Voriconazole Warfarin

Drugs that may be affected by atazanavir include the following antiarrhythmics, atenolol, benzodiazepines, calcium channel blockers, cisapride, clarithromycin, ergot derivatives, HMG-CoA reductase inhibitors, immunosuppressants, indinavir, irinotecan, itraconazole, ketoconazole, oral contraceptives, PDE5 inhibitors, pimozide, rifabutin, saquinavir, tenofovir, tricyclic antidepressants, voriconazole, warfarin. 

Clinically important, potentially hazardous interactions with atazanavir, carbamazepine, clarithromycin, itraconazole, ketoconazole, nefazodone, nelfinavir, phenobarbital, phenytoin, rifabutin, rifampin, rifapentine, ritonavir, saquinavir, St John s wort, troleandomycin, voriconazole, warfarin... 

Clinically important, potentially hazardous interactions with amiodarone, amprenavir, anisindione, antacids, anticoagulants, aprepitant, atazanavir, atovaquone, beclomethasone, buprenorphine, corticosteroids, cortisone, cyclosporine, cyproterone, dabigatran, dapsone, darunavir, delavirdine, dexamethasone, dicumarol, digoxin, eszopiclone, flunisolide, fosamprenavir, gadoxetate, gestrinone, halothane, imatinib, isoniazid, itraconazole, ketoconazole, lapatinib, lorcainide, methylprednisolone, midazolam, nelfinavir, nifedipine, oral contraceptives, phenylbutazone, prednisone, protease inhibitors, pyrazinamide, ramelteon, ritonavir, saquinavir, solifenacin, sunitinib, tacrolimus, telithromycin, temsirolimus, tipranavir, tolvaptan, trabectedin, triamcinolone, triazolam, voriconazole, warfarin, zaleplon... 

Fexofenadine Imatinib Irinotecan Loperamide Methadone Midazolam Nefazodone Nevirapine Omeprazole Paroxetine oral contraceptives Phenprocoumon Setraline Simvastine Tacrolimus Theophylline Tolbutamide Voriconazole Warfarin... 

Prednisolone Progesterone Protease Inlaibitors Quinidine (1 )-Warfarin Rifampin Sertraline Sirolimus Simvastatin Tacrolimus Testosterone Trazadone Triazolam Voriconazole ... 

In one pharmacodynamic study, voriconazole approximately doubled the prothrombin time in response to warfarin. 

When a single 30-mg dose of warfarin was given to 16 healthy subjects on day 7 of a 12-day course of voriconazole 300 mg twice daily, the maximal increase in prothrombin time was about doubled. These increases in prothrombin time were still present 6 days after the warfarin dose, at which point the prothrombin time had returned to baseline with warfarin alone. Two subjects were withdrawn from the study because of an increased prothrombin time. ... 

Voriconazole is a known inhibitor of the cytochrome P450 isoenzymes CYP2C9 and CYP3A4, by which the coumarins (phenprocoumon, acenocoumarol and warfarin) are metabolised. The manufacturers advise close monitoring of the prothrombin time in any patient on a coumarin anticoagulant who is given voriconazole. Dose adjustments of the coumarin should be made accordingly. ... 

Purkitis L, Wood N, Kleinermans D, Nichols D. Voriconazole potentiates warfarin-induced prothrombin time prolongation. BrJ Clin Pharmacol (2003) 56 (Suppl 1), 24-9. 

The oral dose of voriconazole does not have to be adjusted in patients who have renal impairment. However, intravenous administration of voriconazole should be avoided in these patients as the carrier vehicle sulfobu-tyl ether P-cyclodextrin sodium can accumulate in these patients. Dosage adjustment is required in patients who have chronic hepatic impairment. As voriconazole is a substrate for a number of cytochrome P450 enzymes, a number of clinically important dmg interactions occur with dmgs including ciclospotin, tacrolimus, phenytoin, warfarin, HIV protease inhibitors and non-nucleoside reverse transcriptase inhibitors. 

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