Phenprocoumon Tolbutamide

Probe drugs used for CYP2C9 phenotyping are tolbutamide, S-warfarin, phenytoin and losartan. Diclofenac, flurbiprofen, phenprocoumone and torasemide have also been used. For safety concerns, the current preferred probe is tolbutamide, despite some risk of hypoglycemia. 

Phenprocoumon. Phenprocoumon did not alter the half-life of tolbutamide in 3 patients. ... 

The plasma levels and half-life of single doses of phenprocoumon did not differ between patients with type 2 diabetes managed by diet alone (12 patients) and those taking tolbutamide (10 patients). ... 

Dicoumarol appears to increase the effects of tolbutamide by inhibiting its metabolism by the liver. This may also be true for chlorpropantide. The increase in the anticoagulant effects of dicoumarol by tolbutamide may, in part, be due to a plasma protein binding interaction. In the case of phenprocoumon there seem to be several different mutually opposing processes going on, which cancel each other out. There is no clear explanation for most of these interactions. 

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

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