Outcomes of Other Medicines on VIAGRA Sildenafil metabolism is principally mediated by CYP3A4 (main route) and CYP2C9 (minor route). Hence, inhibitors of those isoenzymes may lessen sildenafil clearance and inducers of such isoenzymes could maximize sildenafil clearance.Furthermore, N-desmethyl metabolite AUC and Cmax values substantially enhanced