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


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.


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.


Specific drug interaction studies have not been performed with SUSTIVA and NRTIs other than lamivudine and zidovudine.


Ritonavir: Coadministration of ritonavir with VIRACEPT resulted in a 152% increase in nelfinavir plasma AUC and very little change in ritonavir plasma A.C.


In a single study, rats given high intraperitoneal doses of an MAO inhibitor plus disulfiram experienced severe toxicity, including convulsions and death.


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


in one man, the C max of terfenadine was 8.1 ng/mL with terfenadine alone and 7.2 ng/mL with terfenadine plus dirithromycin.


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.


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.


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


In EM individuals treated with paroxetine or fluoxetine, the AUC of atomoxetine is approximately 6- to 8-fold and Css,max is about 3- to 4-fold greater than atomoxetine alone.


However, there are limited in vivo data suggesting a modest CYP2D6 inhibitory effect for escitalopram, i.e., coadministration of escitalopram (20 mg/day for 21 days) with the tricyclic antidepressant desipramine (single dose of 50 mg), a substrate for CYP2D6, resulted in a 40% increase in Cmax and a 100% increase in AUC of desipramine.


Flucytosine: while a synergistic relationship with amphotericin B has been reported, concomitant use may increase the toxicity of flucytosine by possibly increasing its cellular uptake and/or impairing its renal excretion.


In vitro mixing of an aminoglycoside with beta-lactamtype antibiotics (penicillins or cephalosporins) may result in a significant mutual inactivation.


Drugs Decreasing Heparin Effect: Digitalis, tetracyclines, nicotine, or antihistamines may partially counteract the anticoagulant action of heparin sodium.


DISCUSSION: Clarithromycin is a potent inhibitor of CYP3A4, the major enzyme responsible for simvastatin metabolism.


The absorption of oral gemifloxacin is significantly reduced by the concomitant administration of an antacid containing aluminum and magnesium.


Warfarin: In a short-term controlled study in 14 normal volunteers, ketoprofen did not significantly interfere with the effect of warfarin on prothrombin time.


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.


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.


It may be necessary to adjust the dosage of oral anticoagulants upon beginning or stopping disulfiram. since disulfiram may prolong prothrombin time.


Fentanyl Anesthesia: Severe hypotension has been reported during fentanyl anesthesia with concomitant use of a beta blocker and a calcium channel blocker.


Butyrophenones (such as haloperidol) and phenothiazines can suppress the dopaminergic renal and mesenteric vasodilation induced with low dose dopamine infusion.


On the contrary, neurotensin and tuftsin were agonists in induction of analgesia.


Rifampin may decrease serum digoxin concentration, especially in patients with renal dysfunction, by increasing the non-renal clearance of digoxin.


It is recommended that buspirone hydrochloride not be used concomitantly with MAO inhibitors Because the effects of concomitant administration of buspirone HCl with most other psychotropic drugs have not been studied, the concomitant use of buspirone HCl with other CNS-active drugs should be approached with caution.


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


Recovery of hoof twitch from 50% to 75% took 7.7 +/- 0.7 min for atracurium alone and 11.5 +/- 2.7 min for atracurium plus gentamycin (P = 0.03).


If phenytoin or other hepatic enzyme inducers are taken concurrently with Norpace or Norpace CR, lower plasma levels of disopyramide may occur.


Tolbutamide: Aprepitant, when given as 125 mg on Day 1 and 80 mg/day on Days 2 and 3, decreased the AUC of tolbutamide (a CYP2C9 substrate) by 23% on Day 4, 28% on Day 8, and 15% on Day 15, when a single dose of tolbutamide 500 mg was admini,stered orally prior to the administration of the 3-day regimen of Aprepitant and on Days 4,8, and 15.


Rifampin: Coadministration of rifampin and VIRACEPT resulted in an 82% decrease in nelfinavir plasma A.C.


Sildenafil is contraindicated in patients using long-acting nitrates or who may need to use short-acting nitrates, because the combination may cause a sharp fall of the blood pressure.


Antiretroviral Agents: No drug interactions with other antiretroviral medications have been identified that would warrant alteration of either the enfuvirtide dose or the dose of the other antiretroviral medication.


Because of its primary CNS effect, caution should be used when EQUETROTM is taken with other centrally acting drugs and alcohol.


Non-steroidal Anti-inflammatory Agents: In some patients with compromised renal function who are being treated with nonsteroidal anti-inflammatory drugs, the co-administration of enalapril may result in a further deterioration of renal function.


Presumably, phenytoin acts as a stimulator of coumarin metabolism and has been reported to cause decreased serum levels of the coumarin anticoagulants and increased prothrombin-proconvertin concentrations.


In a study of 15 male subjects (ages 19 to 35 years) who were extensive metabolizers of the CYP2D6 isoenzyme, daily doses of bupropion given as 150 mg twice daily followed by a single dose of 50 mg desipramine increased the Cmax, AUC, and t1/2 of desipramine by an average of approximately 2-, 5- and 2-fold, respectively.


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


Although these results do not indicate a significant interaction between TORADOL and warfarin or heparin, the administration of TORADOL to patients taking anticoagulants should be done extremely cautiously, and patients should be closely monitored.


The pressor effects of ERGOMAR and other vasoconstrictor drugs can combine to cause dangerous hypertension.


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


In combination with other central nervous system depressants, heroin may still kill even experienced users, particularly if their tolerance to the drug has reduced or the strength of their usual dose has increased.


The risk of using bromocriptine mesylate in combination with other drugs has not been systematically evaluated, but alcohol may potentiate the side effects of bromocriptine mesylate.


Patients with major psychotic disorders, treated with neuroleptics, should be treated with dopamine agonists only if the potential benefits outweigh the risks.


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.


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.


CANCIDAS reduced the blood AUC0-12 of tacrolimus by approximately 20%, peak blood concentration (Cmax) by 16%, and 12-hour blood concentration (C12hr) by 26% in healthy subjects when tacrolimus (2 doses of 0.1 mg/kg 12 hours apart) was administered on the 10th day of CANCIDAS 70 mg daily, as compared to results from a control period in which tacrolimus was administered alone.


poor metabolizers of debrisoquin: Interactions of carvedilol with strong inhibitors of CYP2D6 (such as quinidine, fluoxetine, paroxetine, and propafenone) have not been studied, but these drugs would be expected to increase blood levels of the R(+) enantiomer of carvedilol .


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


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.


Furosemide: Clinical studies, as well as post-marketing observations, have shown that NSAIDs can reduce the natriuretic effect of furosemide and thiazides in some patients.


Core temperature was decreased in rats in a dose-dependent manner when ethanol was administered to rats treated with disulfiram 8 hours before the ethanol challenge.


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


Aspirin: CELEBREX can be used with low dose aspirin.


Isoflurane potentiates the muscle relaxant effect of all muscle relaxants, most notably nondepolarizing muscle relaxants, and MAC (minimum alveolar concentration) is reduced by concomitant administration of N 2O.


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


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


In view of the potential risk of dehydration secondary to vomiting and/or diarrhea induced by CAMPTOSAR, the physician may wish to withhold diuretics during dosing with CAMPTOSAR and, certainly, during periods of active vomiting or diarrhea.


Erythromycin (500 mg t.i.d) produced a 4-fold increase in vardenafil AUC and a 3-fold increase in Cmax when co-administered with Vardenafil 5 mg in healthy volunteers.


The administration of guanfacine concomitantly with known microsomal enzyme inducer (phenobarbital or phenytoin) to two patients with renal impairment reportedly resulted in significant reductions in elimination half-life and plasma concentration.


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


Similarly, nateglinide had no influence on the serum protein binding of propranolol, glyburide, nicardipine, warfarin, phenytoin, acetylsalicylic acid, and tolbutamide in vitro .


Zalcitabine also has no significant effect on the intracellular phosphorylation of ZDV, as shown in vitro in peripheral blood mononuclear cells or in two other cell lines (U937 and Molt-4).


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


Other Cardiovascular Agents: Enalapril and enalapril IV have been used concomitantly with beta adrenergic-blocking agents, methyldopa, nitrates, calcium-blocking agents, hydralazine, prazosin and digoxin without evidence of clinically significant adverse interactions.


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


Resins: Since bile acid sequestrants may bind other drugs given concurrently, patients should take TRICOR at least 1 hour before or 4-6 hours after a bile acid binding resin to avoid impeding its absorption.


Interactions may also occur with the following: anti-depressants/anti-anxiety drugs, drugs used to treat an overactive thyroid, beta-blockers (e.g., propranolol), sparfloxacin, grepafloxacin, guanethidine, guanadrel, metrizamide, cabergoline, lithium, narcotic pain medication (e.g., codeine), drugs used to aid sleep, drowsiness-causing antihistamines (e.g., diphenhydramine), any other drugs that may make you drowsy.


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


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).


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.


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


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


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


Azithromycin had no significant impact on the Cmax and AUC of zidovudine, although it significantly decreased the zidovudine tmax by 44% and increased the intracellular exposure to phosphorylated zidovudine by 110%.


Administration of epinephrine to patients receiving cyclopropane or halogenated hydrocarbon general anesthetics such as halothane which sensitize the myocardium, may induce cardiac arrhythmia..


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


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


No significant interactions with digoxin, hydrochlorothiazide, hydralazine, sulfinpyrazone, oral contraceptives, tolbutamide, or warfarin have been observed.


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.


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


After the coadministration of 200 mg oral ketoconazole twice daily and one 20 mg dose of loratadine to 11 subjects, the AUC and Cmax of loratadine averaged 302% (  142 S.D.) and 251% (  68 S.D.), respectively, of those obtained after co-treatment with placebo.


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


Other strong inhibitors of CYP3A4 (e.g., itraconazole, clarithromycin, nefazodone, troleandomycin, ritonavir, nelfinavir) would be expected to behave similarly.


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


Phenytoin/Phenobarbital: The coadministration of phenytoin or phenobarbital will not affect plasma concentrations of vitamin D, but may reduce endogenous plasma levels of calcitriol/ergocalcitriol by accelerating metabolism.


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


At least 14 days should elapse between discontinuation of a MAO inhibitor and initiation of treatment with dexfenfluramine.


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


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


Cyclosporine: Because cyclosporine can produce nephrotoxicity with decreases in creatinine clearance and rises in serum creatinine, and because renal excretion is the primary elimination route of fibrate drugs including TRICOR, there is a risk that an interaction will lead to deterioration.


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


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.


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


Barbiturates and glutethimide should not be administered to patients receiving coumarin drugs.


Because oral anticoagulants may interfere with the hepatic metabolism of phenytoin, toxic levels of the anticonvulsant may occur when an oral anticoagulant and phenytoin are administered concurrently.


Use of PRINIVIL with potassium-sparing diuretics (e.g., spironolactone, triamterene, or amiloride), potassium supplements, or potassium-containing salt substitutes may lead to significant increases in serum potassium.


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


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


Analgesic/anti-inflammatory (e.g., acetaminophen, aspirin, codeine and codeine combinations, ibuprofen, indomethacin).


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


FLUOTHANE augments the action of non-depolarising muscle relaxants and the muscle relaxant effects of aminoglycosides.


Diflunisal decreased the hyperuricemic effect of furosemide.


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.


Phenylbutazone: Phenylbutazone causes increase (by about 80%) in the free fraction of etodolac.


Catecholamine-depleting drugs (e.g., reserpine) may have an additive effect when given with beta-blocking agents.


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.


- Drugs with ototoxic potential: Especially in the presence of impaired renal function, the use of parenterally administered bumetanide in patients to whom aminoglycoside antibiotics are also being given should be avoided, except in life-threatening conditions.


May interact with thyroid medication (e.g., levothyroxine), iodine-containing products, antacids, H2-antagonists (e.g., famotidine, ranitidine), and proton pump inhibitors (e.g., lansoprazole, omeprazole).


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


The effects of DCG-IV were very strong and completely depressed the PCP-induced hyperlocomotion.


Nevirapine and rifampin should not beadministered concomitantly becausedecreases in nevirapine plasmaconcentrations may reduce the efficacy ofthe drug.


Terfenadine: No clinically significant changes occurred in heart rate or corrected QT intervals, or in terfenadine metabolite or lomefloxacin pharmacokinetics, during concurrent administration of lomefloxacin and terfenadine at steady-state in 28 healthy males.


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.


Antacids or sucralfate substantially interfere with the absorption of some quinolones, resulting in low urine levels.


Calcium Antagonists: After repeated co-administration of Trileptal, the AUC of felodipine was lowered by 28% [90% CI: 20-33].


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.


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.


Clinically significant effects have been reported with the tricyclic antidepressants when used concomitantly with cimetidine.


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


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


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.


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.


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


A dose increase of lopinavir/ritonavir to 533/133 mg twice daily with food isrecommended in combination with nevirapine.


This interaction should be given consideration in patients taking BEXTRA concomitantly with ACE-inhibitors.


Drug-Drug Interactions: No clinically significant drug interactions have been found with theophylline at a low dose, azithromycin, pseudoephedrine, ketoconazole, or erythromycin.


Naproxen and other NSAIDs can reduce the antihypertensive effect of propranolol and other beta-blockers.


HIV Protease Inhibitors: Indinavir (800 mg t.i.d.) co-administered with Vardenafil 10 mg resulted in a 16-fold increase in vardenafil AUC, a 7-fold increase in vardenafil Cmax and a 2-fold increase in vardenafil half-life.


Interactions with Mixed Agonist/Antagonist Opioid Analgesics: Agonist/antagonist analgesics (eg, pentazocine, nalbuphine, butorphanol, dezocine and buprenorphine) should NOT be administered to a patient who has received or is receiving a course of therapy with a pure agonist opioid analgesic such as Levo-Dromoran.


Cimetidine: In a study in healthy volunteers, a one-week course of cimetidine at 400 mg b.i.d. with a single 5 mg dose of isradipine on the sixth day showed an increase in isradipine mean peak plasma concentrations (36%) and significant increase in area under the curve (50%).


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.


Rifampin, an inducer of drug metabolism, decreased the concentrations of losartan and its active metabolite.


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.


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.


Cyclopropane or halogenated hydrocarbon anesthetics increase cardiac autonomic irritability and may sensitize the myocardium to the action of certain intravenously administered catecholamines, such as dopamine.


These pharmacokinetic effects seen during diltiazem coadministration can result in increased clinical effects (e.g., prolonged sodation)of both midazolam and triazolam.


There are reports of enhanced as well as diminished effects of anticoagulants when given concurrently with corticosteroids.


The peripheral vasoconstriction caused by high doses of dopamine HCl is antagonized by alpha-adrenergic blocking agents.


Corticotropin may accentuate the electrolyte loss associated with diuretic therapy.


Haloperidol reduced or eliminated the increases in FI responding produced by intermediate doses of either (+)-NANM or PCP in pigeons, but did not antagonize the decreases in FI or FR responding produced by high doses of PCP or either stereoisomer of NANM.


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


Warfarin: Co-administration of bosentan 500 mg b.i.d. for 6 days decreased the plasma concentrations of both S-warfarin (a CYP2C9 substrate) and R-warfarin (a CYP3A4 substrate) by 29 and 38%, respectively.


Clinical implications of warfarin interactions with five sedatives.


Coadministration of SULAR with phenytoin or any known CYP3A4 inducer should be avoided and alternative antihypertensive therapy should be considered.


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.


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.


Nephrotoxicity has been reported following concomitant administration of aminoglycoside antibiotics and cephalosporin antibiotics.


However, due to possible pharmacodynamic interactions, when co-administered with PRECEDEX, a reduction in dosage of PRECEDEX on the concomitant anesthetic, sedative, hypnotic or opioid may be required.


The vasodilating effects of isosorbide mononitrate may be additive with those of other vasodilators.


Although no specific drug interactions with topical glaucoma drugs or systemic medications were identified in clinical studies of IOPIDINE 0.5% Ophthalmic Solution, the possibility of an additive or potentiating effect with CNS depressants (alcohol, barbiturates, opiates, sedatives, anesthetics) should be considered.


AIM AND BACKGROUND: The pharmacokinetic interaction between sirolimus, a macrolide immunosuppressant metabolized by CYP3A4, and the calcium channel blocker diltiazem was studied in 18 healthy subjects.


No significant drug-drug pharmacokinetic (or pharmacodynamic) interactions have been found in interaction studies with hydrochlorothiazide, digoxin, warfarin, and nifedipine.


Nonsteroidal Anti-Inflammatory Drugs: The administration of diflunisal to normal volunteers receiving indomethacin decreased the renal clearance and significantly increased the plasma levels of indomethacin.


Although no interaction between MAO inhibitors and Levo-Dromoran has been observed, it is not recommended for use with MAO inhibitors.


In some patients, the administration of INDOCIN can reduce the diuretic, natriuretic, and antihypertensive effects of loop, potassium-sparing, and thiazide diuretics.


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


Ritonavir: Coadministration of ritonavir with VIRACEPT resulted in a 152% increase in nelfinavir plasma AUC and very little change in ritonavir plasma A.C.


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


Nicardipine HCl usually does not alter the plasma levels of digoxin, however, serum digoxin levels should be evaluated after concomitant therapy with nicardipine HCl is initiated.


Because both of these drugs have negative inotropic properties and the effects of coadministration with TAMBOCOR are unknown, neither disopyramide nor verapamil should be administered concurrently with TAMBOCOR unless, in the judgment of the physician, the benefits of this combination outweigh the risks.


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.


These antibiotics should be used in the myasthenic patient only where definitely indicated, and then careful adjustment should be made of adjunctive anticholinesterase dosage.


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.


If these agents are to be administered concurrently, cyclosporine concentrations should be monitored, especially when diltiazem therapy is initiated, adjusted, or discontinued.


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


Concomitant administration of fenofibrate (equivalent to 145 mg TRICOR) with atorvastatin (20 mg) once daily for 10 days resulted in approximately 17% decrease (range from 67% decrease to 44% increase) in atorvastatin AUC values in 22 healthy males.


Although there is little published information on concomitant administration of lidocaine and Bretylium Tosylate, these drugs are often administered concurrently without any evidence of interactions resulting in adverse effects or diminished efficacy.


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


We conclude that the prophylactic and antidotal properties of 4-methylpyrazole seen in animals treated with 1,3-difluoro-2-propanol derive from its capacity to inhibit the NAD+-dependent oxidation responsible for converting 1,3-difluoro-2-propanol to 1,3-difluoroacetone in the committed step of the toxic pathway.


Interactions may also occur with the following: anti-depressants/anti-anxiety drugs, drugs used to treat an overactive thyroid, beta-blockers (e.g., propranolol), sparfloxacin, grepafloxacin, guanethidine, guanadrel, metrizamide, cabergoline, lithium, narcotic pain medication (e.g., codeine), drugs used to aid sleep, drowsiness-causing antihistamines (e.g., diphenhydramine), any other drugs that may make you drowsy.


Steady-state serum concentrations of tricyclic antidepressants are reported to fluctuate significantly when cimetidine is either added or deleted from the drug regimen.


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


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


For example, since cholestyramine may reduce the gastrointestinal absorption of both the oral anticoagulants and vitamin K, the net effects are unpredictable.


Tagamet, apparently through an effect on certain microsomal enzyme systems, has been reported to reduce the hepatic metabolism of warfarin-type anticoagulants, phenytoin, propranolol, nifedipine, chlordiazepoxide, diazepam, certain tricyclic antidepressants, lidocaine, theophylline and metronidazole, thereby delaying elimination and increasing blood levels of these drugs.


Furosemide: Clinical studies, as well as post marketing observations, have shown that NSAIDs can reduce the natriuretic effect of furosemide and thiazides in some patients.


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


Co-administration: Concomitant use of Argatroban with antiplatelet agents, thrombolytics, and other anticoagulants may 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.


Azithromycin had no significant impact on the Cmax and AUC of zidovudine, although it significantly decreased the zidovudine tmax by 44% and increased the intracellular exposure to phosphorylated zidovudine by 110%.


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 coadministration of aspirin decreases the biologic half-life of fenoprofen because of an increase in metabolic clearance that results in a greater amount of hydroxylated fenoprofen in the urine.


In a study in which patients with active RA were treated for up to 24 weeks with concurrent ENBREL  and anakinra therapy, a 7% rate of serious infections was observed, which was higher than that observed with ENBREL  alone (0%).


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


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


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


Although acid-base and electrolyte disturbances were not reported in the clinical trials with dorzolamide, these disturbances have been reported with oral carbonic anhydrase inhibitors and have, in some instances, resulted in drug interactions (e.g., toxicity associated with high-dose salicylate therapy).


The mode of toxic action of the pesticide gliftor: the metabolism of 1,3-difluoroacetone to (-)-erythro-fluorocitrate.


However, other published reports describe modest elevations (less than two-fold) of clozapine and metabolite concentrations when clozapine was taken with paroxetine, fluoxetine, and sertraline.


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;


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.


Propantheline and diphenoxylate, by decreasing gut motility, may increase digoxin absorption.


The effects of ketamine and of Innovar anesthesia on digitalis tolerance in dogs.


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


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 .


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


Co-administration of ketoconazole, a strong inhibitor of CYP3A4, increased cinacalcet exposure following a single 90 mg dose of Sensipar by 2.3 fold.


To study the pancreatic effects of other agents, dynamic insulin and glucagon release was measured from the in vitro perfused pancreases of normal and diabetic Chinese hamsters in response to various combinations of arginine (20mM), glucose (100 or 150 mg. per 100 ml.), and theophylline (10 mM).


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


Rifabutin: Coadministration of rifabutin and VIRACEPT resulted in a 32% decrease in nelfinavir plasma AUC and a 207% increase in rifabutin plasma A.C.


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


Metoclopramide: When coadministered with MONUROL, metoclopramide, a drug which increases gastrointestinal motility, lowers the serum concentration and urinary excretion of fosfomycin.


In separate studies of patients receiving maintenance doses of warfarin, hydrochlorothiazide, or digoxin, irbesartan administration for 7 days had no effect on the pharmacodynamics of warfarin (prothrombin time) or pharmacokinetics of digoxin.


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


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


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 plasma concentration of imipramine may increase when the drug is given concomitantly with hepatic enzyme inhibitors (e.g., cimetidine, fluoxetine) and decrease by concomitant administration of hepatic enzyme inducers (e.g., barbiturates, phenytoin), and adjustment of the dosage of imipramine may therefore be necessary.


Nifedipine: Vardenafil 20 mg, when co-administered with slow-release nifedipine 30 mg or 60 mg once daily, did not affect the relative bioavailability (AUC) or maximum concentration (Cmax) of nifedipine, a drug that is metabolized via CYP3A4.


Milk, milk products, and calcium-rich foods or drugs may impair the absorption of EMCYT.


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


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


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


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.


Because there is a theoretical basis that these effects may be additive, use of ergotamine-containing or ergot-type medications (like dihydroergotamine or methysergide) and AXERT within 24 hours of each other should be avoided.


Warfarin: When fluvoxamine maleate (50 mg tid) was administered concomitantly with warfarin for two weeks, warfarin plasma concentrations increased by 98% and prothrombin times were prolonged.


Digoxin: Coadministration of digoxin, a P-glycoprotein substrate, with oral conivaptan resulted in a reduction in clearance and an increase in digoxin Cmax and AUC values.


Similarly, nateglinide had no influence on the serum protein binding of propranolol, glyburide, nicardipine, warfarin, phenytoin, acetylsalicylic acid, and tolbutamide in vitro .


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


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;


This time window is different than for other oral formulations of ciprofloxacin, which are usually administered 2 hours before or 6 hours after antacids.


Other CNS depressant drugs should be used with caution in patients taking fenfluramine, since the effects may be additive.


Antacids: Enteric Coated Aspirin should not be given concurrently with antacids, since an increase in the pH of the stomach may effect the enteric coating of the tablets.


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


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


Cimetidine: Albendazole sulfoxide concentrations in bile and cystic fluid were increased (about 2-fold) in hydatid cyst patients treated with cimetidine (10 mg/kg/day) (n=7) compared with albendazole (20 mg/kg/day) alone (n=12).


Meperidine: Amphetamines potentiate the analgesic effect of meperidine.


Lithium: generally should not be given with diuretics.


Resistance to the neuromuscular blocking action of nondepolarizing neuromuscular blocking agents has been demonstrated in patients chronically administered phenytoin or carbamazepine.


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.


The following agents may increase certain actions or side effects of anticholinergic drugs. amantadine antiarrhythmic agents of class (e.g. quinidine), antihistamines antipsychotic agents (e.g. phenothiazines), benzodiazepines.


Diazepam: The co-administration of Fluvoxamine Tablets and diazepam is generally not advisable.


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


Although increased plasma concentrations (AUC 0-24 hrs) of loratadine and/or descarboethoxyloratadine were observed following coadministration of loratadine with each of these drugs in normal volunteers (n = 24 in each study), there were no clinically relevant changes in the safety profile of loratadine, as assessed by electrocardiographic parameters, clinical laboratory tests, vital signs, and adverse events.


Both 18-MC and ibogaine are sequestered in fat and, like ibogaine, 18-MC probably has an active metabolite.


Although it has not been definitively demonstrated that fluvoxamine is a potent IIIA4 inhibitor, it is likely to be, given the substantial interaction of fluvoxamine with alprazolam.


Plasma concentrations of quinolone antibiotics are decreased when administered with antacids containing magnesium, calcium, or aluminum.


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.


HEMABATE may augment the activity of other oxytocic agents.


Cholestyramine resin may delay or reduce the absorption of concomitant oral medication such as phenylbutazone, warfarin, thiazide diuretics (acidic) or propranolol (basic), as well as tetracycline penicillin G, phenobarbital, thyroid and thyroxine preparations, estrogens and progestins, and digitalis.


Concomitant treatment with methylxanthines (aminophylline, theophylline), steroids, or diuretics may potentiate any hypokalemic effect of adrenergic agonists.


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


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


Patients taking disopyramide phosphate and erythromycin concomitantly may develop increased serum concentrations of disopyramide resulting in excessive widening of the QRS complex and/or prolongation of the Q-T interval.


When amiodarone is added to flecainide therapy, plasma flecainide levels may increase two-fold or more in some patients, if flecainide dosage is not reduced.


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


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);


The zidovudine study dosed subjects with 1200 mg/day of azithromycin (n = 7) (later changed to 600 mg/day [n = 5]) for Days 8 to 21 of a 21-day course of 100 mg, five times/day of zidovudine.


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.


Combinations of clindamycin and gentamicin were indifferent for 16 and synergistic for 11 of the resistant strains.


Co-medications that induce CYP 3A4 (e.g., rifampicin, phenytoin, carbamazepine, phenobarbital, or St. John s wort) may significantly decrease exposure to exemestane.


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.


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


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


There have been reports of increased anticoagulant effects when erythromycin and oral anticoagulants were used concomitantly.


Digoxin and verapamil use may be rarely associated with ventricular fibrillation when combined with Adenocard.


Vitamin A and oral retinoids: Concomitant administration of vitamin A and/or other oral retinoids with acitretin must be avoided because of the risk of hypervitaminosis A.


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.


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


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.


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

phenothiazines classes of antipsychotic agents


Cevimeline should be administered with caution to patients taking beta adrenergic antagonists, because of the possibility of conduction disturbances.


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.


Antacids or H 2 receptor antagonists: When dirithromycin is administered immediately following antacids or H 2 -receptor antagonists, the absorption of dirithromycin is slightly enhanced.


Cardiac glycosides could exaggerate the depression of AV nodal conduction observed with bepridil hydrochloride.


Tagamet, apparently through an effect on certain microsomal enzyme systems, has been reported to reduce the hepatic metabolism of warfarin-type anticoagulants, phenytoin, propranolol, nifedipine, chlordiazepoxide, diazepam, certain tricyclic antidepressants, lidocaine, theophylline and metronidazole, thereby delaying elimination and increasing blood levels of these drugs.


There was a small increase in plasma concentrations of capecitabine and one metabolite (5-DFCR);


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.


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


- a 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);


Tricyclic antidepressants may enhance the seizure risk in patients taking tramadol


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.


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.


Discontinuation of cimetidine in well-controlled patients receiving tricyclic antidepressants and cimetidine may decrease the plasma levels and efficacy of the antidepressants.


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


This interaction should be given consideration in patients taking NSAIDs concomitantly with ACE inhibitors.


Although verapamil administered at either dose had little or no effect on the enhancement of intestinal carcinogenesis by bombesin or on the location, histologic type, depth of involvement, labeling index, apoptotic index or tumor vascularity of intestinal cancers, it significantly decreased the incidence of cancer metastasis.


Drugs which inhibit CYP 3A4 (e.g., ketoconazole, macrolide antibiotics such as erythromycin) have the potential to result in increased plasma concentrations of corticosteroids.


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


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


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


Increasing the indinavir dose to 1000 mg every 8 hours does not compensate for the increased indinavir metabolism due to efavirenz.


the doses of naloxone required to antagonize the effects of (-)-NANM were more than 100 times higher than those required to antagonize the effects of morphine.


Flurbiprofen pretreatment attenuated the hypotensive effect of a single dose of propranolol but not atenolol.


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


These results suggest that the analgesic effect of STADOL NS may be diminished when it is administered shortly after sumatriptan nasal spray, but by 30 minutes any such reduction in effect should be minimal.


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


Patients receiving concomitant lovastatin and erythromycin should be carefully monitored;


Curariform muscle relaxants (eg, tubocurarine) and other drugs, including ether, succinylcholine, gallamine, decamethonium and sodium citrate, potentiate the neuromuscular blocking effect and should be used with extreme caution in patients being treated with Coly-Mycin M Parenteral.


Anticholinergic drugs may antagonize the effects of the drugs that alter gastrointestinal motility, such as metoclopramide.


Although clinical studies have not been performed, based on the involvement of the cytochrome P-450 3A family in clonazepam metabolism, inhibitors of this enzyme system, notably oral antifungal agents, should be used cautiously in patients receiving clonazepam.


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


H-2 Antagonists: In studies with human volunteers, co-administration of cimetidine or ranitidine with ibuprofen had no substantive effect on ibuprofen serum concentrations.


Inhibitors Of Endogenous Prostaglandin Synthesis It has been reported that indomethacin may reduce the antihypertensive effect of captopril, especially in cases of low renin hypertension.


Methotrexate: Concomitant administration of methotrexate and some NSAIDs has been reported to reduce the clearance of methotrexate, enhancing the toxicity of methotrexate.


When carbamazepine is added to aripiprazole therapy, aripiprazole dose should be doubled.


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


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.


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.


Agents Increasing Serum Potassium: Enalapril and enalapril IV attenuate potassium loss caused by thiazide-type diuretics.


Phenytoin: If acitretin is given concurrently with phenytoin, the protein binding of phenytoin may be reduced.


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


Nifedipine did not alter the plasma levels of Vardenafil when taken in combination.


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


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.


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


The anticoagulant effect of heparin is enhanced by concurrent treatment with antithrombin III (human) in patients with hereditary antithrombin III deficiency.


Valproic acid diminished binding of phenobarbital by a net change of 9.9% (percentage increase in FDF, 21.2%) at 1732 micromol/L.


If labetalol HCl is used with nitroglycerin in patients with angina pectoris, additional antihypertensive effects may occur.


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


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


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


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


Response to sympathomimetic agents may be enhanced by colchicine.


Antibiotics: In vitro and/or in vivo data show that clarithromycin, erythromycin, and troleandomycin 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.


Because changes in glucose concentrations with valdecoxib coadministration were within the normal variability and individual glucose concentrations were above or near 70 mg/dL, dose adjustment for glyburide (5 mg QD and 10 mg BID) with valdecoxib coadministration (up to 40 mg QD) is not indicated.


Cimetidine treatment should be stopped during treatment with ELLENCE.


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.


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.


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


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


The plasma concentration of imipramine may increase when the drug is given concomitantly with hepatic enzyme inhibitors (e.g., cimetidine, fluoxetine) and decrease by concomitant administration of hepatic enzyme inducers (e.g., barbiturates, phenytoin), and adjustment of the dosage of imipramine may therefore be necessary.


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


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


Probenecid: Probenecid interferes with renal tubular secretion of ciprofloxacin and produces an increase in the level of ciprofloxacin in serum.


Phenytoin/Phenobarbital: The coadministration of phenytoin or phenobarbital will not affect plasma concentrations of vitamin D, but may reduce endogenous plasma levels of calcitriol/ergocalcitriol by accelerating metabolism.


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


poor metabolizers of debrisoquin: Interactions of carvedilol with strong inhibitors of CYP2D6 (such as quinidine, fluoxetine, paroxetine, and propafenone) have not been studied, but these drugs would be expected to increase blood levels of the R(+) enantiomer of carvedilol .


Caffeine: Enoxacin is a potent inhibitor of the cytochrome P-450 isozymes responsible for the metabolism of methylxanthines.


Alcohol: In post-marketing experience, there have been rare reports of adverse neuropsychiatric events or reduced alcohol tolerance in patients who were drinking alcohol during treatment with WELLBUTRIN.


therefore, plasma concentrations of phenytoin should also be monitored when it is given concurrently with Itraconazole.


In addition, neuromuscular blocking action is enhanced by general anesthetics, local anesthetics like lidocaine, procaine, beta-blockers, metaclopramide, lithium carbonate, and terbutaline.


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.


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: 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 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.


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.


Lincomycin has been shown to have neuromuscular blocking properties that may enhance the action of other neuromuscular blocking agents.


Aspirin: In normal volunteers, a small decrease in diflunisal levels was observed when multiple doses of diflunisal and aspirin were administered concomitantly.


Although deferasirox has a lower affinity for aluminum than for iron, Exjade should not be taken with aluminum-containing antacid preparations.


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.


and Videx , (Didanosine), chewable/buffered tablets or the pediatric powder for oral solution may substantially interfere with the absorption of quinolones, resulting in systemic levels considerably lower than desired.


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


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.


In general, most patients treated with dirithromycin who are receiving concomitant theophylline therapy may not require empiric adjustment of theophylline dosage or monitoring of theophylline plasma concentrations.


Studies have shown that lansoprazole does not have clinically significant interactions with other drugs metabolized by the cytochrome P450 system, such as warfarin, antipyrine, indomethacin, ibuprofen, phenytoin, propranolol, prednisone, diazepam, clarithromycin, or terfenadine in healthy subjects.


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


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.


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


Ketamine is clinically compatible with the commonly used general and local anesthetic agents when an adequate respiratory exchange is maintained.


We report the case of an adolescent with altered consciousness caused by carbamazepine overdose with a positive tricyclic antidepressant level to alert clinicians to the cross-reactivity of carbamazepine with a toxicology screen for tricyclic antidepressants.


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.


Acetazolamide reduces urinary excretion of quinidine and may enhance its effect.


Acetaminophen: A report of severe acetaminophen toxicity was reported in a patient receiving Isoniazid.


Monitoring for amiodarone toxicity and serial measurement of amiodarone serum concentration during concomitant protease inhibitor therapy should be considered.


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


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


- a 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);


Interactions with Mixed Agonist/Antagonist Opioid Analgesics: Agonist/antagonist analgesics (eg, pentazocine, nalbuphine, butorphanol, dezocine and buprenorphine) should NOT be administered to a patient who has received or is receiving a course of therapy with a pure agonist opioid analgesic such as Levo-Dromoran.


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


Mineral oil interferes with the absorption of fat-soluble vitamins, including vitamin D preparations.


Digitalis: Immediate Release Capsules: Since there have been isolated reports of patients with elevated digoxin levels, and there is a possible interaction between digoxin and nifedipine, it is recommended that digoxin levels be monitored when initiating, adjusting, and discontinuing nifedipine to avoid possible over- or under-digitalization.


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.


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


However, iloprost has the potential to increase the hypotensive effect of vasodilators and antihypertensive agents.


Do not mix TORADOL and morphine in the same syringe.


Nabilone has been shown to have an additive CNS depressant effect when given with either diazepam, secobarbitone sodium, alcohol or codeine.


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


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).


Initial doses of adrenergic agents, such as dopamine or epinephrine, should be reduced and titrated to achieve the desired response.


Because Anafranil is highly bound to serum protein, the administration of Anafranil to patients taking other drugs that are highly bound to protein (e.g., warfarin, digoxin) may cause an increase in plasma concentrations of these drugs, potentially resulting in adverse effects.


Methadone: Coadministration of amprenavir and methadone can decrease plasma levels of methadone.


Renal clearance measurements of PAH cannot be made with any significant accuracy in patients receiving sulfonamides, procaine, or thiazolesulfone.


In many of these cases, buprenorphine was misused by self-injection of crushed SUBUTEX tablets.


Stavudine and Zidovudine Ribavirin can antagonize the in vitro antiviral activity of stavudine and zidovudine against HIV.


Concomitant oral administration of ketoconazole (a known inhibitor of CYP3A4 activity in the liver and in the intestinal mucosa) caused an eight-fold increase of the systemic exposure to oral budesonide.


Aminosalicylic acid may decrease the amount of digoxin (Lanoxin, Lanoxicaps) that gets absorbed into your body.


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


However, in the second study, administration of 12 g cholestyramine 1 hour before the evening meal and 0.3 mg cerivastatin sodium approximately 4 hours after the same evening meal resulted in a decrease in the cerivastatin AUC of less than 8%, and a decrease in Cmax of about 30% when compared to dosing cerivastatin sodium alone.


When Bezalip or Bezalip retard is used at the same time as other medicines or substances the following interactions must be taken into account: - Bezalip and Bezalip retard may enhance the action of anticoagulants of the coumarin type.


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.


Ritonavir (600 mg b.i.d.) co-administered with Vardenafil 5 mg resulted in a 49-fold increase in vardenafil AUC and a 13-fold increase in vardenafil Cmax.


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


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 the, combination of anakinra with other TNF-blocking agents, including HUMIRA, may also result i n similar toxicities.


Phenytoin/Phenobarbital: The coadministration of phenytoin or phenobarbital will not affect plasma concentrations of vitamin D, but may reduce endogenous plasma levels of calcitriol/ergocalcitriol by accelerating metabolism.


Use of PRINIVIL with potassium-sparing diuretics (e.g., spironolactone, triamterene, or amiloride), potassium supplements, or potassium-containing salt substitutes may lead to significant increases in serum potassium.


Although the interaction between almotriptan and other potent CYP3A4 inhibitors (e.g., itraconazole, ritonavir, and erythromycin) has not been studied, increased exposures to almotriptan may be expected when almotriptan is used concomitantly with these medications.


There are rare reports, however, from marketing experiences, of changes in effects of insulin or oral hypoglycemic agents in the presence of diclofenac that necessitated changes in the doses of such agents.