Nefazodone Warfarin

Carbamazepine + phenytoin, tricyclic antidepressants, typical neuroleptics, valproate, clonazepam, warfarin, nefazodone and propoxyphene —> reduced plasma concentration of carbamazepine due to increased metabolism. 

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 atazanavir, carbamazepine, clarithromycin, itraconazole, ketoconazole, nefazodone, nelfinavir, phenobarbital, phenytoin, rifabutin, rifampin, rifapentine, ritonavir, saquinavir, St John s wort, troleandomycin, voriconazole, warfarin... 

Potentially clinically significant interactions include the tendency for fluvoxamine to increase circulating concentrations of oxidatively metabolized benzodiazepines, clozapine, theophylline, and warfarin. Sertraline and fluoxetine can increase levels of benzodiazepines, clozapine, and warfarin. Paroxetine increases levels of clozapine, theophylline, and warfarin. Fluoxetine also potentiates tricyclic antidepressants and some class 1C antiarrhythmics with a narrow therapeutic index (including encainide, flecainide, and propafenone). Nefazodone potentiates benzodiazepines other than lorazepam and oxazepam. 

Fluvoxamine inhibits liver drug-metabolizing enzymes. Dosages of alprazolam, theophylline, and warfarin must be reduced if any of these drugs are given concomitantly with fluvoxamine. Nefazodone may also decrease the metabolism of benzodiazepines, and venlafaxine may inhibit haloperidol metabolism. The answer is (B). 

CYP2C9 Cyclosporine, Ifosfamide, Etoposide Nefazodone, Losartan, Warfarin, Tamoxifen, Phenytoin... 

In a one study, nefazodone decreased the level of A-warfaiin by just 12% and did not alter the prothrombin ratio. A handful of case reports describe a moderate reduction in the anticoagulant effects of warfarin caused by trazodone. 

In one study, 17 healthy subjeets given warfarin to achieve a prothrombin ratio of 1.2 to 1.5 for 14 days were then given nefazodone 200 mg or plaeebo every 12 hours for a further 7 days. The only pharmaeokinetie changes were a 12% decrease in the AUC and maximum serum levels of S-warfarin. No changes occurred in the prothrombin ratios. ... 

The incidence of this interaction is unknown. All the evidence suggests that some patients require a moderate inerease in warfarin dose when starting trazodone. Be aware of this interaetion in all patients taking warfarin if trazodone is started or stopped, and adjust the dosage if necessary. The interaction can occur within a few days. The elinieal relevance of the 12% decrease in 5-warfarin levels see with nefazodone is likely to be minor. The authors of the study eoneluded that no ehange in warfarin dose is likely to be required on eoneurrent use. ... 

Salazar DE, Dockens RC, Milbrath RL, Raymond RH, Fulmor IE, Chaikin PC, Uderman HD, Pharmacokinetic and pharmacodynamic evaluation of warfarin and nefazodone coadministration in heal y subjects. J Clin Pharmacol (1995) 35, 730-8. 

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

---