Terms and conditions of use. Grapefruit juice: Grapefruit juice can increase the amount of Viagra Sildenafil in your bloodstream. The contents herein are for informational purposes only. Blood pressure may suddenly drop to life-threatening levels if Viagra Sildenafil is taken with any nitrate-containing medication e. We’re Here for You Our pharmacists are happy to answer your questions. Alcohol: Consumption of alcohol in large amounts may decrease the ability to get an erection and may also temporarily decrease blood pressure, causing dizziness and fainting.Sildenafil is a generic drug, which is an exact copy of the active drug in a brand-name medication. The generic is considered to be as safe and effective as the original drug. And generics tend to. Typical dosing for Sildenafil (Viagra) The typical dose is to take 50 mg of sildenafil (Viagra) by mouth, about 1 hour before sex, as needed. The maximum recommended dose is . Product (s) Viagra mg Tablets 4 (Repat Authority Script) – Sildenafil. Private Prescription Price. $ Discounted PBS Price. -. Concession PBS Price. $ Safety Net Price.