Tolbutamide Aprepitant

Aprepitant may be affected by paroxetine, CYP2C9 substrates (eg, phenytoin, tolbutamide, warfarin), CYP3A4 substrates (eg, alprazolam, cisapride, dexamethasone, docetaxel, etoposide, ifosfamide, imatinib, irinotecan, methylprednisolone, midazolam, paclitaxel, pimozide, triazolam, vinblastine, vincristine, vinorelbine), and oral contraceptives. 

APREPITANT ANTIDIABETIC DRUGS-TOLBUTAMIDE 1 tolbutamide levels Aprepitant t CYP2C9-mediated metabolism of tolbutamide Monitor blood glucose closely... 

In a study in 12 healthy subjects aprepitant (125 mg on day one, then 80 mg daily on days 2 and 3) decreased the AUC of a single 500-mg dose of tolbutamide by 23%, 28%, 15%, when given on days 4, 8, and 15, respectively, when compared with 12 subjects not given aprepitant. ... 

Aprepitant is an inducer of the cytochrome P450 isoenzyme CYP2C9 by which tolbutamide is metabolised. It therefore increases tolbutamide metabolism, which leads to a reduction in tolbutamide levels. However, the clinical relevance of these small changes has not been assessed. The manufacturer recommends caution when both drugs are given. ... 

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