glucocorticoids, heparin, hepatic enzyme inducers, insulin, iodinated cholestographic agents, iodine-containing compounds, levodopa, lovastatin, lithium, 6-mercaptopurine, metoclopramide, mitotane, nitroprusside, phenobarbital, phenytoin, resorcinol, rifampin, somatostatin analogs, sulfonamides, sulfonylureas, thiazide diuretics.


Co-administration of lovastatin, atenolol, warfarin, furosemide, digoxin, celecoxib, hydrochlorothiazide, ramipril, valsartan, metformin and amlodipine did not result in clinically significant increases in aliskiren exposure.


Tell your doctor if you are taking any of the following drugs: blood thinners (Coumadin) other antidepressants metoprolol antihistamines carbamazepine (Tegretol) cimetidine (Tagamet) estrogens fluoxetine (Prozac) intraconazole (Sporanox) ketoconazole (Nizoral) levodopa lithium muscle relaxants birth control pills sleeping pills thyroid medications


Limited data in patients receiving known enzyme inducers ( phenytoin, phenobarbital, carbamazepine ) indicate only a 30% increase in the rate of flecainide elimination.


Tricyclic antidepressants (amitriptyline, imipramine, nortriptyline): Metabolism may be inhibited by combination hormonal contraceptives, increasing plasma levels of antidepressant;


Pharmacokinetic interaction between single oral doses of diltiazem and sirolimus in healthy volunteers.


Selective serotonin reuptake inhibitors (SSRIs) (e.g., fluoxetine, fluvoxamine, paroxetine, sertraline) have been reported, rarely, to cause weakness, hyperreflexia, and incoordination when coadministered with 5-HT1 agonists.


OBJECTIVES: To examine the effects of acute hydrocortisone pretreatment on the subjective and behavioral effects of d-amphetamine.


Thiazide Diuretics: The reports that the concomitant use of allopurinol and thiazide diuretics may contribute to the enhancement of allopurinol toxicity in some patients have been reviewed in an attempt to establish a cause-and-effect relationship and a mechanism of causation.


Valproate: Available data suggest that there is no significant effect of valproate on the clearance of Felbatol  at steady state, Therefore, the addition of valproate is not expected to cause a clinically important effect on Felbatol  (felbamate) plasma concentrations.


In studies in normal volunteers, there was no pharmacodynamic interaction between intravenous iloprost and either nifedipine, diltiazem, or captopril.


Coingestion of acetaminophen with theophylline, phenobarbital with acetaminophen, and valproic acid with phenobarbital at high to toxic concentrations decreases the binding of the target drug.


Amphotericin B injection and potassium-depleting agents: When corticosteroids are administered concomitantly with potassium-depleting agents (e.g., amphotericin B, diuretics), patients should be observed closely for development of hypokalemia.


Chlorotrianisene may interact with antidepressants, aspirin, barbiturates, bromocriptine, calcium supplements, corticosteroids, corticotropin, cyclosporine, dantrolene, nicotine, somatropin, tamoxifen, and warfarin.


Coadministration of valdecoxib and Ortho-Novum 1/35  increased the exposure of norethindrone and ethinyl estradiol by 20% and 34%, respectively.


When used in therapeutic doses, azithromycin had a modest effect on the pharmacokinetics of atorvastatin, carbamazepine, cetirizine, didanosine, efavirenz, fluconazole, indinavir, midazolam, rifabutin, sildenafil, theophylline (intravenous and oral), triazolam, trimethoprim/sulfamethoxazole or zidovudine.


Agents that have been found, or are expected to have decreased plasma levels in the presence of EQUETROTM due to induction of CYP enzymes are the following: Acetaminophen, alprazolam, amitriptyline, bupropion, buspirone, citalopram, clobazam, clonazepam, clozapine, cyclosporin, delavirdine, desipramine, diazepam, dicumarol, doxycycline, ethosuximide, felbamate, felodipine, glucocorticoids, haloperidol, itraconazole, lamotrigine, levothyroxine, lorazepam, methadone, midazolam, mirtazapine, nortriptyline, olanzapine, oral contraceptives(3), oxcarbazepine, Phenytoin(4), praziquantel, protease inhibitors, quetiapine, risperidone, theophylline, topiramate, tiagabine, tramadol, triazolam, valproate, warfarin(5) , ziprasidone, and zonisamide.


A 5-mg Vardenafil dose should not be exceeded when used in combination with 200 mg once daily ketoconazole.


CNS-Active Drugs Ethanol An additive effect on psychomotor performance was seen with coadministration of eszopiclone and ethanol 0.70 g/kg for up to 4 hours after ethanol administration.


Amphetamines may enhance the effects of tricyclic antidepressants.


Tetracyclines: Since both acitretin and tetracyclines can cause increased intracranial pressure, their combined use is contraindicated.


Amantadine, tricyclic antidepressants, and MAOIs may increase anticholinergic effect of clidinium.


Bentiromide may interact with acetaminophen (e.g., Tylenol), chloramphenicol (e.g., Chloromycetin), local anesthetics (e.g., benzocaine and lidocaine), para-aminobenzoic acid (PABA)-containing preparations (e.g., sunscreens and some multivitamins), procainamide (e.g., Pronestyl), sulfonamides (sulfa medicines), thiazide diuretics (use of these medicines during the test period will affect the test results), and pancreatic supplements (use of pancreatic supplements may give false test results).


Dopamine D2 receptor antagonists (e.g., phenothiazines, butyrophenones, risperidone) and isoniazid may reduce the therapeutic effects of levodopa.


Because of the possible additive effects of drugs that may depress the nervous system, ethanol or triazolam should be used cautiously in combination with tiagabine.


Anticonvulsants: In a pharmacokinetic study, maximum plasma concentrations of felodipine were considerably lower in epileptic patients on long-term anticonvulsant therapy (eg, phenytoin, carbamazepine, or phenobarbital) than in healthy volunteers.


Protease inhibitors: Amprenavir, lopinavir, nelfinavir, and ritonavir have been shown to decrease plasma levels of combination hormonal contraceptives;


Butalbital, acetaminophen and caffeine may enhance the effects of: other narcotic analgesics, alcohol, general anesthetics, tranquilizers such as chlordiazepoxide, sedative-hypnotics, or other CNS depressants, causing increased CNS depression.


Glyburide: The concomitant administration of ciprofloxacin with the sulfonylurea glyburide has, on rare occasions, resulted in severe hypoglycemia.


The most commonly occurring drug interactions are listed below: - Drugs that may increase plasma phenytoin concentrations include: acute alcohol intake, amiodarone, chboramphenicol, chlordiazepoxide, cimetidine, diazepam, dicumarol, disulfiram, estrogens, ethosuximide, fluoxetine, H2-antagonists, halothane, isoniazid, methylphenidate, phenothiazines, phenylbutazone, salicylates, succinimides, sulfonamides, tolbutamide, trazodone


The actions of the benzodiazepines may be potentiated by barbiturates, narcotics, phenothiazines, monoamine oxidase inhibitors or other antidepressants.


Suppression by verapamil of bombesin-enhanced peritoneal metastasis of intestinal adenocarcinomas induced by azoxymethane in wistar rats.


Vitamin A: Because of the relationship of Accutane to vitamin A, patients should be advised against taking vitamin supplements containing vitamin A to avoid additive toxic effects


The principal drugs given (number of patients in parentheses) were: cardiac glycosides (115), sedatives and hypnotics (103), coronary vasodilators (52), oral hypoglycemics (45), cough and cold preparations (45), NSAIDs (38), antihyperlipidemics (29), antigout drugs (24), oral contraceptives (18), bronchodilators (13), insulin (10), and beta blockers (10).


Potassium-sparing diuretics (spironolactone, amiloride, triamterene, and others) or potassium supplements can increase the risk of hyperkalemia.


There have been reports of theophylline-related side effects in patients on concomitant therapy with quinolones and theophylline.


Coadministration of Itraconazole with oral midazolam or triazolam has resulted in elevated plasma concentrations of the latter two drugs.


Antiretroviral regimens consisted of two reverse transcriptase inhibitors and one protease inhibitor.


Oral contraceptives: Aprepitant, when given once daily for 14 days as a 100-mg capsule with an oral contraceptive containing 35 mcg of ethinyl estradiol and 1 mg of norethindrone, decreased the AUC of ethinyl estradiol by 43%, and decreased the AUC of norethindrone by 8%;


INDOCIN can reduce the antihypertensive effects of captopril and losartan.


This effect of aspirin (which also lowers serum concentrations of other nonsteroidal anti-inflammatory drugs given with it) has been demonstrated in patients with rheumatoid arthritis (n= 15) as well as normal volunteers (n= 16).


Serious toxicity may result if dextromethorphan is coadministered with monoamine oxidase inhibitors (MAOIs).


Methotrexate: Caution should be used if diflunisal is administered concomitantly with methotrexate.


Auranofin should be avoided by patients with a history of serious reaction to any gold medication, including Solganal and Myochrysine.


The daily dose of ENABLEX should not exceed 7.5 mg when coadministered with potent CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, ritonavir, nelfinavir, clarithromycin and nefazadone) .


When taken orally , imidazole compounds like ketoconazole may enhance the anticoagulant effect of coumarin-like drugs.


Chronic administration of phenobarbital, a known enzyme inducer, may be associated with a decrease in the plasma half-life of fenoprofen.


Concomitant administration of FACTIVE and calcium carbonate, cimetidine, omeprazole, or an estrogen/progesterone oral contraceptive produced minor changes in the pharmacokinetics of gemifloxacin, which were considered to be without clinical significance.


Magnesium- and/or aluminum-containing antacids, products containing ferrous sulfate (iron), multivitamin preparations containing zinc or other metal cations, or Videx (didanosine) chewable/buffered tablets or the pediatric powder for oral solution should not be taken within 3 hours before or 2 hours after FACTIVE.


Furosemide should not be used concomitantly with ethacrynic acid because of the possibility of ototoxicity.


Diuretics: Patients on diuretics, especially those with intravascular volume depletion, may occasionally experience an excessive reduction of blood pressure after initiation of therapy with fosinopril sodium.


Hypersensitivity reactions have been reported in patients receiving combination regimens containing sequential high dose PROLEUKIN and antineoplastic agents, specifically, dacarbazine, cis-platinum, tamoxifen and interferon-alfa.


Conjugation at NaCMC with cysteine moieties significantly improves the intestinal permeation of the hydrophilic molecule NaFlu and the model peptide drugs bacitracin and insulin in vitro, therefore this conjugated system maybe useful for peroral administration of peptide drugs in the future.


To avoid this interaction, delavirdine or indinavir should be given 1 hour prior to dosing with VIDEX.


The clinical significance of this reduction is not known, hence zalcitabine is not recommended to be ingested simultaneously with magnesium/aluminum-containing antacids.


Cytadren accelerates the metabolism of dexamethasone;


Absorption of tetracyclines is impaired by antacids containing aluminum, calcium, or magnesium, and iron-containing preparations.


Etonogestrel may interact with the following medications: acetaminophen (Tylenol), antibiotics such as ampicillin and tetracycline, anticonvulsants (Dilantin, Phenobarbital, Tegretol, Trileptal, Topamax, Felbatol), antifungals (Gris-PEG, Nizoral, Sporanox), atorvastatin (Lipitor), clofibrate (Atromid-S), cyclosporine (Neoral, Sandimmune), HIV drugs classified as protease inhibitors (Agenerase, Crixivan, Fortovase, Invirase, Kaletra, Norvir, Viracept), morphine (Astramorph, Kadian, MS Contin), phenylbutazone, prednisolone (Prelone), rifadin (rifampin), St. Johns wort, temazepam, theophylline (Theo-Dur), and vitamin C.


In general, these are drugs that have one or more pharmacologic activities similar to bepridil hydrochloride, including anti-arrhythmic agents such as quinidine and procainamide, cardiac glycosides and tricyclic anti-depressants.


The administration of local anesthetic solutions containing epinephrine or norepinephrine to patients receiving monoamine oxidase inhibitors or tricyclic antidepressants may produce severe, prolonged hypertension.


Concurrent use of rifampin increases the metabolic clearance of ZEBETA, resulting in a shortened elimination half-life of ZEBETA.


Quinolones, including norfloxacin, may enhance the effects of oral anticoagulants, including warfarin or its derivatives or similar agents.


In addition, results from regression analyses of patient pharmacokinetic data suggest that co-administration of other inducers of drug clearance (efavirenz, nevirapine, phenytoin, dexamethasone, or carbamazepine) with CANCIDAS may result in clinically meaningful reductions in caspofungin concentrations.


These drugs include the thiazides and other diuretics, corticosteroids, phe-nothiazines, thyroid products, estrogens, oral contraceptives, phenytoin, nicotinic acid, sympathomimet-ics, calcium channel blocking drugs, and isoniazid.


Therefore, when hydroflumethiazide and nonsteroidal anti-inflammatory agents are used concomitantly, the patient should be observed closely to determine if the desired effect of the diuretic is obtained.)


Other Potentially Important Drug Interactions: Benzodiazepines: Benzodiazepines metabolized by hepatic oxidation (e.g., alprazolam, midazolam, triazolam elc.) should be used with caution because the clearance of these drugs is likely to be reduced by fluvoxamine.


Drugs that reportedly may increase oral anticoagulant response, ie, increased prothrombin response, in man include:alcohol*;allopurinol;aminosalicylic acid;amiodarone;anabolic steroids;antibiotics;bromelains;chloral hydrate*;chlorpropamide;chymotrypsin;cimetidine;cinchophen;clofibrate;dextran;dextrothyroxine;diazoxide;dietary deficiencies;diflunisal;disulfiram;drugs affecting blood elements;ethacrynic acid;fenoprofen;glucagon;hepatotoxic drugs;ibuprofen;indomethacin;influenza virus vaccine;inhalation anesthetics;mefenamic acid;methyldopa;methylphenidate;metronidazole;miconazole;monoamine oxidase inhibitors;nalidixic acid;naproxen;oxolinic acid;oxyphenbutazone;pentoxifylline;phenylbutazone;phenyramidol;phenytoin;prolonged hot weather;prolonged narcotics;pyrazolones;quinidine;quinine;ranitidine*;salicylates;sulfinpyrazone;sulfonamides, long acting;sulindac;thyroid drugs;tolbutamide;triclofos sodium;trimethoprim/sulfamethoxazole;unreliable prothrombin time determinations;warfarin sodium overdosage.


Cephalosporins-Cephalosporins containing side chains of N-methylthiotetrazole (cefmenoxime, cefoperazone, cefotetan, cefamandole, latamoxef) or methylthiadiazole (cefazolin) can cause vitamin K deficiency and hypoprothrombinemia.


Consequently, concomitant administration of Aprepitant with strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, nefazodone, troleandomycin, clarithromycin, ritonavir, nelfinavir) should be approached with caution.


Concomitant use of SPRYCEL and drugs that inhibit CYP3A4 (eg, ketoconazole, itraconazole, erythromycin, clarithromycin, ritonavir, atazanavir, indinavir, nefazodone, nelfinavir, saquinavir, telithromycin) may increase exposure to dasatinib and should be avoided.


Probenecid: As with other b-lactam antibiotics, co-administration of probenecid with cefditoren pivoxil resulted in an increase in the plasma exposure of cefditoren, with a 49% increase in mean Cmax, a 122% increase in mean AUC, and a 53% increase in half-life.


Anticonvulsants: In a pharmacokinetic study, maximum plasma concentrations of felodipine were considerably lower in epileptic patients on long-term anticonvulsant therapy (eg, phenytoin, carbamazepine, or phenobarbital) than in healthy volunteers.


Should it be decided to discontinue therapy in patients receiving beta-blockers and clonidine concurrently, the beta-blocker should be discontinued slowly over several days before the gradual withdrawal of clonidine.


Two of 16 subjects dosed simultaneously with Vardenafil 10 mg and tamsulosin 0.4 mg experienced a standing systolic blood pressure below 85 mm Hg.


Anticholinergic agents: Although ipratropium bromide is minimally absorbed into the systemic circulation, there is some potential for an additive interaction with concomitantly used anticholinergic medications.


Pharmacokinetic data from these patients demonstrated a decrease in paclitaxel clearance of approximately 33% when TAXOL was administered following cisplatin.


Literature reports indicate that coadministration of indomethacin may reduce the natriuretic and antihypertensive effects of furosemide in some patients by inhibiting prostaglandin synthesis.


No interactions have been observed between nizatidine and theophylline, chlordiazepoxide, lorazepam, lidocaine, phenytoin, and warfarin.


Central Nervous System Depressants: The concomitant use of DURAGESIC  (fentanyl transdermal system) with other central nervous system depressants, including but not limited to other opioids, sedatives, hypnotics, tranquilizers (e.g., benzodiazepines), general anesthetics, phenothiazines, skeletal muscle relaxants, and alcohol, may cause respiratory depression, hypotension, and profound sedation, or potentially result in coma or death.


Digitalis: Thyroid preparations may potentiate the toxic effects of digitalis.


Probenecid : Probenecid is known to interact with the metabolism or renal tubular excretion of many drugs (e.g., acetaminophen, acyclovir, angiotensin-converting enzyme inhibitors, aminosalicylic acid, barbiturates, benzodiazepines, bumetanide, clofibrate, methotrexate, famotidine, furosemide, nonsteroidal anti-inflammatory agents, theophylline, and zidovudine).


Oral Anticoagulants: In some normal volunteers, the concomitant administration of diflunisal and warfarin, acenocoumarol, or phenprocoumon resulted in prolongation of prothrombin time.


Pharmacologic studies indicate that there may be additive effects in prolonging AV conduction when using beta-blockers or digitalis concomitantly with Tiazac.


Benzthiazide may interact with alcohol, blood thinners, decongestant drugs (allergy, cold, and sinus medicines), diabetic drugs, lithium, norepinephrine, NSAIDs like Aleve or Ibuprofen, and high blood pressure medications.


Levodopa and Amantadine: Limited clinical data suggest a higher incidence of adverse experiences in patients receiving bupropion concurrently with either levodopa or amantadine.


Oral neomycin sulfate may enhance the effect of coumarin in anticoagulants by decreasing vitamin K availability.


There is one report suggesting that the concomitant use of trazodone hydrochloride (Desyrel) and buspirone HCl may have caused 3- to 6-fold elevations on SGPT (ALT) in a few patients.


Because Nalfon has not been shown to produce any additional effect beyond that obtained with aspirin alone and because aspirin increases the rate of excretion of Nalfon, the concomitant use of Nalfon and salicylates is not recommended.


Itraconazole decreases busulfan clearance by up to 25%, and may produce AUCs   1500  M min in some patients.


Thyroid Physiology: The following agents may alter thyroid hormone or TSH levels, generally by effects on thyroid hormone synthesis, secretion, distribution, metabolism, hormone action, or elimination, or altered TSH secretion: aminoglutethimide, p-aminosalicylic acid, amiodarone, androgens and related anabolic hormones, complex anions (thiocyanate, perchlorate, pertechnetate), antithyroid drugs, b-adrenergic blocking agents, carbamazepine, chloral hydrate, diazepam, dopamine and dopamine agonists, ethionamide, glucocorticoids, heparin, hepatic enzyme inducers, insulin, iodinated cholestographic agents, iodine-containing compounds, levodopa, lovastatin, lithium, 6-mercaptopurine, metoclopramide, mitotane, nitroprusside, phenobarbital, phenytoin, resorcinol, rifampin, somatostatin analogs, sulfonamides, sulfonylureas, thiazide diuretics.


Phenobarbital: Coadministration of felbamate with phenobarbital causes an increase in phenobarbital plasma concentrations, In 12 otherwise healthy male volunteers ingesting phenobarbital, the steady-state trough (Cmin) phenobarbital concentration was 14.2 micrograms/mL.


Nephrotoxic agents : Concomitant administration of VISTIDE and agents with nephrotoxic potential [e.g., intravenous aminoglycosides (e.g., tobramycin, gentamicin, and amikacin), amphotericin B, foscarnet, intravenous pentamidine, vancomycin, and non-steroidal anti-inflammatory agents] is contraindicated.


Data from in vitro studies of benzodiazepines other than alprazolam suggest a possible drug interaction for the following: ergotamine, cyclosporine, amiodarone, nicardipine, and nifedipine.


Drugs and other substances demonstrated to be CYP 3A inhibitors on the basis of clinical studies involving benzodiazepines metabolized similarly to alprazolam or on the basis of in vitro studies with alprazolam or other benzodiazepines (caution is recommended during coadministration with alprazolam): Available data from clinical studies of benzodiazepines other than alprazolam suggest a possible drug interaction with alprazolam for the following: diltiazem, isoniazid, macrolide antibiotics such as erythromycin and clarithromycin, and grapefruit juice.


Interaction of ketamine and halothane in rats.


Ketoconazole (200 mg once daily) produced a 10-fold increase in vardenafil AUC and a 4-fold increase in Cmax when co-administered with Vardenafil (5 mg) in healthy volunteers.


Drug/Laboratory Test Interactions The following drugs or moieties are known to interfere with laboratory tests performed in patients on thyroid hormone therapy: androgens, corticosteroids, estrogens, oral contraceptives containing estrogens, iodine-containing preparations and the numerous preparations containing salicylates.


Therefore, co-administration of Duloxetine with other drugs that are extensively metabolized by this isozyme and which have a narrow therapeutic index, including certain antidepressants (tricyclic antidepressants [TCAs], such as nortriptyline, amitriptyline, and imipramine), phenothiazines and Type 1C antiarrhythmics (e.g., propafenone, flecainide), should be approached with caution.


The concurrent use of two or more drugs with anticholinergic activity--such as an antipsychotic drug (eg, chlorpromazine), an antiparkinsonian drug (eg, trihexyphenidyl), and/or a tricyclic antidepressant (eg, amitriptyline)--commonly results in excessive anticholinergic effects, including dry mouth and associated dental complications, blurred vision, and, in patients exposed to high temperature and humidity, hyperpyrexia.


Rifampin markedly increases the metabolic clearance of amprenavir, and coadministration is contraindicated.


Loop Diuretics: Furosemide administered concurrently with captopril does not alter the pharmacokinetics of captopril in renally impaired hypertensive patients.


Diphenhydramine hydrochloride has additive effects with alcohol and other CNS depressants (hypnotics, sedatives, tranquilizers, etc).


If isradipine therapy is initiated in a patient currently receiving cimetidine careful monitoring for adverse reactions is advised and downward dose adjustment may be required.


Diuretic agents reduce the renal clearance of lithium and add a high risk of lithium toxicity.


Etonogestrel may interact with the following medications: acetaminophen (Tylenol), antibiotics such as ampicillin and tetracycline, anticonvulsants (Dilantin, Phenobarbital, Tegretol, Trileptal, Topamax, Felbatol), antifungals (Gris-PEG, Nizoral, Sporanox), atorvastatin (Lipitor), clofibrate (Atromid-S), cyclosporine (Neoral, Sandimmune), HIV drugs classified as protease inhibitors (Agenerase, Crixivan, Fortovase, Invirase, Kaletra, Norvir, Viracept), morphine (Astramorph, Kadian, MS Contin), phenylbutazone, prednisolone (Prelone), rifadin (rifampin), St. Johns wort, temazepam, theophylline (Theo-Dur), and vitamin C.


Veratrum alkaloids: Amphetamines inhibit the hypotensive effect of veratrum alkaloids.


The drug interaction between warfarin and rifampin is not well known.


At least 3 weeks should elapse between discontinuation of dexfenfluramine and initiation of treatment with a MAO inhibitor.


This article looks at five commonly used immunosuppressive drugs in turn (corticosteroids, cyclosporin, azathioprine, methotrexate, cyclophosphamide), discussing the main, non-infection, unwanted effects, ways to avoid them and what to do if problems arise.


Ganciclovir: Administration of VIDEX 2 hours prior to or concurrent with oral ganciclovir was associated with a 111 (114)% increase in the steady-state AUC of didanosine (n = 12).


Although specific drug interaction studies have not been conducted with ALPHAGAN P, the possibility of an additive or potentiating effect with CNS depressants (alcohol, barbiturates, opiates, sedatives, or anesthetics) should be considered.


In patients receiving nonselective monoamine oxidase inhibitors (MAOIs) (e.g., selegiline hydrochloride) in combination with serotoninergic agents (e.g., fluoxetine, fluvoxamine, paroxetine, sertraline, venlafaxine), there have been reports of serious, sometimes fatal, reactions.


Antidepressants, tricyclic Amphetamines may enhance the activity of tricyclic antidepressants or sympathomimetic agents;


Concurrent use of butorphanol with central nervous system depressants (e.g., alcohol, barbiturates, tranquilizers, and antihistamines) may result in increased central nervous system depressant effects.


Narcotic analgesics may potentiate the hypotensive effects of clonidine.


The use of antacids should be considered in place of H2 blockers or proton pump inhibitors in patients receiving SPRYCEL therapy.


Leucovorin: The concentration of 5-fluorouracil is increased and its toxicity may be enhanced by leucovorin.


Drugs that reportedly may increase oral anticoagulant response, ie, increased prothrombin response, in man include:alcohol*;allopurinol;aminosalicylic acid;amiodarone;anabolic steroids;antibiotics;bromelains;chloral hydrate*;chlorpropamide;chymotrypsin;cimetidine;cinchophen;clofibrate;dextran;dextrothyroxine;diazoxide;dietary deficiencies;diflunisal;disulfiram;drugs affecting blood elements;ethacrynic acid;fenoprofen;glucagon;hepatotoxic drugs;ibuprofen;indomethacin;influenza virus vaccine;inhalation anesthetics;mefenamic acid;methyldopa;methylphenidate;metronidazole;miconazole;monoamine oxidase inhibitors;nalidixic acid;naproxen;oxolinic acid;oxyphenbutazone;pentoxifylline;phenylbutazone;phenyramidol;phenytoin;prolonged hot weather;prolonged narcotics;pyrazolones;quinidine;quinine;ranitidine*;salicylates;sulfinpyrazone;sulfonamides, long acting;sulindac;thyroid drugs;tolbutamide;triclofos sodium;trimethoprim/sulfamethoxazole;unreliable prothrombin time determinations;warfarin sodium overdosage.


Because fluvoxamine reduces the clearance of both diazepam and its active metabolite, N-desmethyldiazepam, there is a strong likelihood of substantial accumulation of both species during chronic co-administration.


Levothyroxine Sodium Absorption: The following agents may bind and decrease absorption of levothyroxine sodium from the gastrointestinal tract: aluminum hydoxide, cholestyramine resin, colestipol hydrochloride, ferrous sulfate, sodium polystyrene sulfonate, soybean flour (e.g., infant formula), sucralfate.


Agents that are CYP3A4 inhibitors that have been found, or are expected, to increase plasma levels of EQUETROTM are the following: Acetazolamide, azole antifungals, cimetidine, clarithromycin(1), dalfopristin, danazol, delavirdine, diltiazem, erythromycin(1), fluoxetine, fluvoxamine, grapefruit juice, isoniazid, itraconazole, ketoconazole, loratadine, nefazodone, niacinamide, nicotinamide, protease inhibitors, propoxyphene, quinine, quinupristin, troleandomycin, valproate(1), verapamil, zileuton.


Barbiturates, phenytoin, or rifampin increased metabolic clearance of fludrocortisone acetate because of the induction of hepatic enzymes.


While all the selective serotonin reuptake inhibitors (SSRIs), e.g., fluoxetine, sertraline, paroxetine, and fluvoxamine, inhibit P450 2D6, they may vary in the extent of inhibition.


- Drugs whose efficacy is impaired by phenytoin include: anticoagulants, corticosteroids, coumarin, digitoxin, doxycycline, estrogens, furosemide, oral contraceptives, rifampin, quinidine, theophylline, vitamin D.


This appears to be the only clinically relevant interaction of this kind with Mefloquine, although theoretically, coadministration of other drugs known to alter cardiac conduction (eg, anti-arrhythmic or beta-adrenergic blocking agents, calcium channel blockers, antihistamines or H1-blocking agents, tricyclic antidepressants and phenothiazines) might also contribute to a prolongation of the QTc interval.


Before taking glimepiride, tell your doctor if you are taking any of the following medicines: - aspirin or another salicylate such as magnesium/choline salicylate (Trilisate), salsalate (Disalcid, others), choline salicylate (Arthropan), magnesium salicylate (Magan), or bismuth subsalicylate (Pepto-Bismol);


An intravenous injection of perchlorate given later also produces a complete and immediately beginning depletion of pertechnetate already accumulated in the thyroid, within a period of 195 min after 99m-TcO-4-injection with a corresponding increase in blood levels.


Antacids containing magnesium, aluminum, or calcium;


Therefore, patients on propranolol should be observed when COLESTID Tablets are either added or deleted from a therapeutic regimen.


Barbiturates may decrease the effectiveness of oral contraceptives, certain antibiotics, quinidine, theophylline, corticosteroids, anticoagulants, and beta blockers.


Antacids, kaolin-pectin, sulfasalazine, neomycin, cholestyramine, certain anticancer drugs, and metoclopramide may interfere with intestinal digoxin absorption, resulting in unexpectedly low serum concentrations.


In addition, most macrolides are contraindicated in patients receiving terfenadine therapy who have pre-existing cardiac abnormalities (arrhythmia, bradycardia, QT c interval prolongation, ischemic heart disease, congestive heart failure, etc.) or electrolyte disturbances.


Drugs That Induce CYP3A4 (Rifampicin) Racemic zopiclone exposure was decreased 80% by concomitant useof rifampicin, a potent inducer of CYP3A4.


Heparin Sodium Injection should not be mixed with doxorubicin, droperidol, ciprofloxacin, or mitoxantrone, since it has been reported that these drugs are incompatible with heparin and a precipitate may form.


Binding to Serum Proteins: The following agents may either inhibit levothyroxine sodium binding to serum proteins or alter the concentrations of serum binding proteins: androgens and related anabolic hormones, asparaginase, clofibrate, estrogens and estrogen-containing compounds, 5-fluorouracil, furosemide, glucocorticoids, meclofenamic acid, mefenamic acid, methadone, perphenazine, phenylbutazone, phenytoin, salicylates, tamoxifen.


Synergism between xanthine bronchodilators (e.g., theophylline), ephedrine, and other sympathomimetic bronchodilators has been reported.


Antifungals: In vitro and/or in vivo data indicate that fluconazole, itraconazole, and oral ketoconazole markedly inhibit the metabolism of cisapride, which can result in an increase in plasma cisapride levels and prolongation of the QT interval on the ECG.


The concomitant administration of quinolones including norfloxacin with glyburide (a sulfonylurea agent) has, on rare occasions, resulted in severe hypoglycemia.


Lamivudine: In vitro studies in peripheral blood mononuclear cells, U937 and Molt-4 cells revealed that lamivudine significantly inhibited zalcitabine phosphorylation in a dose dependent manner.


Agents that are CYP3A4 inhibitors that have been found, or are expected, to increase plasma levels of EQUETROTM are the following: Acetazolamide, azole antifungals, cimetidine, clarithromycin(1), dalfopristin, danazol, delavirdine, diltiazem, erythromycin(1), fluoxetine, fluvoxamine, grapefruit juice, isoniazid, itraconazole, ketoconazole, loratadine, nefazodone, niacinamide, nicotinamide, protease inhibitors, propoxyphene, quinine, quinupristin, troleandomycin, valproate(1), verapamil, zileuton.


Agents that have been found, or are expected to have decreased plasma levels in the presence of EQUETROTM due to induction of CYP enzymes are the following: Acetaminophen, alprazolam, amitriptyline, bupropion, buspirone, citalopram, clobazam, clonazepam, clozapine, cyclosporin, delavirdine, desipramine, diazepam, dicumarol, doxycycline, ethosuximide, felbamate, felodipine, glucocorticoids, haloperidol, itraconazole, lamotrigine, levothyroxine, lorazepam, methadone, midazolam, mirtazapine, nortriptyline, olanzapine, oral contraceptives(3), oxcarbazepine, Phenytoin(4), praziquantel, protease inhibitors, quetiapine, risperidone, theophylline, topiramate, tiagabine, tramadol, triazolam, valproate, warfarin(5) , ziprasidone, and zonisamide.


Probenecid: As with other b-lactam antibiotics, probenecid inhibits the renal excretion of cefdinir, resulting in an approximate doubling in A.C. a 54% increase in peak cefdinir plasma levels, and a 50% prolongation in the apparent elimination half-life.


SUSTIVA has the potential to decrease plasma concentrations of itraconazole and ketoconazole.


Ethopropazine can interact with chlorpromazine, increasing the metabolism of chlorpromazine.


Protease inhibitors: Amprenavir, lopinavir, nelfinavir, and ritonavir have been shown to decrease plasma levels of combination hormonal contraceptives;


Co-treatment with the potent CYP3A4 inhibitor ketoconazole increases erlotinib AUC by 2/3.


There have been reports of interactions of erythromycin with carbamazepine, cyclosporine, tacrolimus, hexobarbital, phenytoin, alfentanil, cisapride, disopyramide, lovastatin, bromocriptine, valproate, terfenadine, and astemizole.


(Thiazide drugs may increase the responsiveness to tubocurarine.)


Lithium: Ibuprofen produced an elevation of plasma lithium levels and a reduction in renal lithium clearance in a study of eleven normal volunteers.


If CEFOTAN and an aminoglycoside are used concomitantly, renal function should be carefully monitored, because nephrotoxicity may be potentiated.


ZEBETA should be used with care when myocardial depressants or inhibitors of AV conduction, such as certain calcium antagonists (particularly of the phenylalkylamine [verapamil] and benzothiazepine [diltiazem] classes), or antiarrhythmic agents, such as disopyramide, are used concurrently.


DIGOXIN: Plasma digoxin levels and digoxin clearance at steady-state were not affected by co-administration of 0.2 mg cerivastatin sodium.


Two different types of therapy with magnesium are used: physiological oral magnesium supplementation which is totally atoxic since it palliates magnesium deficiencies by simply normalizing the magnesium intake and pharmacological magnesium therapy which may induce toxicity since it creates iatrogenic magnesium overload.


Lotensin has been used concomitantly with beta-adrenergic-blocking agents, calcium-channel-blocking agents, diuretics, digoxin, and hydralazine, without evidence of clinically important adverse interactions.


Concomitant single dose administration of valdecoxib 20 mg with multiple doses of ketoconazole and fluconazole produced a significant increase in exposure of valdecoxib.


Aspirin: CELEBREX can be used with low dose aspirin.


Other drugs which may enhance the neuromuscular blocking action of nondepolarizing agents such as NIMBEX include certain antibiotics (e. g., aminoglycosides, tetracyclines, bacitracin, polymyxins, lincomycin, clindamycin, colistin, and sodium colistemethate), magnesium salts, lithium, local anesthetics, procainamide, and quinidine.


Drugs that have been associated with peripheral neuropathy include antiretroviral nucleoside analogues, chloramphenicol, cisplatin, dapsone, disulfiram, ethionamide, glutethimide, gold, hydralazine, iodoquinol, isoniazid, metronidazole, nitrofurantoin, phenytoin, ribavirin, and vincristine.


Drugs that reportedly may increase oral anticoagulant response, ie, increased prothrombin response, in man include:alcohol*;allopurinol;aminosalicylic acid;amiodarone;anabolic steroids;antibiotics;bromelains;chloral hydrate*;chlorpropamide;chymotrypsin;cimetidine;cinchophen;clofibrate;dextran;dextrothyroxine;diazoxide;dietary deficiencies;diflunisal;disulfiram;drugs affecting blood elements;ethacrynic acid;fenoprofen;glucagon;hepatotoxic drugs;ibuprofen;indomethacin;influenza virus vaccine;inhalation anesthetics;mefenamic acid;methyldopa;methylphenidate;metronidazole;miconazole;monoamine oxidase inhibitors;nalidixic acid;naproxen;oxolinic acid;oxyphenbutazone;pentoxifylline;phenylbutazone;phenyramidol;phenytoin;prolonged hot weather;prolonged narcotics;pyrazolones;quinidine;quinine;ranitidine*;salicylates;sulfinpyrazone;sulfonamides, long acting;sulindac;thyroid drugs;tolbutamide;triclofos sodium;trimethoprim/sulfamethoxazole;unreliable prothrombin time determinations;warfarin sodium overdosage.


Patients in a clinical study who were on established therapy with sulfasalazine, to which ENBREL was added, were noted to develop a mild decrease in mean neutrophil counts in comparison to groups treated with either ENBREL CI or sulfasalazine alone.


Lithium generally should not be given with diuretics because they reduce lithiums renal clearance and add a high risk of lithium toxicity.


Thus, when ibuprofen and lithium are administered concurrently, subjects should be observed carefully for signs of lithium toxicity.


Agents that have been found, or are expected to have decreased plasma levels in the presence of EQUETROTM due to induction of CYP enzymes are the following: Acetaminophen, alprazolam, amitriptyline, bupropion, buspirone, citalopram, clobazam, clonazepam, clozapine, cyclosporin, delavirdine, desipramine, diazepam, dicumarol, doxycycline, ethosuximide, felbamate, felodipine, glucocorticoids, haloperidol, itraconazole, lamotrigine, levothyroxine, lorazepam, methadone, midazolam, mirtazapine, nortriptyline, olanzapine, oral contraceptives(3), oxcarbazepine, Phenytoin(4), praziquantel, protease inhibitors, quetiapine, risperidone, theophylline, topiramate, tiagabine, tramadol, triazolam, valproate, warfarin(5) , ziprasidone, and zonisamide.


Drugs that have been reported to diminish oral anticoagulant response, ie, decreased prothrom-bin time response, in man significantly include: adrenocortical steroids;alcohol*;antacids;antihistamines;barbiturates;carbamazepine;chloral hydrate*;chlordiazepoxide;cholestyramine;diet high in vitamin K;diuretics*;ethchlorvynol;glutethimide;griseofulvin;haloperidol;meprobamate;oral contraceptives;paraldehyde;primidone;ranitidine*;rifampin;unreliable prothrombin time determinations;vitamin C;warfarin sodium under-dosage.


It is recommended that plasma lithium levels be monitored when ketoprofen is coadministered with lithium.


Probenecid or Cimetidine: Concomitant administration of probenecid or cimetidine decreases the elimination of zalcitabine, most likely by inhibition of renal tubular secretion of zalcitabine.


Ephedrine: Ephedrine may enhance the metabolic clearance of corticosteroids, resulting in decreased blood levels and lessened physiologic activity, thus requiring an increase in corticosteroid dosage.


Probenecid : Probenecid is known to interact with the metabolism or renal tubular excretion of many drugs (e.g., acetaminophen, acyclovir, angiotensin-converting enzyme inhibitors, aminosalicylic acid, barbiturates, benzodiazepines, bumetanide, clofibrate, methotrexate, famotidine, furosemide, nonsteroidal anti-inflammatory agents, theophylline, and zidovudine).


However, interactions may be expected, and UROXATRAL should NOT be used in combination with other alpha-blockers.


Sympathomimetic amines may reduce the antihypertensive effects of reserpine, veratrum alkaloids, methyldopa and mecamylamine.


Co-administration of nelfinavir at steady-state with a single dose of azithromycin (2 x 600 mg tablets) results in increased azithromycin serum concentrations.


The intake of furosemide and sucralfate should be separated by at least two hours.


Cimetidine has been shown to increase the bioavailability of labetalol HCl.


However, since aspirin, NSAIDs, and bisphosphonates are all associated with gastrointestinal irritation, caution should be exercised in the concomitant use of aspirin or NSAIDs with Ibandronate.


FLUOTHANE may augment the hypotension caused by the ganglionic-blocking effect of tubocurarine.


Therefore, ketoconazole should be administered with caution with intranasal ciclesonide.


Interactions with Other Antiretroviral Drugs: Significant decreases in the AUC of delavirdine (20%) and indinavir (84%) occurred following simultaneous administration of these agents with VIDEX.


Therefore, co-administration of Duloxetine with other drugs that are extensively metabolized by this isozyme and which have a narrow therapeutic index, including certain antidepressants (tricyclic antidepressants [TCAs], such as nortriptyline, amitriptyline, and imipramine), phenothiazines and Type 1C antiarrhythmics (e.g., propafenone, flecainide), should be approached with caution.


Central Nervous System Depressants: The concomitant use of DURAGESIC  (fentanyl transdermal system) with other central nervous system depressants, including but not limited to other opioids, sedatives, hypnotics, tranquilizers (e.g., benzodiazepines), general anesthetics, phenothiazines, skeletal muscle relaxants, and alcohol, may cause respiratory depression, hypotension, and profound sedation, or potentially result in coma or death.


Systemic exposure to acetaminophen is expected to be increased when coadministered with Gleevec.


Drug Interactions: Flupenthixol may interact with some drugs, like Monoamine oxidase inhibitors (MAOI): MAOI could theoretically affect flupenthixol pharmacodynamics - Arecoline - Eproxindine - Ethanol: Flupenthixol and Ethanol cause additive CNS depression - Tricyclic antidepressants: Flupenthixol increases the effect of Tricyclic antidepressants


Additive adverse effects resulting from cholinergic blockade may occur when LEVSIN is administered concomitantly with other antimuscarinics, amantadine, haloperidol, phenothiazines, monoamine oxidase (MAO) inhibitors, tricyclic antidepressants or some antihistamines.


Intravenous Adenocard (adenosine) has been effectively administered in the presence of other cardioactive drugs, such as quinidine, beta-adrenergic blocking agents, calcium channel blocking agents, and angiotensin converting enzyme inhibitors, without any change in the adverse reaction profile.


Anakinra: Concurrent administration of anakinra (an interleukin-1 antagonist) and another TNF-blocking agent has been associated with an increased risk of serious infections, an increased risk of neutropenia and no additional benefit compared to these medicinal products alone.


Previous studies have demonstrated a significant reduction in the oral bioavailability of trovafloxacin and ciprofloxacin when administered concomitantly with an intravenous opiate such as morphine.


If concomitant treatment with sumatriptan and an SSRI (e.g., fluoxetine, fluvoxamine, paroxetine, sertraline, citalopram, escitalopram) is clinically warranted, appropriate observation of the patient is advised.


Agents that have been found, or are expected to have decreased plasma levels in the presence of EQUETROTM due to induction of CYP enzymes are the following: Acetaminophen, alprazolam, amitriptyline, bupropion, buspirone, citalopram, clobazam, clonazepam, clozapine, cyclosporin, delavirdine, desipramine, diazepam, dicumarol, doxycycline, ethosuximide, felbamate, felodipine, glucocorticoids, haloperidol, itraconazole, lamotrigine, levothyroxine, lorazepam, methadone, midazolam, mirtazapine, nortriptyline, olanzapine, oral contraceptives(3), oxcarbazepine, Phenytoin(4), praziquantel, protease inhibitors, quetiapine, risperidone, theophylline, topiramate, tiagabine, tramadol, triazolam, valproate, warfarin(5) , ziprasidone, and zonisamide.


Enoxacin interferes with the metabolism of theophylline resulting in a 42% to 74% dose-related decrease in theophylline clearance and a subsequent 260% to 350% increase in serum theophylline levels.


Coadministration of valdecoxib with doses higher than 40 mg QD omeprazole has not been studied.


Thyroid Physiology: The following agents may alter thyroid hormone or TSH levels, generally by effects on thyroid hormone synthesis, secretion, distribution, metabolism, hormone action, or elimination, or altered TSH secretion: aminoglutethimide, p-aminosalicylic acid, amiodarone, androgens and related anabolic hormones, complex anions (thiocyanate, perchlorate, pertechnetate), antithyroid drugs, b-adrenergic blocking agents, carbamazepine, chloral hydrate, diazepam, dopamine and dopamine agonists, ethionamide, glucocorticoids, heparin, hepatic enzyme inducers, insulin, iodinated cholestographic agents, iodine-containing compounds, levodopa, lovastatin, lithium, 6-mercaptopurine, metoclopramide, mitotane, nitroprusside, phenobarbital, phenytoin, resorcinol, rifampin, somatostatin analogs, sulfonamides, sulfonylureas, thiazide diuretics.


In addition, several AED s that are cytochrome P450 inducers can decrease plasma concentrations of oxcarbazepine and MHD.


Co-administration of lovastatin, atenolol, warfarin, furosemide, digoxin, celecoxib, hydrochlorothiazide, ramipril, valsartan, metformin and amlodipine did not result in clinically significant increases in aliskiren exposure.


Therefore, co-administration of tricyclic antidepressants with other drugs that are metabolized by this isoenzyme, including other antidepressants, phenothiazines, carbamazepine, and Type 1C antiarrhythmics (eg, propafenone, flecainide, and encainide), or that inhibit this enzyme (eg, quinidine), should be approached with caution.


Phenytoin, nicotine, and rifampin may decrease Clozapine plasma levels, resulting in a decrease in effectiveness of a previously effective Clozapine dose.


Because the potential interaction of efavirenz with oral contraceptives has not been fully characterized, a reliable method of barrier contraception should be used in addition to oral contraceptives.


Immediate and Extended Release Tablets The hypoglycemic action of sulfonylureas may be potentiated by certain drugs including nonsteroidal anti-inflammatory agents, some azoles and other drugs that are highly protein bound, salicylates, sulfonamides, chloramphenicol, probenecid, coumarins, monoamine oxidase inhibitors, and beta adrenergic blocking agents.


Therefore, co-administration of bupropion with drugs that are metabolized by CYP2D6 isoenzyme including certain antidepressants (e.g., nortriptyline, imipramine, desipramine, paroxetine, fluoxetine, sertraline), antipsychotics (e.g., haloperidol, risperidone, thioridazine), beta-blockers (e.g., metoprolol), and Type 1C antiarrhythmics (e.g., propafenone, flecainide), should be approached with caution and should be initiated at the lower end of the dose range of the concomitant medication.


The most commonly occurring drug interactions are listed below: - Drugs that may increase plasma phenytoin concentrations include: acute alcohol intake, amiodarone, chboramphenicol, chlordiazepoxide, cimetidine, diazepam, dicumarol, disulfiram, estrogens, ethosuximide, fluoxetine, H2-antagonists, halothane, isoniazid, methylphenidate, phenothiazines, phenylbutazone, salicylates, succinimides, sulfonamides, tolbutamide, trazodone


Phenytoin: In a single (400 mg) and multiple dose (400 mg TID) study of Neurontin in epileptic patients (N=8) maintained on phenytoin monotherapy for at least 2 months, gabapentin had no effect on the steady-state trough plasma concentrations of phenytoin and phenytoin had no effect on gabapentin pharmacokinetics.


Oral Contraceptives: Multiple dose administration of tiagabine (8 mg/day monotherapy) did not alter the pharmacokinetics of oral contraceptives in healthy women of childbearing age.


Drugs Which Require a Dose Reduction When Coadminstered With VIRACEPT Antimycobacterial agents: rifabutin


When combined with ofloxacin, KRM-1648 exhibited strong synergistic activity while only additive effects were observed with the combination of rifampicin (or rifabutin) and ofloxacin.


- a nonsteroidal anti-inflammatory drug (NSAID) such as ibuprofen (Motrin, Advil, Nuprin, others), ketoprofen (Orudis, Orudis KT, Oruvail), diclofenac (Voltaren, Cataflam), etodolac (Lodine), indomethacin (Indocin), nabumetone (Relafen), oxaprozin (Daypro), and naproxen (Anaprox, Naprosyn, Aleve);


Anticoagulants including coumarin derivatives, indandione derivatives, and platelet aggregation inhibitors such as nonsteroidal anti-inflammatory drugs (NSAIDs), and aspirin may increase the risk of bleeding when administered concomitantly with ardeparin.


Other drugs which may enhance the neuromuscular blocking action of nondepolarizing agents such as NUROMAX include certain antibiotics (e. g., aminoglycosides, tetracyclines, bacitracin, polymyxins, lincomycin, clindamycin, colistin, and sodium colistimethate), magnesium salts, lithium, local anesthetics, procainamide, and quinidine.


Agents that are CYP3A4 inhibitors that have been found, or are expected, to increase plasma levels of EQUETROTM are the following: Acetazolamide, azole antifungals, cimetidine, clarithromycin(1), dalfopristin, danazol, delavirdine, diltiazem, erythromycin(1), fluoxetine, fluvoxamine, grapefruit juice, isoniazid, itraconazole, ketoconazole, loratadine, nefazodone, niacinamide, nicotinamide, protease inhibitors, propoxyphene, quinine, quinupristin, troleandomycin, valproate(1), verapamil, zileuton.


Antihistamines may enhance the effects of tricyclic antidepressants, barbiturates, alcohol, and other CNS depressants.


- Phenothiazines (acetophenazine [e.g., Tindal], chlorpromazine [e.g., Thorazine], fluphenazine [e.g., Prolixin], mesoridazine [e.g., Serentil], perphenazine [e.g., Trilafon], prochlorperazine [e.g., Compazine], promazine [e.g., Sparine], promethazine [e.g., Phenergan], thioridazine [e.g., Mellaril], trifluoperazine [e.g., Stelazine], triflupromazine [e.g., Vesprin], trimeprazine [e.g., Temaril]) or


Beta-adrenergic receptor antagonists (beta-blockers) and BROVANA may interfere with the effect of each other when administered concurrently.


Ketoconazole: Coadministration of ketoconazole with VIRACEPT resulted in a 35% increase in nelfinavir plasma A.C.


An increase in serum lithium concentration has been reported during concomitant administration of lithium with ATACAND, so careful monitoring of serum lithium levels is recommended during concomitant use.


In patients taking an anticonvulsant (eg, valproic acid, carbamazepine, phenobarbital or phenytoin), the concomitant use of Mefloquine may reduce seizure control by lowering the plasma levels of the anticonvulsant.


Warfarin: The effects of warfarin and NSAIDs on GI bleeding are synergistic, such that users of both drugs together have a risk of serious GI bleeding higher than users of either drug alone.


Also, concomitant administration of quinolones with products containing iron, multivitamins containing zinc, or Videx (didanosine) chewable/buffered tablets or the pediatric powder for oral solution may result in low urine levels.


Levothyroxine Sodium Absorption: The following agents may bind and decrease absorption of levothyroxine sodium from the gastrointestinal tract: aluminum hydoxide, cholestyramine resin, colestipol hydrochloride, ferrous sulfate, sodium polystyrene sulfonate, soybean flour (e.g., infant formula), sucralfate.


Monoamine Oxidase Inhibitors: Coadministration of moclobemide resulted in a 27% decrease in almotriptan clearance and an increase in Cmax of approximately 6%.


Etonogestrel may interact with the following medications: acetaminophen (Tylenol), antibiotics such as ampicillin and tetracycline, anticonvulsants (Dilantin, Phenobarbital, Tegretol, Trileptal, Topamax, Felbatol), antifungals (Gris-PEG, Nizoral, Sporanox), atorvastatin (Lipitor), clofibrate (Atromid-S), cyclosporine (Neoral, Sandimmune), HIV drugs classified as protease inhibitors (Agenerase, Crixivan, Fortovase, Invirase, Kaletra, Norvir, Viracept), morphine (Astramorph, Kadian, MS Contin), phenylbutazone, prednisolone (Prelone), rifadin (rifampin), St. Johns wort, temazepam, theophylline (Theo-Dur), and vitamin C.


d-amphetamine with desipramine or protriptyline and possibly other tricyclics cause striking and sustained increases in the concentration of d-amphetamine in the brain;


Antacids: Concomitant administration of magnesium hydroxide and aluminum hydroxide does not interfere with the rate or extent of the absorption of ketoprofen administered as Orudis.


Pharmacodynamic Interactions: The CNS-depressant action of the benzodiazepine class of drugs may be potentiated by alcohol, narcotics, barbiturates, nonbarbiturate hypnotics, antianxiety agents, the phenothiazines, thioxanthene and butyrophenone classes of antipsychotic agents, monoamine oxidase inhibitors and the tricyclic antidepressants, and by other anticonvulsant drugs.


Although specific studies have not been performed, coadministration with drugs that are mainly metabolized by CYP3A4 (eg, calcium channel blockers, dapsone, disopyramide, quinine, amiodarone, quinidine, warfarin, tacrolimus, cyclosporine, ergot derivatives, pimozide, carbamazepine, fentanyl, alfentanyl, alprazolam, and triazolam) may have elevated plasma concentrations when coadministered with saquinavir;


As with some other nondepolarizing neuromuscular blocking agents, the time of onset of neuromuscular block induced by NUROMAX is lengthened and the duration of block is shortened in patients receiving phenytoin or carbamazepine.


Coadministration with compounds that are potent inducers of CYP3A4 (eg, phenobarbital, phenytoin, dexamethasone, carbamazepine) may result in decreased plasma levels of saquinavir.


Caffeine Theobromine Grepafloxacin, like other quinolones, may inhibit the metabolism of caffeine and theobromine.


The following are examples of drugs known to inhibit the metabolism of other related benzodiazepines, presumably through inhibition of CYP3A: nefazodone, fluvoxamine, cimetidine, diltiazem, isoniazide, and some macrolide antibiotics.


There have been isolated reports of patients experiencing increases in their prothrombin times when etidronate was added to warfarin therapy.


The IV methylprednisolone dose should be reduced by approximately 25%, and the oral methylprednisolone dose should be reduced by approximately 50% when coadministered with Aprepitant to achieve exposures of methylprednisolone similar to those obtained when it is given without Aprepitant.


The effect may be mediated by cimetidines known inhibition of hepatic cytochrome P-450, the enzyme system responsible for the first-pass metabolism of diltiazem.


Repeated doses of colestipol hydrochloride given prior to a single dose of propranolol in human trials have been reported to decrease propranolol absorption.


Amiodarone, disopyramide, lidocaine


The concomitant administration of griseofulvin has been reported to reduce the efficacy of oral contraceptives and to increase the incidence of breakthrough bleeding.


In a patient with a nonfunctioning thyroid gland who is receiving thyroid replacement therapy, free levothyroxine may be decreased when estrogens are started thus increasing thyroid requirements.


Warfarin: Eszopiclone 3 mg administered daily for 5 days did not affect the pharmacokinetics of (R)- or (S)-warfarin, nor were there any changes in the pharmacodynamic profile (prothrombin time) following a single 25 mg oral dose of warfarin


If a patient requires TIKOSYN and anti-ulcer therapy, it is suggested that omeprazole, ranitidine, or antacids (aluminum and magnesium hydroxides) be used as alternatives to cimetidine, as these agents have no effect on the pharmacokinetic profile of TIKOSYN.


Although additional drug interaction studies have not been conducted, the most common medications used concomitantly with anagrelide in clinical trials were aspirin, acetaminophen, furosemide, iron, ranitidine, hydroxyurea, and allopurinol.


Concomitant use of L-phenylalanine and non-selective MAO inhibitors may cause hypertension.


Oral contraceptives: Aprepitant, when given once daily for 14 days as a 100-mg capsule with an oral contraceptive containing 35 mcg of ethinyl estradiol and 1 mg of norethindrone, decreased the AUC of ethinyl estradiol by 43%, and decreased the AUC of norethindrone by 8%;


Thyroid Physiology: The following agents may alter thyroid hormone or TSH levels, generally by effects on thyroid hormone synthesis, secretion, distribution, metabolism, hormone action, or elimination, or altered TSH secretion: aminoglutethimide, p-aminosalicylic acid, amiodarone, androgens and related anabolic hormones, complex anions (thiocyanate, perchlorate, pertechnetate), antithyroid drugs, b-adrenergic blocking agents, carbamazepine, chloral hydrate, diazepam, dopamine and dopamine agonists, ethionamide, glucocorticoids, heparin, hepatic enzyme inducers, insulin, iodinated cholestographic agents, iodine-containing compounds, levodopa, lovastatin, lithium, 6-mercaptopurine, metoclopramide, mitotane, nitroprusside, phenobarbital, phenytoin, resorcinol, rifampin, somatostatin analogs, sulfonamides, sulfonylureas, thiazide diuretics.


Aripiprazole dose should be reduced to one-half of its normal dose when concomitant administration of quinidine with aripiprazole occurs.


- The action of sulphonylureas and insulin may be enhanced by Bezalip or Bezalip retard.


Also, concomitant administration of quinolones with products containing iron, multivitamins containing zinc, or Videx (didanosine) chewable/buffered tablets or the pediatric powder for oral solution may result in low urine levels.


However, the systemic administration of some quinolones has been shown to elevate plasma concentrations of theophylline, interfere with the metabolism of caffeine, and enhance the effects of the oral anticoagulant warfarin and its derivatives, and has been associated with transient elevations in serum creatinine in patients receiving systemic cyclosporine concomitantly.


Drug Interactions with Beta-Blockers: Concomitant use of fenoldopam with beta-blockers should be avoided.


Drugs that reportedly may increase oral anticoagulant response, ie, increased prothrombin response, in man include:alcohol*;allopurinol;aminosalicylic acid;amiodarone;anabolic steroids;antibiotics;bromelains;chloral hydrate*;chlorpropamide;chymotrypsin;cimetidine;cinchophen;clofibrate;dextran;dextrothyroxine;diazoxide;dietary deficiencies;diflunisal;disulfiram;drugs affecting blood elements;ethacrynic acid;fenoprofen;glucagon;hepatotoxic drugs;ibuprofen;indomethacin;influenza virus vaccine;inhalation anesthetics;mefenamic acid;methyldopa;methylphenidate;metronidazole;miconazole;monoamine oxidase inhibitors;nalidixic acid;naproxen;oxolinic acid;oxyphenbutazone;pentoxifylline;phenylbutazone;phenyramidol;phenytoin;prolonged hot weather;prolonged narcotics;pyrazolones;quinidine;quinine;ranitidine*;salicylates;sulfinpyrazone;sulfonamides, long acting;sulindac;thyroid drugs;tolbutamide;triclofos sodium;trimethoprim/sulfamethoxazole;unreliable prothrombin time determinations;warfarin sodium overdosage.


Concomitant administration of Norpace and quinidine resulted in slight increases in plasma disopyramide levels and slight decreases in plasma quinidine levels.


Probenecid: As with other b-lactam antibiotics, renal excretion of loracarbef is inhibited by probenecid and resulted in an approximate 80% increase in the AUC for loracarbef.


In a comparison of digitalis tolerance in dogs anesthetized with ketamine, Innovar Vet, or pentobarbital, the dosage of ouabain needed to cause ventricular tachycardia was significantly higher, as was the LD50 of ouabain, with ketamine or Innovar than with pentobarbital.


The following are examples of substances that may increase the blood-glucose-lowering effect and susceptibility to hypoglycemia: oral antidiabetic products, ACE inhibitors, disopyramide, fibrates, fluoxetine, monoamine oxidase (MAO) inhibitors, propoxyphene, salicylates, somatostatin analog (e.g., octreotide), sulfonamide antibiotics.


Corticosteroids may also potentiate the replication of some organisms contained in live attenuated vaccines.


Tell your doctor if you are taking any of the following drugs: blood thinners (Coumadin) other antidepressants metoprolol antihistamines carbamazepine (Tegretol) cimetidine (Tagamet) estrogens fluoxetine (Prozac) intraconazole (Sporanox) ketoconazole (Nizoral) levodopa lithium muscle relaxants birth control pills sleeping pills thyroid medications


Furosemide may add to or potentiate the therapeutic effect of other antihypertensive drugs.


Benzylpenicillin, ampicillin, oxacillin, chlortetracycline, doxycycline, cephalothin, erythromycin, and sulfamethoxazole have no influence in vitro on the protein binding of diclofenac in human serum.


Pretreatment of rats with allopurinol (100 mg/kg, ip) or Vitamin E (100 mg/kg per day, ig, for 3 days and a dose of 40 mg/kg on the 4th day) provided significant protection against the elevation of TBARS levels in cerebral and hepatic tissues, induced by single high dose of oral cypermethrin administration within 4 h.


ISUPREL should be used with caution, if at all, when potent inhalational anesthetics such as halothane are employed because of potential to sensitize the myocardium to effects of sympathomimetic amines.


Antacids and kaolin: Antacids and kaolin can reduce absorption of chloroquine;


Other concomitant therapy Although specific interaction studies were not performed, finasteride doses of 1 mg or more were concomitantly used in clinical studies with acetaminophen, acetylsalicylic acid, a-blockers, analgesics, angiotensin-converting enzyme (ACE) inhibitors, anticonvulsants, benzodiazepines, beta blockers, calcium-channel blockers, cardiac nitrates, diuretics, H2 antagonists, HMG-CoA reductase inhibitors, prostaglandin synthetase inhibitors (also referred to as NSAIDs), and quinolone anti-infectives without evidence of clinically significant adverse interactions.


Cyclosporin: Reports indicate that cyclosporine levels may be increased during concomitant treatment with allopurinol sodium for injection.


Therefore, patients without a functioning thyroid gland who are on thyroid replacement therapy may need to increase their thyroid dose if estrogens or estrogen-containing oral contraceptives are given.


These results suggest that both dexamethasone and retinyl acetate, and possibly other glucocorticoids and retinoids, may regulate the proliferation of prostate epithelium by a dose-dependent modification of the activity of insulin and EGF.


Erythromycin: In healthy individuals, plasma concentrations of atorvastatin increased approximately 40% with coadministration of atorvastatin and erythromycin, a known inhibitor of cytochrome P450 3A4.


Therefore, co-administration of clozapine with other drugs that are metabolized by this isozyme, including antidepressants, phenothiazines, carbamazepine, and Type 1C antiarrhythmics (e.g., propafenone, flecainide and encainide), or that inhibit this enzyme (e.g., quinidine), should be approached with caution.


The reddish color is due to the formation of a nonabsorbable complex between cefdinir or its breakdown products and iron in the gastrointestinal tract.


Due to a theoretical risk of a pharmacodynamic interaction, use of ergotamine-containing or ergot-type medications (like dihydroergotamine or methysergide) and FROVA within 24 hours of each other should be avoided (see  a href= frova_od.htm#CI CONTRAINDICATIONS).


The concurrent use of Robinul Injection with other anticholinergics or medications with anticholinergic activity, such as phenothiazines, antiparkinson drugs, or tricyclic antidepressants, may intensify the antimuscarinic effects and may result in an increase in anticholinergic side effects.


Effects of Erythromycin on Felbatol  The coadministration of erythromycin (1000 mg/day) for 10 days did not alter the pharmacokinetic parameters of Cmax, Cmin, AUC, CI/kg or tmax at felbamate daily doses of 3000 or 3600 mg/day in 10 otherwise healthy subjects with epilepsy.


While no in vivo drug-drug interaction studies were conducted between estazolam and inducers of CYP3A, compounds that are potent CYP3A inducers (such as carbamazepine, phenytoin, rifampin, and barbiturates) would be expected to decrease estazolam concentrations.


Concomitant use of prostaglandin synthase inhibiting drugs, eg, indomethacin, may decrease the hypotensive effects of beta blockers.


The most commonly occurring drug interactions are listed below: - Drugs that may increase plasma phenytoin concentrations include: acute alcohol intake, amiodarone, chboramphenicol, chlordiazepoxide, cimetidine, diazepam, dicumarol, disulfiram, estrogens, ethosuximide, fluoxetine, H2-antagonists, halothane, isoniazid, methylphenidate, phenothiazines, phenylbutazone, salicylates, succinimides, sulfonamides, tolbutamide, trazodone


The influence of midazolam and diazepam on antinociceptive effect of morphine (10 mg/kg), metamizol (500 mg/kg) and indomethacin (10 mg/kg) was investigated in a mouse model using the tail-flick and hot-plate tests.


Interactions for vitamin D analogues (Vitamin D2, Vitamin D3, Calcitriol, and Calcidiol): Cholestyramine: Cholestyramine has been reported to reduce intestinal absorption of fat soluble vitamins;


Physostigmine pretreatment augmented the depressant effect of alcohol on the early components P1 and N1, while attenuating alcohol's influence on components P2 and P3.


Thyroid Physiology: The following agents may alter thyroid hormone or TSH levels, generally by effects on thyroid hormone synthesis, secretion, distribution, metabolism, hormone action, or elimination, or altered TSH secretion: aminoglutethimide, p-aminosalicylic acid, amiodarone, androgens and related anabolic hormones, complex anions (thiocyanate, perchlorate, pertechnetate), antithyroid drugs, b-adrenergic blocking agents, carbamazepine, chloral hydrate, diazepam, dopamine and dopamine agonists, ethionamide, glucocorticoids, heparin, hepatic enzyme inducers, insulin, iodinated cholestographic agents, iodine-containing compounds, levodopa, lovastatin, lithium, 6-mercaptopurine, metoclopramide, mitotane, nitroprusside, phenobarbital, phenytoin, resorcinol, rifampin, somatostatin analogs, sulfonamides, sulfonylureas, thiazide diuretics.


FLEXERIL may enhance the effects of alcohol, barbiturates, and other CNS depressants.


Corticosteroids: A relationship of functional antagonism exists between vitamin D analogues, which promote calcium absorption, and corticosteroids, which inhibit calcium absorption.


Quinolones, including norfloxacin, may enhance the effects of oral anticoagulants, including warfarin or its derivatives or similar agents.


Concomitant administration of rifampin with ketoconazole tablets reduces the blood levels of the latter.


Dexbrompheniramine can interact with alcohol or other CNS depressants (may potentiate the CNS depressant effects of either these medications or antihistamines), anticholinergics or other medications with anticholinergic activity (anticholinergic effects may be potentiated when these medications are used concurrently with antihistamines), and monoamine oxidase (MAO) inhibitors (concurrent use with antihistamines may prolong and intensify the anticholinergic and CNS depressant effects of antihistamines).


Phenytoin: Isoniazid may increase serum levels of phenytoin.


acetaminophen/theophylline, lidocaine/quinidine, phenobarbital/acetaminophen, phenobarbital/valproic acid, quinidine/lidocaine, theophylline/acetaminophen, and valproic acid/phenobarbital.


Potential for ABILIFY to Affect Other Drugs Aripiprazole is unlikely to cause clinically important pharmacokinetic interactions with drugs metabolized by cytochrome P450 enzymes.


Agents that have been found, or are expected to have decreased plasma levels in the presence of EQUETROTM due to induction of CYP enzymes are the following: Acetaminophen, alprazolam, amitriptyline, bupropion, buspirone, citalopram, clobazam, clonazepam, clozapine, cyclosporin, delavirdine, desipramine, diazepam, dicumarol, doxycycline, ethosuximide, felbamate, felodipine, glucocorticoids, haloperidol, itraconazole, lamotrigine, levothyroxine, lorazepam, methadone, midazolam, mirtazapine, nortriptyline, olanzapine, oral contraceptives(3), oxcarbazepine, Phenytoin(4), praziquantel, protease inhibitors, quetiapine, risperidone, theophylline, topiramate, tiagabine, tramadol, triazolam, valproate, warfarin(5) , ziprasidone, and zonisamide.


Agents that are CYP3A4 inhibitors that have been found, or are expected, to increase plasma levels of EQUETROTM are the following: Acetazolamide, azole antifungals, cimetidine, clarithromycin(1), dalfopristin, danazol, delavirdine, diltiazem, erythromycin(1), fluoxetine, fluvoxamine, grapefruit juice, isoniazid, itraconazole, ketoconazole, loratadine, nefazodone, niacinamide, nicotinamide, protease inhibitors, propoxyphene, quinine, quinupristin, troleandomycin, valproate(1), verapamil, zileuton.


Digitalis: Vitamin D dosage must be determined with care in patients undergoing treatment with digitalis, as hypercalcemia in such patients may precipitate cardiac arrhythmias.


Other drugs which may enhance the neuromuscular blocking action of nondepolarizing agents such as NIMBEX include certain antibiotics (e. g., aminoglycosides, tetracyclines, bacitracin, polymyxins, lincomycin, clindamycin, colistin, and sodium colistemethate), magnesium salts, lithium, local anesthetics, procainamide, and quinidine.


The gastrointestinal absorption of cimetidine and ranitidine is accelerated when they are coadministered with cisapride.


Because Nalfon has not been shown to produce any additional effect beyond that obtained with aspirin alone and because aspirin increases the rate of excretion of Nalfon, the concomitant use of Nalfon and salicylates is not recommended.


Itraconazole Ketoconazole Erythromycin Clarithromycin Telithromycin HIV protease inhibitors Nefazodone Cyclosporine Large quantities of grapefruit juice ( 1 quart daily)


If antacid therapy is needed, the antacid dose should be administered at least 2 hours prior to or 2 hours after the dose of SPRYCEL.


Compounds in these categories result in a decreased efficacy of bromocriptine mesylate: phenothiazines, haloperidol, metoclopramide, pimozide.


The response to Factrel may be blunted by phenothiazines and dopamine antagonists which cause a rise in prolactin.


Use lowest possible dose of atorvastatin with careful monitoring, or consider HMG-CoA reductase inhibitors that are not primarily metabolized by CYP3A4, such as pravastatin, fluvastatin, or rosuvastatin in combination with CRIXIVAN.


Concomitant administration of diltiazem with carbamazepine has been reported to result in elevated serum levels of carbamazepine (40% to 72% increase), resulting in toxicity in some cases.


Boric acid may interact with the idoxuridine preparation causing a gritty substance to form or may interact with the preservative in the idoxuridine preparation causing a toxic effect in the eye.


H2 Blockers/Proton Pump Inhibitors: Long-term suppression of gastric acid secretion by H2 blockers or proton pump inhibitors (eg, famotidine and omeprazole) is likely to reduce dasatinib exposure.


In a study in which the 2 mg clonazepam orally disintegrating tablet was administered with and without propantheline (an anticholinergic agent with multiple effects on the GI tract) to healthy volunteers, the AUC of clonazepam was 10% lower and the Cmax of clonazepam was 20% lower when the orally disintegrating tablet was given with propantheline compared to when it was given alone.


Dopamine Antagonists: Since apomorphine is a dopamine agonist, it is possible that dopamine antagonists, such as the neuroleptics (phenothiazines, butyrophenones, thioxanthenes) or metoclopramide, may diminish the effectiveness of APOKYN.


Additional reductions in blood pressure may occur when FLOLAN is administered with diuretics, antihypertensive agents, or other vasodilators.


Studies showed that diltiazem increased the AUC of midazolam and triazolam by 3-4 fold and the Cmax by 2-fold, compared to placebo.


1- adrenergic receptor antagonism, aripiprazole has the potential to enhance the effect of certain antihypertensive agents.


Midazolam used at doses of 1.25 mg/kg and 2.5 mg/kg decreased the antinociceptive effect of morphine, metamizol (only in the tail-flick test) and indomethacin.


In monkeys, the effects of (-)-NANM, but not (+)-NANM or PCP, were antagonized by naloxone;


The following are examples of drugs known to inhibit the metabolism of other related benzodiazepines, presumably through inhibition of CYP3A: nefazodone, fluvoxamine, cimetidine, diltiazem, isoniazide, and some macrolide antibiotics.


[Stimulation by cerulein--an analog of the octapeptide cholecystokinin--of 3H-spiroperidol binding after the long-term administration of neuroleptics] It has been established in experiments on white male rats that prolonged administration (twice a day for 14 days) of haloperidol (0.25 mg/kg) and pyreneperone (0.25 mg/kg) resulted in the reduced interaction between 3H-spiroperidol and low affinity binding sites for apomorphine in subcortical structures, whereas 3H-spiroperidol binding with high affinity binding sites for apomorphine increased both in the frontal cortex and subcortical structures of the forebrain.


Cytosine arabinoside, a cytostatic agent, has been reported to inactivate the antifungal activity of flucytosine by competitive inhibition.


Effects of Other Antiepileptic Drugs on Felbatol  Phenytoin: Phenytoin causes an approximate doubling of the clearance of Felbatol  (felbamate) at steady state and, therefore, the addition of phenytoin causes an approximate 45% decrease in the steady-state trough concentrations of Felbatol  as compared to the same dose of Felbatol  given as monotherapy.


Potential for reduction in anticonvulsant and/or efavirenz plasma levels;


Antidepressants: In vitro data indicate that nefazodone inhibits the metabolism of cisapride, which can result in an increase in plasma cisapride levels and prolongation of the QT interval on the ECG.


Certain antibiotic, cisplatin, cyclosporine, diuretic, foscarnet, and vaccines.


Prednisolone: Ethinyl estradiol may inhibit the metabolism of prednisolone, leading to increased plasma concentrations.


Drugs that reportedly may increase oral anticoagulant response, ie, increased prothrombin response, in man include:alcohol*;allopurinol;aminosalicylic acid;amiodarone;anabolic steroids;antibiotics;bromelains;chloral hydrate*;chlorpropamide;chymotrypsin;cimetidine;cinchophen;clofibrate;dextran;dextrothyroxine;diazoxide;dietary deficiencies;diflunisal;disulfiram;drugs affecting blood elements;ethacrynic acid;fenoprofen;glucagon;hepatotoxic drugs;ibuprofen;indomethacin;influenza virus vaccine;inhalation anesthetics;mefenamic acid;methyldopa;methylphenidate;metronidazole;miconazole;monoamine oxidase inhibitors;nalidixic acid;naproxen;oxolinic acid;oxyphenbutazone;pentoxifylline;phenylbutazone;phenyramidol;phenytoin;prolonged hot weather;prolonged narcotics;pyrazolones;quinidine;quinine;ranitidine*;salicylates;sulfinpyrazone;sulfonamides, long acting;sulindac;thyroid drugs;tolbutamide;triclofos sodium;trimethoprim/sulfamethoxazole;unreliable prothrombin time determinations;warfarin sodium overdosage.


or with multivitamins containing zinc may substantially interfere with drug absorption and result in insufficient plasma and tissue quinolone concentrations.


Cholestyramine and Charcoal Administration of cholestyramine or activated charcoal in patients (n=13) and volunteers (n=96) resulted in a rapid and significant decrease in plasma M1 (the active metabolite of leflunomide) concentration .


Erythromycin and clarithromycin (and possibly other macrolide antibiotics) and tetracycline may increase digoxin absorption in patients who inactivate digoxin by bacterial metabolism in the lower intestine, so that digitalis intoxication may result.


There have been a number of reports in the post-marketing experience of coma and death associated with the concomitant intravenous misuse of buprenorphine and benzodiazepines by addicts.


MAO Inhibitors: Studies in animals demonstrate that the acute toxicity of bupropion is enhanced by the MAO inhibitor phenelzine .


Cypermethrin-induced oxidative stress in rat brain and liver is prevented by vitamin E or allopurinol.


Avoid the concomitant use of chlorprothixene and tramadol (Ultram).


cimetidine) and many that are substrates for P450 2D6 (many other antidepressants, phenothiazines, and the Type 1C antiarrhythmics propafenone and flecainide).


However, there has been one report of prolonged prothrombin time when buspirone was added to the regimen of a patient treated with warfarin.


Other drugs which may enhance the neuromuscular blocking action of nondepolarizing agents such as NUROMAX include certain antibiotics (e. g., aminoglycosides, tetracyclines, bacitracin, polymyxins, lincomycin, clindamycin, colistin, and sodium colistimethate), magnesium salts, lithium, local anesthetics, procainamide, and quinidine.


Indinavir concentrations may be decreased in the presence of nevirapine.


Bosentan is also expected to reduce plasma concentrations of other statins that have significant metabolism by CYP3A4, such as lovastatin and atorvastatin.


Tablets, Injection, and Oral Solution One study in six subjects demonstrated that the combination of furosemide and acetylsalicylic acid temporarily reduced creatinine clearance in patients with chronic renal insufficiency.


WelChol  decreased the Cmax and AUC of sustained-release verapamil (Calan SR ) by approximately 31% and 11%, respectively.


Agents that have been found, or are expected to have decreased plasma levels in the presence of EQUETROTM due to induction of CYP enzymes are the following: Acetaminophen, alprazolam, amitriptyline, bupropion, buspirone, citalopram, clobazam, clonazepam, clozapine, cyclosporin, delavirdine, desipramine, diazepam, dicumarol, doxycycline, ethosuximide, felbamate, felodipine, glucocorticoids, haloperidol, itraconazole, lamotrigine, levothyroxine, lorazepam, methadone, midazolam, mirtazapine, nortriptyline, olanzapine, oral contraceptives(3), oxcarbazepine, Phenytoin(4), praziquantel, protease inhibitors, quetiapine, risperidone, theophylline, topiramate, tiagabine, tramadol, triazolam, valproate, warfarin(5) , ziprasidone, and zonisamide.


Etonogestrel may interact with the following medications: acetaminophen (Tylenol), antibiotics such as ampicillin and tetracycline, anticonvulsants (Dilantin, Phenobarbital, Tegretol, Trileptal, Topamax, Felbatol), antifungals (Gris-PEG, Nizoral, Sporanox), atorvastatin (Lipitor), clofibrate (Atromid-S), cyclosporine (Neoral, Sandimmune), HIV drugs classified as protease inhibitors (Agenerase, Crixivan, Fortovase, Invirase, Kaletra, Norvir, Viracept), morphine (Astramorph, Kadian, MS Contin), phenylbutazone, prednisolone (Prelone), rifadin (rifampin), St. Johns wort, temazepam, theophylline (Theo-Dur), and vitamin C.


Agents that are CYP inducers that have been found, or are expected, to decrease plasma levels of EQUETROTM are the following: Cisplatin, doxorubicin HCL, felbamate, rifampin, phenobarbital, Phenytoin(2), primidone, methsuximide, and theophylline Thus, if a patient has been titrated to a stable dosage on EQUETROTM, and then begins a course of treatment with one of these CYP3A4 inducers, it is reasonable to expect that a dose increase for EQUETROTM may be necessary.


Drugs that reportedly may increase oral anticoagulant response, ie, increased prothrombin response, in man include:alcohol*;allopurinol;aminosalicylic acid;amiodarone;anabolic steroids;antibiotics;bromelains;chloral hydrate*;chlorpropamide;chymotrypsin;cimetidine;cinchophen;clofibrate;dextran;dextrothyroxine;diazoxide;dietary deficiencies;diflunisal;disulfiram;drugs affecting blood elements;ethacrynic acid;fenoprofen;glucagon;hepatotoxic drugs;ibuprofen;indomethacin;influenza virus vaccine;inhalation anesthetics;mefenamic acid;methyldopa;methylphenidate;metronidazole;miconazole;monoamine oxidase inhibitors;nalidixic acid;naproxen;oxolinic acid;oxyphenbutazone;pentoxifylline;phenylbutazone;phenyramidol;phenytoin;prolonged hot weather;prolonged narcotics;pyrazolones;quinidine;quinine;ranitidine*;salicylates;sulfinpyrazone;sulfonamides, long acting;sulindac;thyroid drugs;tolbutamide;triclofos sodium;trimethoprim/sulfamethoxazole;unreliable prothrombin time determinations;warfarin sodium overdosage.


Concomitant administration of Mefloquine and other related compounds (eg, quinine, quinidine and chloroquine) may produce electrocardiographic abnormalities and increase the risk of convulsions.


Thyroid Physiology: The following agents may alter thyroid hormone or TSH levels, generally by effects on thyroid hormone synthesis, secretion, distribution, metabolism, hormone action, or elimination, or altered TSH secretion: aminoglutethimide, p-aminosalicylic acid, amiodarone, androgens and related anabolic hormones, complex anions (thiocyanate, perchlorate, pertechnetate), antithyroid drugs, b-adrenergic blocking agents, carbamazepine, chloral hydrate, diazepam, dopamine and dopamine agonists, ethionamide, glucocorticoids, heparin, hepatic enzyme inducers, insulin, iodinated cholestographic agents, iodine-containing compounds, levodopa, lovastatin, lithium, 6-mercaptopurine, metoclopramide, mitotane, nitroprusside, phenobarbital, phenytoin, resorcinol, rifampin, somatostatin analogs, sulfonamides, sulfonylureas, thiazide diuretics.


These drugs include the thiazides and other diuretics, corticosteroids, phenothiazines, thyroid products, estrogens, oral contraceptives, phenytoin, nicotinic acid, sympathomimetics, calcium channel-blocking drugs, and isoniazid.


Monitoring of liver enzymes is recommended when SUSTIVA is used in combination with ritonavir.


Conjugation at NaCMC with cysteine moieties significantly improves the intestinal permeation of the hydrophilic molecule NaFlu and the model peptide drugs bacitracin and insulin in vitro, therefore this conjugated system maybe useful for peroral administration of peptide drugs in the future.


CONCLUSIONS: Macrolide antibiotics inhibit the metabolism of HMG-CoA reductase inhibitors that are metabolized by CYP3A4 (i.e., atorvastatin, cerivastatin, lovastatin, simvastatin).


Drugs that have been reported to diminish oral anticoagulant response, ie, decreased prothrom-bin time response, in man significantly include: adrenocortical steroids;alcohol*;antacids;antihistamines;barbiturates;carbamazepine;chloral hydrate*;chlordiazepoxide;cholestyramine;diet high in vitamin K;diuretics*;ethchlorvynol;glutethimide;griseofulvin;haloperidol;meprobamate;oral contraceptives;paraldehyde;primidone;ranitidine*;rifampin;unreliable prothrombin time determinations;vitamin C;warfarin sodium under-dosage.


Quinolones have also been shown to interfere with the metabolism of caffeine.


Administration of diltiazem hydrochloride with digoxin in 24 healthy male subjects increased plasma digoxin concentrations approximately 20%.


Other drugs Drug interactions have been reported with concomitant administration of erythromycin and other medications, including cyclosporine, hexobarbital, carbamazepine, alfentanil, disopyramide, phenytoin, bromocriptine, valproate, astemizole, and lovastatin.


Thus, the results suggest that cypermethrin exposure of rats results in free radical-mediated tissue damage, as indicated by elevated cerebral and hepatic lipid peroxidation, which was prevented by allopurinol and Vitamin E.


Central nervous system depressant (CNS) drugs including alcohol, antidepressants, antihistamines, antipsychotics, blood pressure medications (reserpine, methyldopa, beta-blockers), motion sickness medications, muscle relaxants, narcotics, sedatives, sleeping pills and tranquilizers


Thus patients receiving oral anticoagulants and Fluvoxamine Tablets should have their prothrombin time monitored and their anticoagulant dose adjusted accordingly.


d-amphetamine with desipramine or protriptyline and possibly other tricyclics cause striking and sustained increases in the concentration of d-amphetamine in the brain;


Drug Interactions: The central anticholinergic syndrome can occur when anticholinergic agents such as AKINETON are administered concomitantly with drugs that have secondary anticholinergic actions, e.g., certain narcotic analgesics such as meperidine, the phenothiazines and other antipsychotics, tricyclic antidepressants, certain antiarrhythmics such as the quinidine salts, and antihistamines.


INDOCIN and triamterene should not be administered together.


Before taking glimepiride, tell your doctor if you are taking any of the following medicines: - aspirin or another salicylate such as magnesium/choline salicylate (Trilisate), salsalate (Disalcid, others), choline salicylate (Arthropan), magnesium salicylate (Magan), or bismuth subsalicylate (Pepto-Bismol);


Etonogestrel may interact with the following medications: acetaminophen (Tylenol), antibiotics such as ampicillin and tetracycline, anticonvulsants (Dilantin, Phenobarbital, Tegretol, Trileptal, Topamax, Felbatol), antifungals (Gris-PEG, Nizoral, Sporanox), atorvastatin (Lipitor), clofibrate (Atromid-S), cyclosporine (Neoral, Sandimmune), HIV drugs classified as protease inhibitors (Agenerase, Crixivan, Fortovase, Invirase, Kaletra, Norvir, Viracept), morphine (Astramorph, Kadian, MS Contin), phenylbutazone, prednisolone (Prelone), rifadin (rifampin), St. Johns wort, temazepam, theophylline (Theo-Dur), and vitamin C.


Drugs that reportedly may increase oral anticoagulant response, ie, increased prothrombin response, in man include:alcohol*;allopurinol;aminosalicylic acid;amiodarone;anabolic steroids;antibiotics;bromelains;chloral hydrate*;chlorpropamide;chymotrypsin;cimetidine;cinchophen;clofibrate;dextran;dextrothyroxine;diazoxide;dietary deficiencies;diflunisal;disulfiram;drugs affecting blood elements;ethacrynic acid;fenoprofen;glucagon;hepatotoxic drugs;ibuprofen;indomethacin;influenza virus vaccine;inhalation anesthetics;mefenamic acid;methyldopa;methylphenidate;metronidazole;miconazole;monoamine oxidase inhibitors;nalidixic acid;naproxen;oxolinic acid;oxyphenbutazone;pentoxifylline;phenylbutazone;phenyramidol;phenytoin;prolonged hot weather;prolonged narcotics;pyrazolones;quinidine;quinine;ranitidine*;salicylates;sulfinpyrazone;sulfonamides, long acting;sulindac;thyroid drugs;tolbutamide;triclofos sodium;trimethoprim/sulfamethoxazole;unreliable prothrombin time determinations;warfarin sodium overdosage.


Animal studies indicate that dobutamine may be ineffective if the patient has recently received a b-blocking drug.


Animals dosed with 1,3-difluoroacetone did not display the 2-3 hour lag phase in either (-)-erythro-fluorocitrate synthesis or in citrate and fluoride accumulation characteristic of animals dosed with 1,3-difluoro-2-propanol.


Fluconazole: Concomitant administration of fluconazole at 200 mg QD resulted in a two-fold increase in celecoxib plasma concentration.


However, because bleeding has been reported when ibuprofen and other nonsteroidal anti-inflammatory agents have been administered to patients on coumarin-type anticoagulants, the physician should be cautious when administering ibuprofen to patients on anticoagulants.


However, prudent medical practice dictates careful monitoring of prothrombin time in all patients treated with azithromycin and warfarin concomitantly.


Warfarin Keppra  (1000 mg twice daily) did not influence the pharmacokinetics of R and S warfarin.


Aspirin: Concomitant administration of diclofenac and aspirin is not recommended because diclofenac is displaced from its binding sites during the concomitant administration of aspirin, resulting in lower plasma concentrations, peak plasma levels, and AUC values.


Caution should be observed when anileridine is coadministered with other opioids, sedatives, phenothiazines, or anesthetics, as these agents may increase respiratory and circulatory depression.


In addition, olanzapine is not associated with a risk of agranulocytosis as seen with clozapine or clinically significant hyperprolactinaemia as seen with risperidone or prolongation of the QT interval.


Coadministration of alosetron and strong CYP3A4 inhibitors, such as clarithromycin, telithromycin, protease inhibitors, voriconazole, and itraconazole has not been evaluated but should be undertaken with caution because of similar potential drug interactions.


Nabilone should be administered with caution to patients who are taking other psychoactive drugs or CNS depressants, including alcohol, barbiturates and narcotic analgesics, or to those with a history of psychiatric disorder (including manic-depressive illness and schizophrenia).


Steroids enhance the renal toxicity of edetate calcium disodium in animals. 7 Edetate calcium disodium interferes with the action of zinc insulin preparations by chelating the zinc. 7


Drugs that have been reported to diminish oral anticoagulant response, ie, decreased prothrom-bin time response, in man significantly include: adrenocortical steroids;alcohol*;antacids;antihistamines;barbiturates;carbamazepine;chloral hydrate*;chlordiazepoxide;cholestyramine;diet high in vitamin K;diuretics*;ethchlorvynol;glutethimide;griseofulvin;haloperidol;meprobamate;oral contraceptives;paraldehyde;primidone;ranitidine*;rifampin;unreliable prothrombin time determinations;vitamin C;warfarin sodium under-dosage.


Although additional drug interaction studies have not been conducted, the most common medications used concomitantly with anagrelide in clinical trials were aspirin, acetaminophen, furosemide, iron, ranitidine, hydroxyurea, and allopurinol.


On the other hand, intrathecal naloxone (12-120 micrograms) had only a very weak effect on the tail-flick inhibition induced by intraventricular morphine (40 micrograms).


Drugs That Should Not Be Coadministered With VIRACEPT Antiarrhythmics: amiodarone, quinidine Antihistamines: astemizole, terfenadine Antimigraine: ergot derivatives Antimycobacterial agents: rifampin Benzodiazepines midazolam, triazolam GI motility agents: cisapride


Dexfenfluramine should not be administered with other serotoninergic agents.


propranolol to healthy volunteers under steady-state conditions had no relevant effect on either drug s bioavailability, AUC and Cmax, differences were  20% between isradipine given singly and in combination with propranolol, and between propranolol given singly and in combination with isradipine.


Caution should be exercised when administering nabumetone with warfarin since interactions have been seen with other NSAIDs.


Although a causal mechanism and a cause-and-effect relationship have not been established, current evidence suggests that renal function should be monitored in patients on thiazide diuretics and allopurinol even in the absence of renal failure, and dosage levels should be even more conservatively adjusted in those patients on such combined therapy if diminished renal function is detected..


Sulfapyridine may interact with any of the following: - Acetaminophen (e.g., Tylenol) (with long-term, high-dose use) or


Magnesium: Magnesium-containing preparations (eg, antacids) may cause hypermagnesemia and should therefore not be taken during therapy with vitamin D by patients on chronic renal dialysis.


The hypoglycemic action of sulfonylureas may be potentiated by certain drugs including nonsteroidal anti-inflammatory agents and other drugs that are highly protein bound, salicylates, sulfonamides, chloramphenicol, probenecid, coumarins, monoamine oxidase inhibitors, and beta adrenergic blocking agents.


Phenytoin: In post-marketing experience, there have been reports of both increases and decreases in phenytoin levels with dexamethasone co-administration, leading to alterations in seizure control.


Magnesium- and/or aluminum-containing antacids, products containing ferrous sulfate (iron), multivitamin preparations containing zinc or other metal cations, or Videx (didanosine) chewable/buffered tablets or the pediatric powder for oral solution should not be taken within 3 hours before or 2 hours after FACTIVE.


While not systematically studied, certain drugs may induce the metabolism of bupropion (e.g., carbamazepine, phenobarbital, phenytoin).


The effect of rifampin on the warfarin requirement of our patient appeared to be maximal 5 to 7 days after the initiation of rifampin and extended a similar length of time after rifampin withdrawal.


Concurrent administration of dyphylline and probenecid, which competes for tubular secretion, has been shown to increase the plasma half-life of dyphylline .


Bacteriostatic Antibiotics: Chloramphenicol, erythromycins, sulfonamides, or tetracyclines may interfere with the bactericidal effect of penicillins.


Other drugs Drug interactions have been reported with concomitant administration of erythromycin and other medications, including cyclosporine, hexobarbital, carbamazepine, alfentanil, disopyramide, phenytoin, bromocriptine, valproate, astemizole, and lovastatin.