Rifampin with warfarin

Clinically important, potentially hazardous interactions with albendazole, aminoglutethimide, aspirin, bexarotene, carbamazepine, cyclophosphamide, dasatinib, diuretics, ephedrine, imatinib, itraconazole, lapatinib, live vaccines, lopinavir, methotrexate, phenobarbital, phenytoin, praziquantel, primidone, rifampicin, rifampin, temsirolimus, warfarin... 

The anticoagulant effects of warfarin are markedly reduced by ri-fampicin (rifampin), with two to fivefold increases in dose needed to maintain efficacy in a number of case reports. Acenocoumarol and phenprocoumon are similarly affected. 

Phenytoin interacts widi many different drugp. For example isoniazid, chloramphenicol, sulfonamides, benzodiazepines, succinimides, and cimetidine all increase phenytoin blood levels. The barbiturates, rifampin, theophylline, and warfarin decrease phenytoin blood levels. When administering the hydantoins with meperidine, die analgesic effect of meperidine is decreased. 

Vitamin K is a fat-soluble vitamin cofactor for the activation of factors II, VII, IX, and X in the liver. Almost all neonates are vitamin K-deficient at as a result of (1) insignificant transplacental vitamin K crossover, (2) lack of colonization of the colon by vitamin K-producing bacteria, and (3) inadequate dietary vitamin K intake (especially in breast-fed infants because human milk contains less vitamin K than infant formula or cow s milk). Vitamin K-deficiency bleeding (VKDB) refers to bleeding attributable to vitamin K deficiency within first 6 months of life. It occurs in three general time frames early (0-24 hours), classic (1-7 days), and late (2-12 weeks). Early onset occurs rarely and usually is associated with maternal ingestion of anticonvulsants, rifampin, isoniazid, and warfarin. Classic vitamin K-dependent bleeding usually results from the lack of prophylactic vitamin K administration in... 

Oral azoles are associated with significant interactions, particularly due to cytochrome P-450 isoenzymes. Medications that interact with azoles include warfarin, phenytoin, theophylline, rifampin, cyclosporine, and zidovudine. For patients receiving only a few doses, these interactions do not pose a significant risk. These interactions may pose a risk for patients receiving long-term suppressive therapy for recurrent infections. 

Warfarin antagonists include vitamin K, barbiturates, glutethimide. rifampin, and cholestyramine. Warfarin potentiators include phenylbutazone. oxyphenbutazone, anabolic steroids, clofibrate, aspirin, hepatotoxins, disnlfirain, and metronidazole. In patients undergoing anticoagulation therapy with warfann, it has been found that cimetidine (used in therapy of duodenal ulcer) may increase anticoagulant blood levels and consequently prolong the prothrombin time. 

Decreased levels with enzyme inducers (rifampin). Increased levels wHh VPA. increased sedation with other CNS depressants. Decreased effectiveness of warfarin, CBZ, metronidazole, oral contraceptives. 

LM is a 65-year-old woman with AF, a seizure disorder, and latent tuberculosis infection. LM s medications include digoxin, rifampin, calcium carbonate, phenytoin, and warfarin. Which of the following drugs can interfere with the oral absorption of T4 ... 

Clinically important, potentially hazardous interactions with abarelix, acenocoumarol, amisulpride, amprenavir, anisindione, anticoagulants, arsenic, astemizole, carbimazole, celiprolol, ciprofloxacin, dabigatran, degarelix, dicumarol, digoxin, diltiazem, enoxacin, fentanyl, fosamprenavir, gatifloxacin, grapefruit juice, lomefloxacin, methotrexate, moxifloxacin, nilotinib, norfloxacin, ofloxacin, oxprenolol, quinidine, quinolones, rifabutin, rifampin, rifapentine, ritonavir, simvastatin, sparfloxacin, sulpiride, tacrolimus, tipranavir, verapamil, warfarin, zuclopenthixol... 

Clinically important, potentially hazardous interactions with alprazolam, astemizole, carbamazepine, cisapride, clarithromycin, dexamethasone, diltiazem, docetaxel, ifosfamide, imatinib, irinotecan, itraconazole, ketoconazole, methylprednisolone, midazolam, nefazodone, oral contraceptives, paroxetine, phenytoin, pimozide, rifampin, ritonavir, terfenadine, tolbutamide, trabectedin, troleandomycin, vinblastine, vincristine, warfarin... 

Clinically important, potentially hazardous interactions with diuretics, estrogens, ketoconazole, live vaccines, oral contraceptives, phenytoin, rifampin, warfarin... 

Clinically important, potentially hazardous interactions with amiloride, aminoglycosides, amphotericin B, ampicillin, anisindione, anticoagulants, armodafinil, atorvastatin, azathioprine, azithromycin, bacampicillin, basiliximab, bezafibrate, bosentan, bupropion, carbenicillin, caspofungin, cholestyramine, clarithromycin, cloxacillin, co-trimoxazole, corticosteroids, cyclophosphamide, daclizumab, danazol, dicloxacillin, dicumarol, digoxin, diltiazem, disulfiram, echinacea, erythromycin, ethotoin, etoposide, ezetimibe, flunisolide, fluoxymesterone, fluvastatin, foscarnet, fosphenytoin, gemfibrozil, hemophilus B vaccine, HMG-CoA reductase inhibitors, imatinib, imipenem/cilastatin, influenza vaccines, ketoconazole, lanreotide, lopinavir, lovastatin, mephenytoin, methicillin, methoxsalen, methylphenidate, methylprednisolone, methyltestosterone, mezlocillin, mizolastine, mycophenolate, nafcillin, nisoldipine, NSAIDs, orlistat, oxacillin, penicillins, phellodendron, phenytoin, pravastatin, prednisolone, prednisone, pristinamycin, ranolazine, red rice yeast, rifabutin, rifampin, rifapentine, ritonavir, rosuvastatin, simvastatin, sirolimus, spironolactone, St John s wort, sulfacetamide, sulfadiazine, sulfamethoxazole, sulfisoxazole, sulfonamides, tacrolimus, telithromycin, tenoxicam, testosterone, ticarcillin, tolvaptan, trabectedin, triamterene, troleandomycin, ursodeoxycholic acid, vaccines, vecuronium, warfarin, zofenopril... 

Clinically important, potentially hazardous interactions with adefovir, alprazolam, amprenavir, anisindione, anticoagulants, buprenorphine, carbamazepine, dicumarol, dihydroergotamine, ergot, fosamprenavir, indinavir, ixabepilone, lovastatin, methadone, methysergide, midazolam, phenobarbital, phenytoin, quinidine, rifabutin, rifampin, sildenafil, simvastatin, triazolam, warfarin... 

Clinically important, potentially hazardous interactions with amlodipine, anisindione, anticoagulants, aprepitant, atorvastatin, barbiturates, benzodiazepines, butabarbital, carbamazepine, chlordiazepoxide, clarithromycin, clonazepam, dorazepate, corticosteroids, cyclosporine, dexamethasone, diazepam, dicumarol, erythromycin, ethotoin, felodipine, flurazepam, fluvastatin, fosphenytoin, isradipine, itraconazole, ketoconazole, lorazepam, lovastatin, mephenytoin, mephobarbital, midazolam, nicardipine, nifedipine, nimodipine, nisoldipine, oxazepam, pentobarbital, phenobarbital, pimozide, pravastatin, primidone, quazepam, rifampin, secobarbital, simvastatin, St John s wort, temazepam, warfarin... 

Clinically important, potentially hazardous interactions with alfuzosin, alprazolam, amphotericin B, anisindione, antacids, aprepitant, astemizole, atorvastatin, bosentan, ciclesonide, cimetidine, clorazepate, conivaptan, cyproterone, dasatinib, dexamethasone, dicumarol, didanosine, eplerenone, erythromycin, ethotoin, fentanyl, fesoterodine, fosamprenavir, fosphenytoin, grapefruit juice, HMG-CoA reductase inhibitors, imatinib, ixabepilone, lapatinib, lopinavir, lovastatin, mephenytoin, methylprednisolone, micafungin, midazolam, nilotinib, pimozide, prednisolone, prednisone, quinidine, rifampin, rimonabant, rivaroxaban, sildenafil, silodosin, simvastatin, sirolimus, solifenacin, temsirolimus, terfenadine, tolvaptan, triazolam, vardenafil, vinblastine, vincristine, warfarin... 

Clinically important, potentially hazardous interactions with atorvastatin, carbamazepine, cisapride, cyclosporine, digoxin, dihydroergotamine, ergotamine, fesoterodine, hexobarbital, ixabepilone, lapatinib, lovastatin, metoprolol, midazolam, nilotinib, phenobarbital, phenytoin, pimozide, rifampin, rimonabant, simvastatin, sirolimus, tacrolimus, temsirolimus, tolvaptan, triazolam, warfarin... 

Rofecoxib is metabolized in the liver, primarily by cytosolic enzymes, with little renal excretion of unchanged drug. Rofecoxib at 75 mg daily modestly increased methotrexate concentrations, and at 50 mg daily modestly elevated the International Normalized Ratios (INRs) of warfarin patients. Additionally, rifampin can decrease rofecoxib concentrations. Clinically significant interactions were not observed when rofecoxib was administered with crmetidine, digoxin, oral contraceptives, or ketoconazole. Rofecoxib inhibits CYP450 1A2 and may increase serum theophylline area under the curve. 

Although a less potent inducer of CYPs than rifampin, rifabutin does induce hepatic microsomal enzymes, with its administration decreasing the half-life of a number of different compounds, including zidovudine, prednisone, digi-toxin, quinidine, ketoconazole, propranolol, phenytoin, sulfonylureas, and warfarin. It has less effect than does rifampin on serum levels of indinavir and nelfinavir. 

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