A study in eight healthy volunteers has shown a 50% increase in mean peak nimodipine plasma concentrations and a 90% increase in mean area under the curve, after a one week course of cimetidine at 1,000 mg/day and nimodipine at 90 mg/day.


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


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


Patients using CYP3A4 metabolized statins should have cholesterol levels monitored after TRACLEER is initiated to see whether the statin dose needs adjustment.


Rifampin: Coadministration of rifampin and MEPRON Suspension results in a significant decrease in average steady- state plasma atovaquone concentrations.


The concomitant use of transdermal fentanyl with ritonavir or other potent 3A4 inhibitors such as ketoconazole, itraconazole, troleandomycin, clarithromycin, nelfinavir, and nefazadone may result in an increase in fentanyl plasma concentrations.


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


Interactions between treatments with coumaphos, bishydroxycoumarin (an anticoagulant), trichlorfon (an organophosphorous compound), and phenobarbital sodium (an inducer of microsomal enzymes) were investigated in sheep.


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


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.


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.


Cimetidine increased the AUC of epirubicin by 50%.


Patients receiving high doses of salicylates concomitantly with furosemide, as in rheumatic disease, may experience salicylate toxicity at lower doses because of competitive renal excretory sites.


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


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.


Valproate: A recent case study has shown a possible increase in the plasma level of valproate when co administered with isoniazid.


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.


As with other antipsychotic agents, it should be noted that HALDOL may be capable of potentiating CNS depressants such as anesthetics, opiates, and alcohol.


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


Amitriptyline in combination with clonidine enhances the manifestation of corneal lesions in rats Epidural Injection Clonidine may potentiate the CNS-depressive effect of alcohol, barbiturates or other sedating drugs.


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


Accordingly, when diflunisal is administered with oral anticoagulants, the prothrombin time should be closely monitored during and for several days after concomitant drug administration.


Ergot derivatives: dihydroergotamine, ergonovine, ergotamine, methylergonovine


Doxylamine may enhance the effects of epinephrine.


Since caffeine is frequently co-administered with acetaminophen, it is of clinical interest to study the effect of caffeine on the hepatotoxicity of acetaminophen.


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.


Injection: Lorazepam injection, like other injectable benzodiazepines, produces depression of the central nervous system when administered with ethyl alcohol, phenothiazines, barbiturates, MAO inhibitors, and other antidepressants.When scopolamine is used concomitantly with injectable lorazepam, an increased incidence of sedation, hallucinations, and irrational behavior has been observed.


In Study 1, patients with colorectal cancer were given irinotecan/5-FU/leucovorin (bolus-IFL) with or without AVASTIN.


It is known that CYP1A2 is inhibited by several medicinal products, including fluvoxamine, and such medicinal products could theoretically adversely influence the clearance of anagrelide.


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.


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.


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.


Coadministration of terfenadine with Itraconazole has led to elevated plasma concentrations of terfenadine, resulting in rare instances of life- threatening cardiac dysrhythmias and one death.


There have been rare reports of significant respiratory depression, stupor and/or hypotension with the concomitant use of loxapine and lorazepam.


Warfarin: Quinolones have been reported to enhance the effects of the oral anticoagulant warfarin or its derivatives.


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


Auranofin should not be used together with penicillamine (Depen, Cuprimine), another arthritis medication.


If iron supplements are required during OMNICEF therapy, OMNICEF should be taken at least 2 hours before or after the supplement.


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.


There is no information regarding the effect on lamivudine pharmacokinetics of higher doses of TMP/SMX such as those used to treat Pneumocystis carinii pneumonia.


Caution should also be applied for other sympathomimetics, and for aminophylline and theophylline and tricyclic antidepressants, which may also precipitate arrhythmias.


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.


Lithium: NSAIDs have produced an elevation of plasma lithium levels and a reduction in renal lithium clearance.


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


Other quinolones have demonstrated moderate to marked interference with the metabolism of caffeine, resulting in a reduced clearance, a prolongation of plasma half-life, and an increase in symptoms that accompany high levels of caffeine.


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


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.


Drugs that inhibit cytochrome P450IID6, such as quinidine , might increase the plasma concentrations of flecainide in patients that are on chronic flecainide therapy;


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.


The effects of ERGOMAR may be potentiated by triacetyloleandomycin which inhibits the metabolism of ergotamine.


A similar association, though less marked, has been suggested with barbiturates, phenylbutazone, phenytoin sodium, carbamazepine, griseofulvin, topiramate, and possibly with ampicillin and tetracyclines 72.


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


Although neither dexamethasone nor retinyl acetate affected the proliferation of prostatic epithelium in RPMI1640 containing transferrin alone, they modify the mitogenic effect of EGF and insulin.


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.


Warfarin: Quinolones may enhance the effects of the oral anticoagulant, warfarin, or its derivatives.


Thus, probenecid should not be administered concurrently with bumetanide.


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.


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.


Drugs that reportedly may increase oral anticoagulant response, ie, increased prothrombin response, in man include:alcohol*;


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.


There is thus an enhancement effect of PGF2alpha upon the reaction of placental vessels to oxytocin in vitro.


Bismuth: Bismuth subsalicylate, given concomitantly with enoxacin or 60 minutes following enoxacin administration, decreased enoxacin bioavailability by approximately 25%.


Dose reduction of rifabutin to half the standard dose and a dose increase of CRIXIVAN to 1000 mg (three 333-mg capsules) every 8 hours are recommended when rifabutin and CRIXIVAN are coadministered.


Caution should be exercised if tacrolimus and bosentan are used together.


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


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


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.


Anabolic steroids (particularly C-17 alkylated androgens such as oxymetholone, methandrostenolone, norethandrolone, and similar compounds) enhanced tendency toward edema.


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


Monoamine oxidase (MAO) inhibitors such as isocarboxazid (e.g., Marplan), phenelzine (e.g., Nardil), procarbazine (e.g., Matulane), selegiline (e.g., Eldepryl), and tranylcypromine (e.g., Parnate): Using these medicines with L-tryptophan may increase the chance of side effects.


Drugs which may enhance the neuromuscular blocking action of TRACRIUM include: enflurane;isoflurane;halothane;certain antibiotics, especially the aminoglycosides and polymyxins;lithium;magnesium salts;procainamide;and quinidine.


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) .


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.


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


The uptake inhibitors cocaine and desipramine (3 mumol/liter) potentiated the positive inotropic effects of norepinephrine in nonfailing myocardium (p < 0.05) but not in functional class IV myocardium.


The concomitant use of ENABLEX with other anticholinergic agents may increase the frequency and/or severity of dry mouth, constipation, blurred vision and other anticholinergic pharmacological effects.


The concomitant use of transdermal fentanyl with ritonavir or other potent 3A4 inhibitors such as ketoconazole, itraconazole, troleandomycin, clarithromycin, nelfinavir, and nefazadone may result in an increase in fentanyl plasma concentrations.


When the STADOL NS was administered 30 minutes after the sumatriptan nasal spray, the AUC of butorphanol increased 11% and Cmax decreased 18%.


Atorvastatin: Atorvastatin increases the AUC for norethindrone and ethinyl estradiol.


Anesthetics/Sedatives/Hypnotics/Opioids: Co-administration of PRECEDEX with anesthetics, sedatives, hypnotics, and opioids is likely to lead to an enhancement of effects.


Acarbose may affect digoxin bioavailabillty and may require dose adjustment of digoxin by 16% (90% confidence interval: 8-23%), decrease mean C max digoxin by 26% (90% confidence interval: 16-34%) and decrease mean trough concentrations of digoxin by 9% (90% confidence limit: 19% decrease to 2% increase).


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


Concurrent administration of oxyphenbutazone and androgens may result in elevated serum levels of oxyphenbutazone.


Protease Inhibitors: In vitro data indicate that indinavir and ritonavir markedly inhibit the metabolism of cisapride which can result in an increase in plasma cisapride levels and prolongation of the QT interval on the ECG.


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


Azlocillin should not be administered concomitantly with amikacin, ciprofloxacin, gentamicin, netilmicin, or tobramycin.


The antimicrobial combinations of GL with four antibiotics resulted in additive effect in most instances, synergism in two instances, and antagonism in two instances.


Indinavir may be taken with a light meal 1 h following the administration of 400 mg of didanosine.


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


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.


Based on adult data, lower doses of caffeine may be needed following coadministration of drugs which are reported to decrease caffeine elimination (e.g., cimetidine and ketoconazole) and higher caffeine doses may be needed following coadministration of drugs that increase caffeine elimination (e.g., phenobarbital and phenytoin).


Uricosuric drugs, such as probenecid and sulfinpyrazone, can inhibit renal tubular secretion of nitrofurantoin.


include terfenadine, astemizole, cisapride, midazolam, and triazolam.


5HT3 Antagonists: Based on reports of profound hypotension and loss of consciousness when apomorphine was administered with ondansetron, the concomitant use of apomorphine with drugs of the 5HT3 antagonist class (including, for example, ondansetron, granisetron, dolasetron, palonosetron, and alosetron) is contraindicated .


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


Drug Interaction with Erythromycin and Ketoconazole Fexofenadine has been shown to exhibit minimal (ca. 5%) metabolism.


Valdecoxib caused a statistically significant increase in plasma exposures of R-warfarin and S-warfarin (12% and 15%, respectively), and in the pharmacodynamic effects (prothrombin time, measured as INR) of warfarin.


Drugs that induce hepatic enzymes such as phenobarbital, phenytoin and rifampin may increase the clearance of corticosteroids and may require increases in corticosteroid dose to achieve the desired response.


Careful observations on hepatotoxicity are suggested when acetaminophen is prescribed with caffeine.


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


Co-administration of TIKOSYN with verapamil resulted in increases in dofetilide peak plasma levels of 42%, although overall exposure to dofetilide was not significantly increased.


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.


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;


Concurrent administration of indinavir and didanosine significantly reduces the level of exposure to indinavir, but it is unclear how soon after didanosine administration indinavir may be given safely.


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


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.


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;


Neurochemical and functional consequences following 1-methyl-4-phenyl-1,2,5,6-tetrahydropyridine (MPTP) and methamphetamine.


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);


When amiloride HCl is administered concomitantly with an angiotensin-converting enzyme inhibitor, the risk of hyperkalemia may be increased.


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%.


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.


Experience with co-administration of HMG-CoA reductase inhibitors and Fentanyl in patients is limited,therefore,consideration should be given to temporarily suspending use of HMG-CoA reductase inhibitors in patients receiving Fentanyl.


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


Beta-blockers, clonidine, lithium salts, and alcohol may either potentiate or weaken the blood-glucose-lowering effect of insulin.


In diabetic patients, the metabolic effects of androgens may decrease blood glucose and therefore, insulin requirements.


Agents Causing Renin Release: The antihypertensive effect of enalapril and enalapril IV is augmented by antihypertensive agents that cause renin release (e.g., diuretics).


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


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.


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


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.


In these patients whose hypertension was controlled with nifedipine, Vardenafil 20 mg produced mean additional supine systolic/diastolic blood pressure reductions of 6/5 mm Hg compared to placebo.


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.


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


Iodine or iodine excess may decrease the effect of Carbimazole, and an iodine deficiency can increase the effect of Carbimazole.


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.


Phenothiazines and butyrophenones may reduce or reverse the pressor effect of epinephrine.


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


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.


Aminosalicylic acid may also decrease the absorption of vitamin B12, which can lead to a deficiency.


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.


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.


As with other agents with b-blocking properties, if COREG is to be administered orally with calcium channel blockers of the verapamil or diltiazem type, it is recommended that ECG and blood pressure be monitored.


Cardiac effects of dopamine are antagonized by beta-adrenergic blocking agents, such as propranolol and metoprolol.


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.


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


Although the clinical significance is not known, it is not recommended that cefditoren pivoxil be taken concomitantly with antacids.


Patients who begin taking diclofenac or who increase their diclofenac dose or any other NSAID while taking digoxin, methotrexate, or cyclosporine may develop toxicity characteristics for these drugs.


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.


MAO inhibitors prolong and intensify the anticholinergic (drying) effects of antihistamines.


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


- 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);


The following medications have been administered in clinical trials with Simulect with no increase in adverse reactions: ATG/ALG, azathioprine, corticosteroids, cyclosporine, mycophenolate mofetil, and muromonab-CD3.


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).


Products containing calcium and other multivalent cations (such as aluminum, magnesium, iron) are likely to interfere with absorption of Ibandronate.


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.


- Drugs that may decrease plasma phenytoin concentrations include: carbamazepine, chronic alcohol abuse, reserpine


Since the pharmacokinetics of BUSULFEX were studied in patients treated with phenytoin, the clearance of BUSULFEX at the recommended dose may be lower and exposure (AUC) higher in patients not treated with phenytoin.


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.


NSAIDs may decrease the hemodynamic effects of hydralazine;


Some quinolones, including ciprofloxacin, have also been shown to interfere with the metabolism of caffeine.


Oral anticoagulants may potentiate the hypoglycemic action of hypoglycemic agents, eg, tolbutamide and chlorpropamide, by inhibiting their metabolism in the liver.


Drug-Drug Interactions Given the primary CNS effects of aripiprazole, caution should be used when ABILIFY is taken in combination with other centrally acting drugs and alcohol.


Clinical trials have indicated that Pulmozyme can be effectively and safely used in conjunction with standard cystic fibrosis therapies including oral, inhaled and/or parenteral antibiotics, bronchodilators, enzyme supplements, vitamins, oral or inhaled corticosteroids, and analgesics.


Patients receiving flurbiprofen and furosemide or other diuretics should be observed closely to determine if the desired effect is obtained.


Beta-blockers, clonidine, lithium salts, and alcohol may either potentiate or weaken the blood-glucose-lowering effect of insulin.


Although the interactions observed in these studies do not appear to be of major clinical importance, BREVIBLOC should be titrated with caution in patients being treated concurrently with digoxin, morphine, succinylcholine or warfarin.


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.


Similarly, the effects of phenytoin on phenobarbital, valproic acid and sodium plasma valproate concentrations are unpredictable


Theophylline: Grepafloxacin is a competitive inhibitor of the metabolism of theophylline.


The absorption of lymecycline may be affected by the simultaneous administration of indigestion remedies, iron or zinc supplements.


These studies indicate that ketoconazole or erythromycin co-administration enhances fexofenadine gastrointestinal absorption.


Those for which effectiveness is reported includes diphenhydramine, hydroxyzine, orphenadrine, pyrilamine, phenyltoloxamine, promethazine, methdilazine, and tripelennamine.


Therefore, such combined treatment should be approached with caution and patients should be monitored closely when Clozapine is combined with these drugs, particularly with fluvoxamine.


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


Both the magnitude and duration of central nervous system and cardiovascular effects may be enhanced when ALFENTA is administered in combination with other CNS depressants such as barbiturates, tranquilizers, opioids, or inhalation general anesthetics.


In healthy subjects receiving cimetidine (1 gm daily) for one week, plasma flecainide levels increased by about 30% and half-life increased by about 10%.


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


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


In vitro studies indicate that ertapenem does not inhibit P-glycoprotein-mediated transport of digoxin or vinblastine and that ertapenem is not a substrate for P-glycoprotein-mediated transport.


It is recommended not to exceed a single 5 mg dose of Vardenafil in a 24-hour period when used in combination with erythromycin.


Since the pharmacokinetics of BUSULFEX were studied in patients treated with phenytoin, the clearance of BUSULFEX at the recommended dose may be lower and exposure (AUC) higher in patients not treated with phenytoin.


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


Rifampin and warfarin: a drug interaction.


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 concomitant intake of alcohol and Acamprosate does not affect the pharmacokinetics of either alcohol or acamprosate.


Pretreatment of healthy volunteers with multiple doses of rifampin followed by a single dose of Gleevec, increased Gleevec oral-dose clearance by 3.8-fold, which significantly (p 0.05) decreased mean cmax and AUC(0-8).


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.


Opioids are strong central nervous system depressants, but regular users develop physiological tolerance allowing gradually increased dosages.


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.


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


Although in vivo studies have not been done to see if etodolac clearance is changed by coadministration of phenylbutazone, it is not recommended that they be coadministered.


These agents include medications such as: anticoagulants, platelet inhibitors including acetylsalicylic acid, sali-cylates, NSAIDs (including ketorolac tromethamine), dipyridamole, or sulfinpyrazone.


Drugs that induce hepatic enzymes such as phenobarbital, phenytoin and rifampin may increase the clearance of corticosteroids and may require increases in corticosteroid dose to achieve the desired response.


In uninfected volunteers, 46% developed rash while receiving SUSTIVA and clarithromycin.


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.


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


In a study of schizophrenic patients who received clozapine under steady state conditions, fluvoxamine or paroxetine was added in 16 and 14 patients, respectively.


Acetaminophen, lidocaine, phenobarbital, quinidine, theophylline, and valproic acid were added to pooled human serum at therapeutic concentrations.


Some quinolones, including ciprofloxacin, have been associated with transient elevations in serum creatinine in patients receiving cyclosporine concomitantly.


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 chlorprothixene is given concomitantly with opioids, the opioid dose should be reduced (by approx. 50%), because chlorprothixene amplifies the therapeutic actions and side-effects of opioids massively.


Phenytoin: Amphetamines may delay intestinal absorption of phenytoin;


The plasma concentration of CMI has been reported to be increased by the concomitant administration of haloperidol;


Particular caution should be observed with digitalis preparations since there are conflicting results for the effect of colestipol hydrochloride on the availability of digoxin and digitoxin.


In addition to bleeding associated with heparin and vitamin K antagonists, drugs that alter platelet function (such as acetylsalicylic acid, dipyridamole and Abciximab) may increase the risk of bleeding if administered prior to, during, or after Activase therapy.


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.


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


Vardenafil dose should not exceed a maximum of 2.5 mg in a 24-hour period in patients receiving concomitant indinavir therapy.


Because of the pronounced intersubject variability in the extent of the sirolimus-diltiazem interaction, whole blood sirolimus concentrations should be monitored closely in patients treated with the two drugs.


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


Hypotension, AV conduction disturbances, and left ventricular failure have been reported in some patients receiving beta-adrenergic blocking agents when an oral calcium antagonist was added to the treatment regimen.


- 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);


Lithium: In a study conducted in healthy subjects, mean steady-state lithium plasma levels increased approximately 17% in subjects receiving lithium 450 mg BID with CELEBREX 200 mg BID as compared to subjects receiving lithium alone.


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.


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;


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


Drugs that induce hepatic enzymes such as phenobarbital, phenytoin and rifampin may increase the clearance of corticosteroids and may require increases in corticosteroid dose to achieve the desired response.


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


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.


In a study involving healthy subjects receiving TAMBOCOR and propranolol concurrently, plasma flecainide levels were increased about 20% and propranolol levels were increased about 30% compared to control values.


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.


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


Nevertheless, the prothrombin time or other suitable coagulation test should be monitored when warfarin or its derivatives and enoxacin are given concomitantly.


Paroxetine: Coadministration of a single dose of Sonata 20 mg and paroxetine 20 mg daily for 7 days did not produce any interaction on psychomotor performance.


Beta-blockers, clonidine, lithium salts, and alcohol may either potentiate or weaken the blood-glucose-lowering effect of insulin.


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


A two-way interaction between the hydantoin antiepileptic, phenytoin, and the coumarin anticoagulants has been suggested.


Protease Inhibitors: In vitro data indicate that indinavir and ritonavir markedly inhibit the metabolism of cisapride which can result in an increase in plasma cisapride levels and prolongation of the QT interval on the ECG.


- Probenecid: Pretreatment with probenecid reduces both the natriuresis and hyperreninemia produced by bumetanide.


Drug-Drug Interactions Albuterol - STRATTERA should be administered with caution to patients being treated with systemically-administered (oral or intravenous) albuterol (or other beta2 agonists) because the action of albuterol on the cardiovascular system can be potentiated resulting in increases in heart rate and blood pressure.


Toxicology studies of heroin-related deaths reveal frequent involvement of other central nervous system depressants, including alcohol, benzodiazepines such as diazepam (Valium), and, to a rising degree, methadone.


Because the tetracyclines have been shown to depress plasma prothrombin activity, patients who are on anticoagulant therapy may require downward adjustment of their anticoagulant dosage.


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


Theophylline: As with some other quinolones, concurrent administration of ciprofloxacin with theophylline may lead to elevated serum concentrations of theophylline and prolongation of its elimination half-life.


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


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).


Agents that induce CYP3A4 (eg, carbamazepine) could cause an increase in aripiprazole clearance and lower blood levels.


RESULTS: During treatment with fluvoxamine, there was a statistically significant decrease in the median of the total clearance of tolbutamide, from 845 mL/h to 688 mL/h, among the volunteers who received 75 mg/d.


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;


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.


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 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.


Coadministration of propoxyphene decreased the maximum plasma concentration of alprazolam by 6%, decreased clearance by 38%, and increased half-life by 58%.


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


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


Interaction of clindamycin and gentamicin in vitro.


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.


Garlic Capsules Garlic capsules should not be used while taking saquinavir (FORTOVASE) as the sole protease inhibitor due to the risk of decreased saquinavir plasma concentrations.


Serious anticholinergic symptoms (severe dry mouth, urinary retention, blurred vision) have been associated with elevations in the serum levels of tricyclic antidepressants when cimetidine is added to the drug regimen.


Binding to plasma protein is not significantly altered by diazepam, diphenylhydantoin, or phenylbutazone.


Experience with nonsteroidal anti-inflammatory drugs (NSAIDs) suggests the potential for interactions with furosemide and ACE inhibitors.


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.


Methotrexate: Ibuprofen, as well as other nonsteroidal anti-inflammatory drugs, probably reduces the tubular secretion of methotrexate based on in vitro studies in rabbit kidney slices.


Coadministration of astemizole with ketoconazole tablets is therefore contraindicated.


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.


Drug interaction studies have shown that esomeprazole does not have any clinically significant interactions with phenytoin, warfarin, quinidine, clarithromycin or amoxicillin.


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


Drugs that cause significant sustained elevation in gastric pH (histamine H2-receptor antagonists such as ranitidine or cimetidine) may reduce plasma concentrations of IRESSA and therefore potentially may reduce efficacy.


[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.


Prolonged recovery time may occur if barbiturates and/or narcotics are used concurrently with ketamine.


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.


In a multiple dose study of theophylline (400 mg once daily for 3 days) and cetirizine (20 mg once daily for 3 days), a 16% decrease in the clearance of cetirizine was observed.


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


In clinical trials, FLOLAN was used with digoxin, diuretics, anticoagulants, oral vasodilators, and supplemental oxygen.In a pharmacokinetic substudy in patients with congestive heart failure receiving furosemide or digoxin in whom therapy with FLOLAN was initiated, apparent oral clearance values for furosemide (n = 23) and digoxin (n = 30) were decreased by 13% and 15%, respectively, on the second day of therapy and had returned to baseline values by day 87.


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.


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.


The pharmacokinetics and protein binding of fosphenytoin, phenytoin, and diazepam were not altered when diazepam and Cerebyx were concurrently administered in single submaximal doses.


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


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


In vivo studies: Nitrates: The blood pressure lowering effects of sublingual nitrates (0.4 mg) taken 1 and 4 hours after vardenafil and increases in heart rate when taken at 1, 4 and 8 hours were potentiated by a 20 mg dose of Vardenafil in healthy middle-aged subjects.


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


- 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);


Other depressasnts such as alcohol, barbiturates, and MAOIs may enhance CNS depression when administered with ethchlorvynol.


When other antiplatelet agents or anticoagulants are used concomitantly, there is the potential for FLOLAN to increase the risk of bleeding.


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, a slower onset can be anticipated if STADOL NS is administered concomitantly with, or immediately following, a nasal vasoconstrictor.


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.


Chlorthalidone and related drugs may increase the responsiveness to tubocurarine.


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


Before using this medication, tell your doctor or pharmacist of all prescription and nonprescription products you may use, especially of: aminoglycosides (e.g., gentamicin, amikacin), amphotericin B, cyclosporine, non-steroidal anti-inflammatory drugs (e.g., ibuprofen), tacrolimus, vancomycin.


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


In ewes given 40 mg of phenobarbital sodium/kg for 5 days intraperitoneally (IP), the anticholinesterase effect of 4 mg of coumaphos/kg was significantly reduced and signs of toxicity were not present.


Clonidine hydrochloride may enhance the CNS-depressive effects of alcohol, barbiturates or other sedatives.


Endothelium-intact aortic rings from high-estradiol rats were supersensitive to noradrenaline when compared to vehicle-, progesterone- and progesterone + high-estradiol-treated rats (pD2 values = 7.77+/-0.12, 7.21+/-0.13, 6.93+/-0.04 and 7.22+/-0.18, respectively).


The elimination half life of midazolam and triazolam also increased (1.5-2.5 fold) during coadministration with diltiazem.


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;


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%.


Consider additive sedative effects and confusional states to emerge, if chlorprothixene is given with benzodiazepines or barbituates.


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


Patients who begin taking diclofenac or who increase their diclofenac dose or any other NSAID while taking digoxin, methotrexate, or cyclosporine may develop toxicity characteristics for these drugs.


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


Concurrent administration of low-dose dopamine HCl and diuretic agents may produce an additive or potentiating effect on urine flow.


5HT3 Antagonists: Based on reports of profound hypotension and loss of consciousness when apomorphine was administered with ondansetron, the concomitant use of apomorphine with drugs of the 5HT3 antagonist class (including, for example, ondansetron, granisetron, dolasetron, palonosetron, and alosetron) is contraindicated .


If iron supplements are required during OMNICEF therapy, OMNICEF should be taken at least 2 hours before or after the supplement.


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.


Valproate: The addition of tiagabine to patients taking valproate chronically had no effect on tiagabine pharmacokinetics, but valproate significantly decreased tiagabine binding in vitro from 96.3 to 94.8%, which resulted in an increase of approximately 40% in the free tiagabine concentration.


Interactions may occur with the following: adrenocorticoids (cortisone-like medicine), anticoagulants (blood thinners), carbamazepine, corticotropin (barbiturates may decrease the effects of these medicines), central nervous system (CNS) depressants (using these medicines with barbiturates may result in increased CNS depressant effects), divalproex sodium, valproic acid (using these medicines with barbiturates may change the amount of either medicine that you need to take), and oral contraceptives containing estrogens (barbiturates may decrease the effectiveness of these oral contraceptives, and you may need to change to a different type of birth control).


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.


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


However, halothane anesthetic requirement (i.e., MAC) was depressed in a dose-dependent fashion as much as 56% 1-2 hours and as much as 14% 5-6 hours after injection of ketamine, 50 mg/kg, im.


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


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;


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.


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.


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


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


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


If you are also using a steroid inhaler, take bitolterol first and then wait about 15 minutes before using the steroid inhaler.


Although the interactions observed in these studies do not appear to be of major clinical importance, BREVIBLOC should be titrated with caution in patients being treated concurrently with digoxin, morphine, succinylcholine or warfarin.


Amphotericin, Foscarnet, and Aminoglycosides: Drugs such as amphotericin, foscarnet, and aminoglycosides may increase the risk of developing peripheral neuropathy or other HIVID-associated adverse events by interfering with the renal clearance of zalcitabine (thereby raising systemic exposure).


Sildenafil dose should not exceed a maximum of 25 mg in a 48- hour period in patients receiving concomitant indinavir therapy.


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


- a 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);


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.


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.


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.


Edema has been reported in patients concomitantly receiving Itraconazole and dihydropyridine calcium channel blockers.


Antacids increase the rate of absorption of pseudoephedrine, while kaolin decreases it.


The absorption of tetracycline, furosemide, penicillin G, hydrochlorothiazide, and gemfibrozil was significantly decreased when given simultaneously with colestipol hydrochloride;


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.


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.


- Drugs that may either increase or decrease plasma phenytoin concentrations include: phenobarbital, vaiproic acid, and sodium valproate.


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


Injection: Lorazepam injection, like other injectable benzodiazepines, produces depression of the central nervous system when administered with ethyl alcohol, phenothiazines, barbiturates, MAO inhibitors, and other antidepressants.When scopolamine is used concomitantly with injectable lorazepam, an increased incidence of sedation, hallucinations, and irrational behavior has been observed.


Vasoconstrictors: D.H.E. 45  (dihydroergotamine mesylate) Injection, USP should not be used with peripheral vasoconstrictors because the combination may cause synergistic elevation of blood pressure.


Therefore, patients under methotrexate therapy should be carefully monitored when concomitant ciprofloxacin therapy is indicated.


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.


However, because some quinolones have been reported to enhance the effects of warfarin or its derivatives, prothrombin time or other suitable anticoagulation test should be monitored closely if a quinolone antimicrobial is administered with warfarin or its derivatives.


Antihistamines may partially counteract the anticoagulation effects of heparin or warfarin.


Quinolones, including cinoxacin, may enhance the effects of oral anticoagulants, such as warfarin or its derivatives.


Injection of estradiol 5 min before a nonlethal dose of endotoxin changed the serum sex steroid hormone response of male rats to endotoxin.


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.


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.


Inhibitors or substrates of CYP2D6 (i.e., quinidine, selective serotonin reuptake inhibitors [SSRIs]) may increase the plasma concentration of doxepin when administered concomitantly.


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.


No depressant effect on blood levels in humans was noted when colestipol hydrochloride was administered with any of the following drugs: aspirin, clindamycin, clofibrate, methyldopa, nicotinic acid (niacin), tolbutamide, phenytoin or warfarin.


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


Cholestyramine: Cholestyramine may increase the clearance of corticosteroids.


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.


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.


Steady-state bosentan plasma concentrations were 3- to 4-fold higher than in the absence of cyclosporine A.


Because of the small effect on half-life, the coadministration with probenecid to extend the half-life of ertapenem is not recommended.


Substances that are potent inhibitors of CYP3A4 activity (eg, ketoconazole and itraconazole) decrease gefitinib metabolism and increase gefitinib plasma concentrations.


Although glucocorticoids have been shown to reduce PROLEUKIN-induced side effects including fever, renal insufficiency, hyperbilirubinemia, confusion, and dyspnea, concomitant administration of these agents with PROLEUKIN may reduce the antitumor effectiveness of PROLEUKIN and thus should be avoided. 12 Beta-blockers and other antihypertensives may potentiate the hypotension seen with PROLEUKIN.


Possible drug interactions of HUMORSOL with succinylcholine or with other anticholinesterase agents.


In eight HIV-infected patients, the steady-state AUC of ciprofloxacin was decreased an average of 26% (95% CI = 14%, 37%) when ciprofloxacin was administered 2 hours prior to a marketed chewable/dispersible tablet formulation of VIDEX.


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


Accordingly, diazepam and fluvoxamine should not ordinarily be co-administered.


Cholestyramine-Concomitant intake of cholestyramine and vitamin K may reduce the absorption of vitamin K.


Administration of quinolones with antacids containing aluminum, magnesium, or calcium, with sucralfate, with metal cations such as iron, or with multivitamins containing iron or zinc, or with formulations containing divalent and trivalent cations such as VIDEX (didanosine) chewable/buffered tablets or the pediatric powder for oral solution, may substantially interfere with the absorption of quinolones, resulting in systemic concentrations considerably lower than desired.


Drug Interaction During Pregnancy: Cromolyn sodium and isoproterenol were studied following subcutaneous injections in pregnant mice.


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.


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.


Digoxin: In controlled studies in healthy volunteers, bepridil hydrochloride either had no effect (one study) or was associated with modest increases, about 30% (two studies) in steady-state serum digoxin concentrations.


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


Particular caution should be observed with digitalis preparations since there are conflicting results for the effect of colestipol hydrochloride on the availability of digoxin and digitoxin.


Chlorthalidone and related drugs may decrease arterial responsiveness to norepinephrine.


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


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.


Dexamethasone at 10(-10) M or retinyl acetate at about 3 X 10(-9) M inhibits proliferation stimulated by EGF.


The potential for drug interactions with EMTRIVA has been studied in combination with indinavir, stavudine, famciclovir, and tenofovir disoproxil fumarate.


Avoid the use of preparations such as decongestants and local anesthetics which contain any sympathomimetic amine (e.g., epinephrine, norepinephrine), since it has been reported that tricyclic antidepressants can potentiate the effects of catecholamines.


The effect of TORADOL on plasma lithium has not been studied, but cases of increased lithium plasma levels during TORADOL therapy have been reported.


The co-administration of Natrecor with IV vasodilators such as nitroglycerin, nitroprusside, milrinone, or IV ACE inhibitors has not been evaluated (these drugs were not co-administered with Natrecor in clinical trials).


Iodine or iodine excess may decrease the effect of Carbimazole, and an iodine deficiency can increase the effect of Carbimazole.


Probenecid: Concomitant administration of TORADOL ORAL and probenecid resulted in decreased clearance of ketorolac and significant increases in ketorolac plasma levels (total AUC increased approximately threefold from 5.4 to 17.8 m g/h/mL) and terminal half-life increased approximately twofold from 6.6 to 15.1 hours.


In patients with mild to moderate hypertension, administration of 25 mg daily of VIOXX with the ACE inhibitor benazepril, 10 to 40 mg for 4 weeks, was associated with an average increase in mean arterial pressure of about 3 mm Hg compared to ACE inhibitor alone.


Misonidazole protects mouse tumour and normal tissues from the toxicity of oral CCNU.


Corticosteroids, Methylxanthines and Diuretics: Concomitant treatment with xanthine derivatives, steroids, or diuretics may potentiate a possible hypokalemic effect of  beta2-agonists.


Animal experience indicates that clorazepate dipotassium prolongs the sleeping time after hexobarbital or after ethyl alcohol, increases the inhibitory effects of chlorpromazine, but does not exhibit monoamine oxidase inhibition.


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 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.


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.


Conversely, the administration of STADOL NS (1 mg butorphanol QID) did not alter the pharmacokinetics of a 300-mg dose of cimetidine.


Aspirin: Concomitant administration of low-dose aspirin with VIOXX may result in an increased rate of GI ulceration or other complications, compared to use of VIOXX alone.


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.


Cimetidine reduces the clearance of ALFENTA.


Adrenergic blockers Adrenergic blockers are inhibited by amphetamines.


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


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


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


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


When initiating a multi-day course of grepafloxacin in a patient maintained on theophylline, the theophylline maintenance dose should be halved for the period of concurrent use of grepafloxacin and monitoring of serum theophylline concentrations should be initiated as a guide to further dosage adjustments.


Since acetaminophen in high doses has been associated with hepatotoxicity, concomitant administration of diflunisal and acetaminophen should be used cautiously, with careful monitoring of patients.


Amitriptyline in combination with clonidine enhances the manifestation of corneal lesions in rats Epidural Injection Clonidine may potentiate the CNS-depressive effect of alcohol, barbiturates or other sedating drugs.


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.


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


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.


Cimetidine: In the presence of cimetidine at 300 mg QID (N=12) the mean apparent oral clearance of gabapentin fell by 14% and creatinine clearance fell by 10%.


Additive CNS depression may occur when antihistamines are administered concomitantly with other CNS depressants including barbiturates, tranquilizers, and alcohol.