Effects of Other Medication on VIAGRA Sildenafil metabolism is principally mediated by CYP3A4 (main route) and CYP2C9 (insignificant route). Hence, inhibitors of these isoenzymes may lessen sildenafil clearance and inducers of these isoenzymes may increase sildenafil clearance.In most cases, Viagra will slightly lessen your hypertension. This doesn