Patients on lithium treatment should be closely monitored when CELEBREX is introduced or withdrawn.


On the basis of the metabolism of bexarotene by cytochrome P450 3A4, ketoconazole, itraconazole, erythromycin, gemfibrozil, grapefruit juice, and other inhibitors of cytochrome P450 3A4 would be expected to lead to an increase in plasma bexarotene concentrations.


Caution should be used when administering or taking TARCEVA with ketoconazole and other strong CYP3A4 inhibitors such as, but not limited to, atazanavir, clarithromycin, indinavir, itraconazole, nefazodone, nelfinavir, ritonavir, saquinavir, telithromycin, troleandomycin (TAO), and voriconazole .


Similarly, diazepam decreased the antinociceptive effect of metamizol (only in the tail-flick test) and indomethacin.


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


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.


It was shown that neurotensin antagonized evidently the antinociceptive effect of enkephalins and their analogue.


Non-steroidal Anti-inflammatory Drugs: In some patients, the administration of a non-steroidal anti-inflammatory agent can reduce the diuretic, natriuretic, and antihypertensive effects of loop, potassium-sparing and thiazide diuretics.


This interaction, which has not been investigated using higher doses of fluvoxamine, may be more pronounced if a 300 mg daily dose is co-administered, particularly since fluvoxamine exhibits non-linear pharmacokinetics over the dosage range 100-300 mg. If alprazolam is co-administered with Fluvoxamine Tablets, the initial alprazolam dosage should be at least halved and titration to the lowest effective dose is recommended.


In vitro displacement studies with highly protein-bound drugs such as furosemide, propranolol, captopril, nicardipine, pravastatin, glyburide, warfarin, phenytoin, acetylsalicylic acid, tolbutamide, and metformin showed no influence on the extent of nateglinide protein binding.


Ketoconazole: Ketoconazole may inhibit both synthetic and catabolic enzymes of vitamin D.


The purpose of this study was to evaluate the effect of sodium carboxymethylcellulose (NaCMC) and carboxymethylcellulose-cysteine (CMC-Cys) conjugates on the intestinal permeation of sodium fluorescein (NaFlu) and model peptide drugs, bacitracin and insulin.


Antacids containing aluminum hydroxide and magnesium hydroxide reduce the oral absorption of enoxacin by 75%.


Patients on rifampin should receive 70 mg of CANCIDAS daily.


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.


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.


Hormonal contraceptives Co-administration of Trileptal with an oral contraceptive has been shown to influence the plasma concentrations of the two hormonal components, ethinylestradiol (EE) and levonorgestrel (LNG).


Skeletal muscle relaxants: amphotericin B-induced hypokalemia may enhance the curariform effect of skeletal muscle relaxants (e.g., tubocurarine).


Nephrotoxicity has been reported following concomitant administration of other cephalosporins with potent diuretics such as furosemide.


Patients receiving other narcotic analgesics, antipsychotics, antianxiety agents, or other CNS depressants (including alcohol) concomitantly with hydrocodone and acetaminophen tablets may exhibit an additive CNS depression.


Concurrent administration of a TNF antagonist with ORENCIA has been associated with an increased risk of serious infections and no significant additional efficacy over use of the TNF antagonists alone.


Serious cardiac dysrhythmias, some resulting in death, have occurred in patients receiving terfenadine concomitantly with other macrolide antibiotics.


The action of the benzodiazepines may be potentiated by anticonvulsants, antihistamines, alcohol, barbiturates, monoamine oxidase inhibitors, narcotics, phenothiazines, psychotropic medications, or other drugs that produce CNS depression.


It is concluded that neurotensin modulates in an opposite way the function of the enkephalinergic neurons and the central action of tuftsin.


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


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;


Because moderate CYP3A4 inhibitors (e.g., diltiazem) result in 2-fold increase in plasma concentrations of aprepitant, concomitant administration should also be approached with caution.


Naproxen, naproxen sodium and other NSAIDs have been reported to reduce the tubular secretion of methotrexate in an animal model, possibly increasing the toxicity of methotrexate.


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.


However, the antagonism of the theophylline-induced anxiogenic effects by CGS21680 was only observed in the time spent in the light zone, and DPCPX-induced anxiogenic effects were neither reversed by CGS 21680 nor by CPA.


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.


A rare, but serious, constellation of symptoms, termed serotonin syndrome, has been reported with the concomitant use of selective serotonin reuptake inhibitors (SSRIs) and agents for migraine therapy, such as Imitrex (sumatriptan succinate) and dihydroergotamine.


Although the clinical significance of these effects is not known, caution is advised in the co-administration of beta-agonists with non-potassium sparing diuretics.


(In some patients, the steroidal anti-inflammatory agent can reduce the diuretic, natriuretic, and antihypertensive effects of loop, potassium sparing, and thiazide diuretics.


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.


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.


If NovoLog is mixed with NPH human insulin, NovoLog should be drawn into the syringe first.


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 effects of medicinal products with similar properties such as inotropes milrinone, enoximone, amrinone, olprinone and cilostazol may be exacerbated by anagrelide.


Medications can interfere with folate utilization, including: anticonvulsant medications (such as phenytoin, and primidone) metformin (sometimes prescribed to control blood sugar in type 2 diabetes) sulfasalazine (used to control inflammation associated with Crohns disease and ulcerative colitis) triamterene (a diuretic) Methotrexate There has been concern about the interaction between vitamin B12 and folic acid.


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.


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.


Triazolam: Erythromycin has been reported to decrease the clearance of triazolam and, thus, may increase the pharmacologic effect of triazolam.


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.


Indinavir has been shown to increase plasma levels of combination hormonal contraceptives.


Other Drugs: In healthy volunteers, amlodipine, phenytoin, glyburide, ranitidine, omeprazole, hormone replacement therapy (a combination of conjugated estrogens and medroxyprogesterone), antacid (aluminum and magnesium hydroxides) and theophylline did not affect the pharmacokinetics of TIKOSYN.


Concurrent administration of drugs possessing nephrotoxic (e.g., aminoglycosides, indomethacin), myelotoxic (e.g., cytotoxic chemotherapy), cardiotoxic (e.g., doxorubicin) or hepatotoxic (e.g., methotrexate, asparaginase) effects with PROLEUKIN may increase toxicity in these organ systems.


Indinavir: Coadministration of indinavir with VIRACEPT resulted in an 83% increase in nelfinavir plasma AUC and a 51% increase in indinavir plasma A.C.


Thioridazine: Coadministration of single doses of Sonata 20 mg and thioridazine 50 mg produced additive effects on decreased alertness and impaired psychomotor performance for 2 to 4 hours after administration.


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);


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.


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.


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.


Particular caution is recommended when administering Gleevec with CYP3A4 substrates that have a narrow therapeutic window (e.g., cyclosporine or pimozide).


Estrogens, including oral contraceptives: Estrogens may decrease the hepatic metabolism of certain corticosteroids, thereby increasing their effect.


This could lead to decreased salicylate serum levels or increase the risk of salicylate toxicity when corticosteroid is withdrawn.


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.


Patients should be warned of the potential danger of the intravenous self-administration of benzodiazepines while under treatment with SUBOXONE or SUBUTEX.


Also, bleeding and/or increased prothrombin time have been reported in a few patients taking coumarin anticoagulants concomitantly with lovastatin.


Acetazolamide and sodium bicarbonate used concurrently increases the risk of renal calculus formation.


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.


All subjects received amprenavir (1,200 mg twice a day) for 4 days, followed by a 7-day washout period, followed by either rifabutin (300 mg once a day [QD]) (cohort 1) or rifampin (600 mg QD) (cohort 2) for 14 days.


Promethazine: Coadministration of a single dose of zaleplon and promethazine (10 and 25 mg, respectively) resulted in a 15% decrease in maximal plasma concentrations of zaleplon, but no change in the area under the plasma concentration-time curve.


This allows bitolterol to open air passages, increasing the effectiveness of the steroid.


Loperamide and morphine (0.1 and 1.0 mg/kg, s.c.) inhibited the dmPGE2 (0.3 mg/kg, p.o.)-induced diarrhea in cecectomized rats.


Hyperpyrexia has been reported when amitriptyline HCl is administered with anticholinergic agents or with neuroleptic drugs, particularly during hot weather.


Hydrochlorothiazide: In normal volunteers, concomitant administration of diflunisal and hydrochlorothiazide resulted in significantly increased plasma levels of hydrochlorothiazide.


CRIXIVAN may not be effective due to decreased indinavir concentrations in patients taking these agents concomitantly.


Tricyclic Antidepressants: Use of thyroid products with imipramine and other tricyclic antidepressants may increase receptor sensitivity and enhance antidepressant activity transient cardiac arrhythmias have been observed.


The use of Adenocard in patients receiving digitalis may be rarely associated with ventricular fibrillation.


Magnesium- and aluminum-containing antacids, administered concomitantly with lomefloxacin, significantly decreased the bioavailability (48%) of lomefloxacin.


Caution should be exercised if an HMG-CoA reductase inhibitor is administered concomitantly with drugs that may decrease the levels or activity of endogenous steroid hormones, such as ketoconazole, spironolactone, and cimetidine.


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.


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.


This interaction, which has not been investigated using higher doses of fluvoxamine, may be more pronounced if a 300 mg daily dose is co-administered, particularly since fluvoxamine exhibits non-linear pharmacokinetics over the dosage range 100-300 mg. If alprazolam is co-administered with Fluvoxamine Tablets, the initial alprazolam dosage should be at least halved and titration to the lowest effective dose is recommended.


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.


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.


The blood pressure effect of SULAR tended to be greater in patients on atenolol than in patients on no other antihypertensive therapy.


Phenobarbital: Estimates of steady-state pharmacokinetic parameters for phenobarbital or gabapentin (300 mg TID;


Patients receiving both indomethacin and furosemide should be observed closely to determine if the desired diuretic and/or antihypertensive effect of furosemide is achieved.


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.


In long surgical procedures during enflurane or isoflurane anesthesia, less frequent maintenance dosing, lower maintenance doses, or reduced infusion rates of NIMBEX may be necessary.


Pharmacokinetic data indicate that oral ketoconazole inhibits the metabolism of astemizole, resulting in elevated plasma levels of astemizole and its active metabolite desmethylastemizole which may prolong QT intervals.


Coadministration of entecavir with lamivudine, adefovir dipivoxil,or tenofovir disoproxil fumarate did not result in significant drug interactions.


Particular caution is necessary when using ROMAZICON in cases of mixed drug overdosage since the toxic effects (such as convulsions and cardiac dysrhythmias) of other drugs taken in overdose (especially cyclic antidepressants) may emerge with the reversal of the benzodiazepine effect by flumazenil.


The effects of allopurinol on didanosine pharmacokinetics in subjects with normal renal function are not known.


Inhibitors of this isoenzyme (e.g., macrolide antibiotics, azole antifungal agents, protease inhibitors, serotonin reuptake inhibitors, amiodarone, cannabinoids, diltiazem, grapefruit juice, nefazadone, norfloxacin, quinine, zafirlukast) should be cautiously coadministered with TIKOSYN as they can potentially increase dofetilide levels.


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.


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);


Platelet inhibitors: Drugs such as acetylsalicylic acid, dextran, phenylbutazone, ibuprofen, indomethacin, dipyridamole, hydroxychloroquine and others that interfere with platelet-aggregation reactions (the main hemostatic defense of heparinized patients) may induce bleeding and should be used with caution in patients receiving heparin sodium.


Literature reports suggest that oral calcium antagonists may be used in combination with beta-adrenergic blocking agents when heart function is normal, but should be avoided in patients with impaired cardiac function.


During clinical trials, iloprost was used concurrently with anticoagulants, diuretics, cardiac glycosides, calcium channel blockers, analgesics, antipyretics, nonsteroidal antiinflammatories, corticosteroids, and other medications.


Antiarrhythmics: bepridil, lidocaine (systemic) and quinidine


Although metoclopramide may increase the bioavailability of levodopa by increasing gastric emptying, metoclopramide may also adversely affect disease control by its dopamine receptor antagonistic properties.


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


Lithium carbonate: The anorectic and stimulatory effects of amphetamines may be inhibited by lithium carbonate.


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.


BROVANA, as with other beta2-agonists, should be administered with extreme caution to patients being treated with monoamine oxidase inhibitors, tricyclic antidepressants, or drugs known to prolong the QTc interval because the action of adrenergic agonists on the cardiovascular system may be potentiated by these agents.


It is recommended that if CASODEX is started in patients already receiving coumarin anticoagulants, prothrombin times should be closely monitored and adjustment of the anticoagulant dose may be necessary.


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


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


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


The steady state plasma concentrations of imipramine and desipramine have been reported to be increased an average of 31% and 20%, respectively, by the concomitant administration of alprazolam tablets in doses up to 4 mg/day.


Therefore, hormonal contraceptives, including oral, injectable, transdermal, and implantable forms, may not be reliable when TRACLEER is co-administered.


however, as with other NSAIDs, concomitant administration of Lodine and aspirin is not generally recommended because of the potential of increased adverse effects.


A rare, but serious, constellation of symptoms, termed serotonin syndrome, has been reported with the concomitant use of selective serotonin reuptake inhibitors (SSRIs) and agents for migraine therapy, such as Imitrex (sumatriptan succinate) and dihydroergotamine.


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


In simultaneous treatment with imidazole drugs and coumarin drugs, the anticoagulant effect should be carefully titrated and monitored.


Therefore, caution should be used when administering nitazoxanide concurrently with other highly plasma protein-bound drugs with narrow therapeutic indices, as competition for binding sites may occur (e.g., warfarin).


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.


It is advisable to check coagulation time within the first few days after the start and discontinuation of cisapride therapy, with an appropriate adjustment of the anticoagulant dose, if necessary.


The use of NSAIDs in patients who are receiving ACE inhibitors may potentiate renal disease states.


Although no clinical studies have been conducted, it is likely that the metabolism of levobupivacaine may be affected by the known CYP3A4 inducers (such as phenytoin, phenobarbital, rifampin), CYP3A4 inhibitors (azole antimycotics e.g., ketoconazole;


Antithyroid agents may decrease thyroidal uptake of sodium iodide I131, a rebound in uptake may occur up to 5 days after sudden withdrawal of Carbimazole.


Fenfluramine may increase slightly the effect of antihypertensive drugs, e.g., guanethidine, methyldopa, reserpine.


Inhibitors of this isoenzyme (e.g., macrolide antibiotics, azole antifungal agents, protease inhibitors, serotonin reuptake inhibitors, amiodarone, cannabinoids, diltiazem, grapefruit juice, nefazadone, norfloxacin, quinine, zafirlukast) should be cautiously coadministered with TIKOSYN as they can potentially increase dofetilide levels.


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


Coadministration of ethoxzolamide with other diuretics, amphotericin B, and corticosteroids may cause hypokalemia.


Benzodiazepines: Combination hormonal contraceptives may decrease the clearance of some benzodiazepines (alprazolam, chlordiazepoxide, diazepam) and increase the clearance of others (lorazepam, oxazepam, temazepam).


The effects of adenosine are antagonized by methylxanthines such as caffeine and theophylline.


Multivalent Cation-Containing Products: Concurrent administration of a quinolone, including ciprofloxacin, with multivalent cation-containing products such as magnesium or aluminum antacids, sucralfate, VIDEX chewable/buffered tablets or pediatric powder, or products containing calcium, iron, or zinc may substantially decrease the absorption of ciprofloxacin, resulting in serum and urine levels considerably lower than desired.


astemizole midazolam, triazolam cisapride ergot derivatives voriconazole


Digoxin, Nimodipine and Losartan: Bosentan has no significant pharmacokinetic interactions with digoxin and nimodipine, and losartan has no significant effect on plasma levels of bosentan.


FLEXERIL may have life-threatening interactions with MAO inhibitors.


While it is not known whether this interaction occurs with fibrates other than gemfibrozil, myopathy and rhabdomyolysis have occasionally been associated with the use of fibrates alone, including clofibrate.


Although not studied with alosetron, inhibition of N-acetyltransferase may have clinically relevant consequences for drugs such as isoniazid, procainamide, and hydralazine.


However, co  administration of fexofenadine hydrochloride with either ketoconazole or erythromycin led to increased plasma concentrations of fexofenadine.


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.


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) .


ERGAMISOL  (levamisole hydrochloride) has been reported to produce ANTABUSE-like side effects when given concomitantly with alcohol.


Example inhibitors include azole antifungals, ciprofloxacin, clarithromycin, diclofenac, doxycycline, erythromycin, imatinib, isoniazid, nefazodone, nicardipine, propofol, protease inhibitors, quinidine, and verapamil.


However, careful attention must be directed to cross toxicity and possible pharmacokinetic interactions between antiretroviral and antineoplastic drugs.


Codeine in combination with other narcotic analgesics, general anesthetics, phenothiazines, tranquilizers, sedative-hypnotics, or other CNS depressants (including alcohol) has additive depressant effects.


On the basis of the metabolism of bexarotene by cytochrome P450 3A4, ketoconazole, itraconazole, erythromycin, gemfibrozil, grapefruit juice, and other inhibitors of cytochrome P450 3A4 would be expected to lead to an increase in plasma bexarotene concentrations.


The treatment of ewes with an intravenous (IV) injection of trichlorfon, insufficient to produce significant inhibition of erythrocyte acetylcholinesterase (AChE) activity, appeared to produce additive effects with those produced by subsequent treatment with 4 mg of coumaphos/kg/day.


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.


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.


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.


The benzodiazepines, including alprazolam, produce additive CNS depressant effects when co-administered with other psychotropic medications, anticonvulsants, antihistaminics, ethanol, and other drugs which themselves produce CNS depression.


Bromocriptine mesylate may interact with dopamine antagonists, butyrophenones, and certain other agents.


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.


Certain drugs including thiazides, corticosteroids, thyroid products, and sympathomimetics may reduce the hypoglycemic action of Starlix and other oral antidiabetic drugs.


Concomitant medications were grouped as ACE inhibitors, oral anticoagulants, calcium channel blockers, beta blockers, cardiac glycosides, inducers of CYP3A4, substrates and inhibitors of CYP3A4, substrates and inhibitors of P-glycoprotein, nitrates, sulphonylureas, loop diuretics, potassium sparing diuretics, thiazide diuretics, substrates and inhibitors of tubular organic cation transport, and QTc-prolonging drugs.


Concurrent administration of vasopressor drugs (for the treatment of hypotension related to obstetric blocks) and ergot-type oxytocic drugs may cause severe, persistent hypertension or cerebrovascular accidents.


Antiepileptic Drugs: Sporadic cases of seizures have been reported during concomitant use of TORADOL and antiepileptic drugs (phenytoin, carbamazepine).


Alcohol: It should be borne in mind that alcohol ingestion may increase the danger inherent in any intentional or unintentional SINEQUAN overdosage.


Anticonvulsants (carbamazepine, felbamate, phenobarbital, phenytoin, topiramate): Increase the metabolism of ethinyl estradiol and/or some progestins, leading to possible decrease in contraceptive effectiveness.


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.


Ampicillin/Amoxicillin: An increase in the frequency of skin rash has been reported among patients receiving ampicillin or amoxicillin concurrently with allopurinol compared to patients who are not receiving both drugs.


Omeprazole: The rate and extent of absorption of ciprofloxacin was bioequivalent when Proquin XR was given alone or when Proquin XR was given 2 hours after omeprazole at the dose that maximally suppresses gastric acid secretion.


Antacids: Concomitant administration of antacids containing magnesium or aluminum with VIDEX Chewable/Dispersible Buffered Tablets or Pediatric Powder for Oral Solution may potentiate adverse events associated with the antacid components.


astemizole midazolam, triazolam cisapride ergot derivatives voriconazole


Higher concentrations of dexamethasone (10(-8) - 10(-6) M) or retinyl acetate (3 X 10(-8) - 10(-7) M) enhance the mitogenic activity of EGF.


Digoxin: In patients with hypercholesterolemia, concomitant administration of lovastatin and digoxin resulted in no effect on digoxin plasma concentrations.


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.


Isoflurane, enflurane, and halothane decrease the ED50 of NUROMAX by 30% to 45%.


Macrolide Antibiotics (e. g. erythromycin and troleandomycin): Agents of the ergot alkaloid class, of which D.H.E. 45  (dihydroergotamine mesylate) Injection, USP is a member, have been shown to interact with antibiotics of the macrolide class, resulting in increased plasma levels of unchanged alkaloids and peripheral vasoconstriction.


Induction of apoptosis in breast cancer cells in response to vitamin D and antiestrogens.


Lithium: Diclofenac decreases lithium renal clearance and increases lithium plasma levels.


Inhibitors of CYP1A2: Concomitant use of duloxetine with fluvoxamine, an inhibitor of CYP1A2, results in approximately a 6-fold increase in AUC and about a 2.5-fold increase in Cmax of duloxetine.


Data from in vitro studies of alprazolam suggest a possible drug interaction with alprazolam for the following: sertraline and paroxetine.


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


Other Drugs: In small groups of patients (7-10/interaction study), the concomitant administration of azathioprine, gold, chloroquine, D-penicillamine, prednisolone, doxycycline, or digitoxin did not significantly affect the peak levels and AUC values of diclofenac.


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.


Patients should be warned of the potential danger of the intravenous self-administration of benzodiazepines while under treatment with SUBOXONE or SUBUTEX.


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.


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.


In addition, oxcarbazepine and MHD induce a subgroup of the cytochrome P450 3A family (CYP3A4 and CYP3A5) responsible for the metabolism of dihydropyridine calcium antagonists and oral contraceptives, resulting in a lower plasma concentration of these drugs.


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.


Interaction of gentamycin and atracurium in anaesthetised horses.


Nucleoside Analogues Didanosine Co-administration of COPEGUS and didanosine is not recommended.


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


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.


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.


A rare, but serious, constellation of symptoms, termed serotonin syndrome, has been reported with the concomitant use of selective serotonin reuptake inhibitors (SSRIs) and agents for migraine therapy, such as Imitrex (sumatriptan succinate) and dihydroergotamine.


When administered concurrently, the following drugs may interact with beta-adrenergic receptor blocking agents: Anesthetics, general: exaggeration of the hypotension induced by general anesthetics.


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


Single doses of either cholestyramine or colestipol resins bind the hydrochlorothiazide and reduce its absorption from the gastrointestinal tract by up to 85 and 43 percent, respectively.


In a 12-month controlled trial that included a 50 mcg once daily BROVANA dose, 30 of the 528 BROVANA -treated subjects received concomitant theophylline at study entry.


Other Drugs: Based on the results of drug interaction studies, no dosage adjustment is recommended when SUSTIVA (efavirenz) is given with the following: aluminum/magnesium hydroxide antacids, azithromycin, cetirizine, famotidine, fluconazole, lamivudine, lorazepam, nelfinavir, paroxetine, and zidovudine.


In addition, under the influence of sympatholytic medicinal products such as beta-blockers, clonidine, guanethidine, and reserpine, the signs of hypoglycemia may be reduced or absent.


Pharmacokinetic studies have demonstrated that omeprazole and erythromycin significantly increased the systemic exposure of cilostazol and/or its major metabolites.


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).


however, patients with moderate to severe cardiovascular disease or those taking nitrate therapy are at increased risk for potentially serious cardiovascular adverse effects with sildenafil therapy.


Reports suggest that NSAIDs may diminish the antihypertensive effect of ACE inhibitors, including lisinopril.


Most of the above effects concerning diuretics have been attributed, at least in part, to mechanisms involving inhibition of prostaglandin synthesis by INDOCIN.


and disulfiram When amitriptyline HCl is given with anticholinergic agents or sympathomimetic drugs, including epinephrine combined with local anesthetics, close supervision and careful adjustment of dosages are required.


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


However, it has been established that acitretin interferes with the contraceptive effect of microdosed progestin minipill preparations.


Inhibitors of CYP3A4 (eg, ketoconazole) or CYP2D6 (eg, quinidine, fluoxetine, or paroxetine) can inhibit aripiprazole elimination and cause increased blood levels.


Adrenergic Agents:Some individuals receiving ZYVOX may experience a reversible enhancement of the pressor response to indirect-acting sympathomimetic agents, vasopressor or dopaminergic agents.


Ritonavir significantly prolonged the half-life of vardenafil to 26 hours.


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


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.


At 24 hours postdose, a similar proportion of patients treated with methotrexate alone (94%) and subsequently treated with methotrexate co-administered with 75 mg of rofecoxib (88%) had methotrexate plasma concentrations below the measurable limit (5 ng/mL).


Other antiarrhythmic drugs (eg, quinidine, procainamide, lidocaine, propranolol) have occasionally been used concurrently with Norpace.


Quinolone Antibiotics: VIDEX should be administered at least 2 hours after or 6 hours before dosing with ciprofloxacin because plasma concentrations of ciprofloxacin are decreased when administered with antacids containing magnesium, calcium, or aluminum.


Benzodiazepines: Combination hormonal contraceptives may decrease the clearance of some benzodiazepines (alprazolam, chlordiazepoxide, diazepam) and increase the clearance of others (lorazepam, oxazepam, temazepam).


Antihypertensive medications, other, especially diazoxide, or preanesthetic and anesthetic agents used in surgery or skeletal-muscle relaxants, nondepolarizing, used in surgery


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.


Intestinal adsorbents (e. g., charcoal) and digestive enzyme preparations containing carbohydrate-splitting enzymes (e. g., amylase, pancreatin) may reduce the effect of Acarbose and should not be taken concomitantly.


Consequently, estazolam should be avoided in patients receiving ketoconazole and itraconazole, which are very potent inhibitors of CYP3A.


Ethoxzolamide may increase the action of tricyclics, amphetamines, procainamide, and quinidine.


No interaction with the tricyclic antidepressant imipramine was shown in a single-dose study with entacapone without coadministered levodopa/dopa-decarboxylase inhibitor.


In some patients, the administration of a non-steroidal anti-inflammatory agent can reduce the diuretic, natriuretic, and antihypertensive effects of loop, potassium-sparing and thiazide diuretics.


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.


Close supervision and careful adjustment of dosage are required when Anafranil is administered with anticholinergic or sympathomimetic drugs.


Phenobarbital (Primidone): Population pharmacokinetic analyses indicate that tiagabine clearance is 60% greater in patients taking phenobarbital (primidone) with or without other enzyme-inducing AEDs.


Cholestyramine increases enterohepatic elimination of amiodarone and may reduce its serum levels and t1/2.


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.


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.


(1968, 1970), the higher serum concentrations of penicillins and cephaloridine reached after administration of probenecid are due not only to slower renal elimination but also to an altered distribution in the body.


Cholestyramine: Cholestyramine binds both T4 and T3 in the intestine, thus impairing absorption of these thyroid hormones.


The serum concentration of phenytoin increased dramatically from 16.6 to 49.1 microg/mL when fluvoxamine was coadministered, although the daily dosage of phenytoin and other drugs had not changed.


On the basis of the metabolism of bexarotene by cytochrome P450 3A4, ketoconazole, itraconazole, erythromycin, gemfibrozil, grapefruit juice, and other inhibitors of cytochrome P450 3A4 would be expected to lead to an increase in plasma bexarotene concentrations.


Interaction between glycine and glutamate in the development of spontaneous motility in chick embryos.


Pharmacokinetic interaction studies with cetirizine in adults were conducted with pseudoephedrine, antipyrine, ketoconazole, erythromycin and azithromycin.


The extent to which SSRI-TCA interactions may pose clinical problems will depend on the degree of inhibition and the pharmacokinetics of the SSRI involved.


Ethosuximide: Amphetamines may delay intestinal absorption of ethosuximide.


In clinical studies performed with Fondaparinux, the concomitant use of oral anticoagulants (warfarin), platelet inhibitors (acetylsalicylic acid), NSAIDs (piroxicam), and digoxin did not significantly affect the pharmacokinetics/pharmacodynamics of fondaparinux sodium.


Caffeine-related adverse effects have occurred in patients consuming caffeine while on therapy with enoxacin.


Excessive neuromuscular weakness may be exacerbated by administration of another botulinum toxin prior to the resolution of the effects of a previously administered botulinum toxin.


PROSTIN E2 may augment the activity of other oxytocic drugs.


Therefore, the potential exists for a drug interaction between WELLBUTRIN and drugs that affect the CYP2B6 isoenzyme (e.g., orphenadrine and cyclophosphamide).


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.


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


NSAIDs: In in vitro studies, M1 was shown to cause increases ranging from 13 - 50% in the free fraction of diclofenac and ibuprofen at concentrations in the clinical range.


When Vardenafil dosing was separated from terazosin 10 mg by 6 hours, 7 of 28 subjects who received 20 mg of Vardenafil experienced a decrease in standing systolic blood pressure below 85 mm Hg.


Because prostaglandins play an important role in hemostasis, and NSAIDs affect platelet function as well, concurrent therapy with all NSAIDs, including diclofenac, and warfarin requires close monitoring of patients to be certain that no change in their anticoagulant dosage is required.


In a study in normal volunteers, it was found that chronic concurrent administration of 3.6 g of aspirin per day decreases indomethacin blood levels approximately 20%.


Nevertheless, caution is indicated in the coadministration of TCAs with any of the SSRIs and also in switching from one class to the other.


Quinidine, verapamil, amiodarone, propafenone, indomethacin, itraconazole, alprazolam, and spironolactone raise the serum digoxin concentration due to a reduction in clearance and/or in volume of distribution of the drug, with the implication that digitalis intoxication may result.


Reciprocal interactions may occur with concomitant use of Antizol and drugs that increase or inhibit the cytochrome P450 system (e.g., phenytoin, carbamazepine, cimetidine, ketoconazole), though this has not been studied


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


INDOCIN can reduce the antihypertensive effects of captopril and losartan.


Therefore, dose adjustments of concomitant medications that are predominantly metabolized by CYP2D6 and have a narrow therapeutic index (e.g., flecainide, vinblastine, thioridazine and most tricyclic antidepressants) may be required.


Antacids and sucralfate: Sucralfate and antacids containing magnesium or aluminum, as well as formulations containing divalent and trivalent cations such as Videx  (didanosine), chewable/buffered tablets or the pediatric powder for oral solution can form chelation complexes with lomefloxacin and interfere with its bioavailability.


Vitamin D3 administration to rachitic chicks was effective in significantly elevating duodenal arsenate absorption, acting primarily to enhance serosal transport.


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.


Particular caution should be exercised in using preparations containing sulfur, resorcinol, or salicylic acid in combination with DIFFERIN Gel.


The majority of patients in RA clinical studies received one or more of the following concomitant medications with ORENCIA: MTX, NSAIDs, corticosteroids, TNF blocking agents, azathioprine, chloroquine, gold, hydroxychloroquine, leflunomide, sulfasalazine, and anakinra.


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


Anticoagulants: Flurbiprofen like other nonsteroidal anti-inflammatory drugs, has been shown to affect bleeding parameters in patients receiving anti-coagulants, and serious clinical bleeding has been reported.


Nonsteroidal anti-inflammatory agents (NSAIDS): Concomitant use of aspirin (or other nonsteroidal antiinflammatory agents) and corticosteroids increases the risk of gastrointestinal side effects.


Terfenadine, astemizole and cisapride are all metabolized by the cytochrome P450IIIA4 isozyme, and it has been demonstrated that ketoconazole, a potent inhibitor of IIIA4, blocks the metabolism of these drugs, resulting in increased plasma concentrations of parent drug.


Limited clinical experience indicates that requirements for volatile inhalation anesthetics are reduced by 30 to 50% for the first sixty (60) minutes following ALFENTA induction The concomitant use of erythromycin with ALFENTA can significantly inhibit ALFENTA clearance and may increase the risk of prolonged or delayed respiratory depression.


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.


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.


ACE inhibitors: Reports suggest that NSAIDs may diminish the antihypertensive effect of Angiotensin Converting Enzyme (ACE) inhibitors.


Ibogaine attenuates, but 18-MC potentiates, the acute locomotor effects of morphine;


Cimetidine is reported to reduce hepatic metabolism of certain tricyclic antidepressants, thereby delaying elimination and increasing steady-state concentrations of these drugs.


The Cmax of norethindrone was 13% higher when it was coadministered with gabapentin;


In a Phase I trial using escalating doses of TAXOL (110-200 mg/m2) and cisplatin (50 or 75 mg/m2) given as sequential infusions, myelosuppression was more profound when TAXOL was given after cisplatin than with the alternate sequence (ie, TAXOL before cisplatin).


- Anabolic steroids (nandrolone [e.g., Anabolin], oxandrolone [e.g., Anavar], oxymetholone [e.g., Anadrol], stanozolol [e.g., Winstrol]) or


Aspirin: Animal studies wshow that aspirin given with nonsteroidal anti-inflammatory agents, including ibuprofen, yields a net decrease in anti-inflammatory activity with lowered blood levels of the non-aspirin drug.


Concurrent use of phenothiazines may antagonize the anorectic effect of diethylpropion.


If treatment with inhibitors of CYP3A4 activity (such as ketoconazole, intraconazole, ritonavir, indinavir, saquinavir, erythromycin, etc.) is indicated, reduction of the budesonide dose should be considered.


Noncardioselective beta-blockers (nadolol,porpranolol,timolol) may exacerbate rebound hypertension when guanfacine is withdrawn.


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).


however, no deleterious interactions were seen when ROMAZICON was administered after narcotics, inhalational anesthetics, muscle relaxants and muscle relaxant antagonists administered in conjunction with sedation or anesthesia.


- Perhexiline hydrogen maleate or MAO-inhibitors (with hepatotoxic potential) must not be administered together with Bezalip or Bezalip retard.


DOSTINEX should not be administered concurrently with D2-antagonists, such as phenothiazines, butyrophenones, thioxanthines, or metoclopramide.


The concomitant administration of bosentan and cyclosporine A is contraindicated.


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.


It is recommended that serum lithium levels be monitored frequently if PRINIVIL is administered concomitantly with lithium.


Epidural clonidine may prolong the duration of pharmacologic effects of epidural local anesthetics, including both sensory and motor blockade.


Alkalinizing agents: Gastrointestinal alkalinizing agents (sodium bicarbonate, etc.) increase absorption of amphetamines.


Coumarin Anticoagulants: There have been rare reports of increased prothrombin time in patients taking coumarin anticoagulants to whom nifedipine was administered.


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


In addition, drugs that are actively secreted via this route (e.g., triamterene, metformin and amiloride) should be co-administered with care as they might increase dofetilide levels.


Nevertheless, the effects of Mefloquine on travelers receiving comedication, particularly diabetics or patients using anticoagulants, should be checked before departure.


Erythromycin use in patients who are receiving high doses of theophylline may be associated with an increase in serum theophylline levels and potential theophylline toxicity.


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.


In vitro studies evaluating the minimum inhibitory concentration (MIC) of vancomycin, cefazolin, ampicillin, ampicillin/flucoxacillin, ceftazidime, gentamicin, and amphotericin demonstrated no evidence of incompatibility of these antibiotics with EXTRANEAL.


Clidinium may decrease the effect of phenothiazines, levodopa, and ketoconazole.


Clinical studies in healthy volunteers show that the pharmacokinetics of CANCIDAS are not altered by itraconazole, amphotericin B, mycophenolate, nelfinavir, or tacrolimus.


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.


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.


Urinary acidifying agents (ammonium chloride, sodium acid phosphate, etc.) increase the concentration of the ionized species of the amphetamine molecule, thereby increasing urinary excretion.


Phenobarbital: Amphetamines may delay intestinal absorption of phenobarbital;


- a sulfa-based drug such as sulfamethoxazole-trimethoprim (Bactrim, Septra), sulfisoxazole (Gantrisin), or sulfasalazine (Azulfidine);


Trecator may potentiate the adverse effects of other antituberculous drugs administered concomitantly.


Patients receiving other narcotic analgesics, antipsychotics, antianxiety agents, or other CNS depressants (including alcohol) concomitantly with hydrocodone and acetaminophen tablets may exhibit an additive CNS depression.


This increase is due to the inhibition of celecoxib metabolism via P450 2C9 by fluconazole (see CLINICAL PHARMACOLOGY - Pharmacokinetics: Metabolism).


[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.


Corticosteroids: Dexamethasone: Aprepitant, when given as a regimen of 125mg with dexamethasone coadministered orally as 20 mg on Day 1, and Aprepitant when given as 80 mg/day with dexamethasone coadministered orally as 8 mg on Days 2 through 5, increased the AUC of dexamethasone, a CYP3A4 substrate by 2.2-fold, on Days 1 and 5.


Drug Interactions with Antacids Administration of 120 mg of fexofenadine hydrochloride (2 x 60 mg capsule) within 15 minutes of an aluminum and magnesium containing antacid (Maalox ) decreased fexofenadine AUC by 41% and cmax by 43%.


Lithium: Increased serum lithium levels and symptoms of lithium toxicity have been reported in patients receiving concomitant lithium and ACE inhibitor therapy.


Therefore, patients receiving probenecid will have erroneously low ERPF and Tm PAH values.


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.


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.


Carbamazepine - Combined administration of racemic citalopram (40 mg/day for 14 days) and carbamazepine (titrated to 400 mg/day for 35 days) did not significantly affect the pharmacokinetics of carbamazepine, a CYP3A4 substrate.


This may occur because diflunisal competitively displaces coumarins from protein binding sites.


Aspirin: As with other NSAIDs, concomitant administration of Ponstel and aspirin is not generally recommended because of the potential of increased adverse effects.


These results suggest that acute dosing with clozapine would not affect behaviors most closely associated with PCP intoxication.


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


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.


Nonsteroidal Anti-inflammatory Drugs (NSAIDs): The concomitant administration of a nonsteroidal anti inflammatory drug with a quinolone may increase the risks of CNS stimulation and convulsions.


therefore, it is theoretically possible that lansoprazole may interfere with the absorption of drugs where gastric pH is an important determinant of bioavailability (e.g. ketoconazole, ampicillin esters, iron salts, digoxin).


Misonidazole has a complex effect on oral CCNU pharmacokinetics.


Hepatic Enzyme Inducers, Inhibitors and Substrates: Drugs which induce cytochrome P450 3A4 (CYP 3A4) enzyme activity (e.g., barbiturates, phenytoin, carbamazepine, rifampin) may enhance the metabolism of corticosteroids and require that the dosage of the corticosteroid be increased.


The use of dextromethorphan hydrobromide may result in additive CNS depressant effects when coadministered with alcohol, antihistamines, psychotropics or other drugs that produce CNS depression.


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.


Higher concentrations of dexamethasone (10(-8) - 10(-6) M) or retinyl acetate (3 X 10(-8) - 10(-7) M) enhance the mitogenic activity of EGF.


Agents with Increased Levels in the Presence of Carbamazepine: EQUETROTM increases the plasma levels of the following agents: Clomipramine HCl, Phenytoin(6), and primidone Thus, if a patient has been titrated to a stable dosage on one of the agents in this category, and then begins a course of the treatment with EQUETROTM, it is reasonable to expect that a dose decrease for the concomitant agent may be necessary.


ACE inhibitors: Reports suggest that NSAIDs may diminish the antihypertensive effect of Angiotensin Converting Enzyme (ACE) inhibitors.


Alcohol: Has a synergistic effect with aspirin in causing gastrointestinal bleeding.


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


Specific Effects of Felbatol  on Other Antiepileptic Drugs Phenytoin: Felbatol  causes an increase in steady-state phenytoin plasma concentrations.


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.


It is not known whether this potentiation of ampicillin rashes is due to allopurinol or the hyperuricemia present in these patients.


Aspirin: When Lodine is administered with aspirin, its protein binding is reduced, although the clearance of free etodolac is not altered.


Pre-treatment with the CYP3A4 inducer rifampicin decreased erlotinib AUC by about 2/3.


Phospholine Iodide potentiates other cholinesterase inhibitors such as succinylcholine or organophosphate and carbamate insecticides.


Multivitamins, or other products containing iron or zinc, antacids or sucralfate should not be administered concomitantly with, or within 2 hours of, the administration of norfloxacin, because they may interfere with absorption resulting in lower serum and urine levels of norfloxacin.


Therefore, EXTREME CAUTION should be exercised when administering dopamine HCl to patients receiving cyclopropane or halogenated hydrocarbon anesthetics.


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.


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.


Seizures have been reported in patients taking another quinolone class antimicrobial and the nonsteroidal anti-inflammatory drug fenbufen concurrently.


RESULTS: The geometric mean (90% confidence interval) whole blood sirolimus area under the plasma concentration time-curve increased 60% (35%-90%), from 736 to 1178 ng x h/mL, and maximum concentration increased 43% (14%-81%), from 67 to 96 ng/mL, with diltiazem coadministration, whereas the mean elimination half-life of sirolimus decreased slightly, from 79 to 67 hours.


Potential drug interactions between Keppra  and other AEDs (carbamazepine, gabapentin, lamotrigine, phenobarbital, phenytoin, primidone and valproate) were also assessed by evaluating the serum concentrations of levetiracetam and these AEDs during placebo-controlled clinical studies.


Orlistat-Orlistat may decrease the absorption of vitamin K.


- a diuretic (water pill) such as hydrochlorothiazide (HCTZ, Hydrodiuril), chlorothiazide (Diuril), and others;


Metoclopramide: Bioavailability is mildly reduced (approximately 10%) when zalcitabine and metoclopramide are coadministered.


A potential interaction between oral miconazole and oral hypoglycemic agents leading to severe hypoglycemia has been reported.


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.


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


Caution is therefore advised in the coadministration of ATROVENT Inhalation Aerosol with other anticholinergic-containing drugs.


May interact with the following: cholestyramine, colestipol (use with thiazide diuretics may prevent the diuretic from working properly;


Neuroleptic Drugs - L-phenylalanine may potentiate the tardive dyskinesia side reactions of neuroleptic drugs if used concomitantly with them.


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


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.


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;


Ascorbic acid: Doses of ascorbic acid (vitamin C) 1 g/day have been reported to increase plasma concentration of synthetic estrogens by ~47%, possibly by inhibiting conjugation;


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.


Beta-adrenergic blocking agents should be withdrawn at least 48 hours before conducting an arbutamine-mediated stress test.


Nevertheless, clinical studies, as well as postmarketing observations have shown that Lodine can reduce the natriuretic effect of furosemide and thiazides in some patients.


- 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);


Caution is advised when TRISENOX is coadministered with other medications that can prolong the QT interval (e.g. certain antiarrhythmics or thioridazine) or lead to electrolyte abnormalities (such as diuretics or amphotericin B).


Antihistamines may have additive effects with alcohol and other CNS depressants, e.g., hypnotics, sedatives, tranquilizers, antianxiety agents.


Diuretics: Studies in normal volunteers have shown that flurbiprofen like other nonsteroidal anti-inflammatory drugs, can interfere with the effects of furosemide.


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.


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


Consequently, it is recommended that fluvoxamine not be used in combination with either terbinafine, astemizole, or cisapride.


Aprepitant has been shown to induce the metabolism of S(-) warfarin and tolbutamide, which are metabolized through CYP2C9.


Caution should be used if naproxen is administered concomitantly with methotrexate.


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.


There have been inconsistent reports regarding the effects of other drugs (e.g., quinine, penicillamine) on serum digoxin concentration.


The successive application of glycine (5 or 10 mg/kg egg weight (e.w.) and glutamate (15 mg/kg e.w.) in a 10 min interval significantly increased the activation of spontaneous motility of 17-day-old chick embryos in comparison with the effect of glutamate alone.


Tetracycline, a bacteriostatic antibiotic, may antagonize the bactericidal effect of penicillin and concurrent use of these drugs should be avoided.


If desipramine hydrochloride is to be combined with other psychotropic agents such as tranquilizers or sedative/hypnotics, careful consideration should be given to the pharmacology of the agents employed since the sedative effects of desipramine and benzodiazepines (e.g., chlordiazepoxide or diazepam) are additive.


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).


Pyrazolone Derivatives (phenylbutazone, oxyphenbutazone, and possibly dipyrone): Concomitant administration with aspirin may increase the risk of gastrointestinal ulceration.


Also, due to the potential for additive effects such as bradycardia and AV block, caution is warranted in patients receiving clonidine with agents known to affect sinus node function or AV nodal conduction (e.g., digitalis, calcium channel blockers, and beta-blockers.)


Concomitant administration of erythromycin and digoxin has been reported to result in elevated digoxin serum levels.


Chlorthalidone may add to or potentiate the action of other antihypertensive drugs.


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.


Adenosine: Dipyridamole has been reported to increase the plasma levels and cardiovascular effects of adenosine.


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.


Antiacid, clarithromycin, Didanosine, Fluconazole, Fluoxetine, Indanavir, Ketoconazole, Phenytoin, Phenobarbitol, carbamazepine, Rifabutin, Rifampin, Ritanovir, Saquinavir.


Urinary acidifying agents (ammonium chloride, sodium acid phosphate, etc.) increase the concentration of the ionized species of the amphetamine molecule, thereby increasing urinary excretion.


Concomitant use of zalcitabine and lamivudine is not recommended.


Terfenadine, astemizole and cisapride are all metabolized by the cytochrome P450IIIA4 isozyme, and it has been demonstrated that ketoconazole, a potent inhibitor of IIIA4, blocks the metabolism of these drugs, resulting in increased plasma concentrations of parent drug.


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.


TCAs decrease the hypotensive effect of guanfacine.


therefore, it is theoretically possible that lansoprazole may interfere with the absorption of drugs where gastric pH is an important determinant of bioavailability (e.g. ketoconazole, ampicillin esters, iron salts, digoxin).


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.


Cyclophosphamide treatment, which causes a marked and persistent inhibition of cholinesterase activity, potentiates the effect of succinylcholine chloride.


Interaction of GABITRIL with Other Drugs : Cimetidine : Co-administration of cimetidine (800 mg/day) to patients taking tiagabine chronically had no effect on tiagabine pharmacokinetics.


Isoflurane, enflurane, and halothane decrease the ED50 of NUROMAX by 30% to 45%.


Elevated plasma levels of theophylline have been reported with concomitant quinolone use.


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


Aprepitant increased the AUC of midazolam by 25% on Day 4 and decreased the AUC of midazolam by 19% on Day 8 relative to the dosing of Aprepitant on Days 1 through 3.


The pressor effects of catecholamines such as dopamine or norepinephrine are enhanced by Bretylium Tosylate.


Lithium: Increased serum lithium levels and symptoms of lithium toxicity have been reported in patients receiving ACE inhibitors during therapy with lithium.


Moreover, as noted with alprazolam, the effect of fluvoxamine may even be more pronounced when it is administered at higher doses.


Ketamine: Marked hypertension and tachycardia have been reported in association with concomitant administration of levothyroxine sodium and ketamine.


Increased nephrotoxicity has been reported following concomitant administration of cephalosporins and aminoglycoside antibiotics.


Total body clearance of Simulect was reduced by an average 22% and 51% when azathioprine and mycophenolate mofetil, respectively, were added to a regimen consisting of cyclosporine, USP (MODIFIED) and corticosteroids.


Potassium Supplements and Potassium-Sparing Diuretics: Fosinopril sodium can attenuate potassium loss caused by thiazide diuretics.


The safety and efficacy of concomitant use of REVIA and disulfiram is unknown, and the concomitant use of two potentially hepatotoxic medications is not ordinarily recommended unless the probable benefits outweigh the known risks.


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.


therefore, it is theoretically possible that lansoprazole may interfere with the absorption of drugs where gastric pH is an important determinant of bioavailability (e.g. ketoconazole, ampicillin esters, iron salts, digoxin).


Concomitant use of calcium supplements and L-lysine may increase calcium absorption


Drugs that reduce the number of blood platelets by causing bone marrow depression (such as antineoplastic agents) or drugs which inhibit platelet function (eg, aspirin and other non-steroidal anti-inflammatory drugs, dipyridamole, hydrochloroquine, clofibrate, dextran) may increase the bleeding tendency produced by anticoagulants without altering prothrombin time determinations.


Amitriptyline: Concurrent administration of 25 mg or 100 mg cinacalcet with 50 mg amitriptyline increased amitriptyline exposure and nortriptyline (active metabolite) exposure by approximately 20% in CYP2D6 extensive metabolizers.


Corticosteroids: Concomitant administration with aspirin may increase the risk of gastrointestinal ulceration and may reduce serum salicylate levels.


Therefore, CYP3A4 substrates known to have a narrow therapeutic index such as alfentanil, astemizole, terfenadine, cisapride, cyclosporine, fentanyl, pimozide, quinidine, sirolimus, tacrolimus, or ergot alkaloids (ergotamine, dihydroergotamine) should be administered with caution in patients receiving SPRYCEL.


- When Bezalip or Bezalip retard is used concurrently with anion-exchange resins (e.g. cholestryramine), an interval of at least 2 hours should be maintained between the two medicines, since the absorption of Bezalip or Bezalip retard is impaired


THE POTENTIATING ACTION OF HYDROXYZINE MUST BE CONSIDERED WHEN THE DRUG IS USED IN CONJUNCTION WITH CENTRAL NERVOUS SYSTEM DEPRESSANTS SUCH AS NARCOTICS, NON-NARCOTIC ANALGESICS AND BARBITURATES.


The concomitant administration of rifampin and warfarin resulted in the need for an unusually high maintenance dose of warfarin (20 mg per day) in order to produce a therapeutic effect.


In rheumatoid arthritis, concomitant medications besides MTX were nonsteroidal anti-inflammatory agents, folic acid, corticosteroids and/or narcotics.


Phenytoin: Serum phenytoin levels may be increased by aspirin.


Morphine prolonged gastrointestinal transit time from 69 to 103 minutes (P = .005); this was prevented by ADL 8-2698 (P = .004).


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


Isoflurane or enflurane administered with nitrous oxide/oxygen to achieve 1.25 MAC [Minimum Alveolar Concentration] may prolong the clinically effective duration of action of initial and maintenance doses of NIMBEX and decrease the required infusion rate of NIMBEX.


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).


Several tricyclic antidepressants have been reported to block the pharmacologic effects of guanethidine, clonidine, or similar agents, and such an effect may be anticipated with CMI because of its structural similarity to other tricyclic antidepressants.


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.


Although there are no study data to evaluate the possibility, nitric oxide donor compounds, including sodium nitroprusside and nitroglycerin, may have an additive effect with INOmax on the risk of developing methemoglobinemia.


A similar association, though less marked, has been suggested with barbiturates, phenyl-butazone, phenytoin sodium, carbamazepine and possibly with griseofulvin, ampicillin, and tetracyclines (72)


Nevertheless, caution is indicated in the co-administration of TCAs with any of the SSRIs and also in switching from one class to the other.


Cimetidine: Cimetidine has been reported to produce clinically significant fluctuations in steady-state serum concentrations of various tricyclic antidepressants.


Inhibitors of this isoenzyme (e.g., macrolide antibiotics, azole antifungal agents, protease inhibitors, serotonin reuptake inhibitors, amiodarone, cannabinoids, diltiazem, grapefruit juice, nefazadone, norfloxacin, quinine, zafirlukast) should be cautiously coadministered with TIKOSYN as they can potentially increase dofetilide levels.


Hypotension: Patients on Diuretic Therapy: Patients on diuretics and especially those in whom diuretic therapy was recently instituted, may occasionally experience an excessive reduction of blood pressure after initiation of therapy with enalapril or enalaprilat.


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.


- Non-steroidal Anti-inflammatory Drugs: In some patients, the administration of a non-steroidal anti-inflammatory agent can reduce the diuretic, natriuretic, and antihypertensive effects of loop, potassium-sparing and thiazide diuretics.


Certain drugs, including nonsteroidal anti-inflammatory agents (NSAIDs), salicylates, monoamine oxidase inhibitors, and non-selective beta-adrenergic-blocking agents may potentiate the hypoglycemic action of Starlix and other oral antidiabetic drugs.


In a ten-subject study, coadministration of diltiazem (120 mg bid) with lovastatin resulted in a 3-4 times increase in mean lovastatin AUC and Cmax vs. lovastatin alone;


Lithium: Valdecoxib 40 mg BID for 7 days produced significant decreases in lithium serum clearance (25%) and renal clearance (30%) with a 34% higher serum exposure compared to lithium alone.