VIAGRA should not be utilised with REVATIO or with other PAH therapies containing sildenafil or almost every other PDE5 inhibitors (like Adcirca® [tadalafil])Effects of Other Medication on VIAGRA Sildenafil metabolism is principally mediated by CYP3A4 (key route) and CYP2C9 (insignificant route). Consequently, inhibitors of these isoenzymes may po