For the safety and legality of any generic Viagra received for free, it is advisable to get advice from a medical expert or pharmacist. Sildenafil treats erectile dysfunction by increasing blood flow to the penis during sexual stimulation. Proven Effectiveness: The main ingredient in generic Viagra is sildenafil citrate, which has been extensively studied and proven to be effective in treating ED. While taking a free Viagra sample, it is acceptable to have a small amount of alcohol. Only 10 per cent of new drugs make it through trials, they often take 10 years, and cost 10 billion pounds. Ozempic, Viagra and the life-changing drugs that were created for something else Miranda Levy Posted: November 9, Last updated: November 9, For the second time this week, a drug that was invented to treat one condition has been given the green light for something else. No, generic Viagra is a prescription medication.Amazon Pharmacy: Sildenafil (Generic for Viagra, Oral Tablet).us. Account Returns& Orders. Cart. Transfer your prescription for Sildenafil (Generic for Viagra, Oral Tablet) on Amazon Pharmacy. Revatio is available as a generic under the name of sildenafil (20mg tablet). There is also a generic version of Viagra available, under the name sildenafil, in 25mg, 50mg, and mg strengths. 3. Downsides. Yes, sildenafil (the active ingredient in Viagra), manufactured by Teva, is the FDA approved generic for brand Viagra. It launched on December 11, The announcement from Teva can be seen here. It is available in each strength that the brand is available in: Being an FDA approved generic indicates that the generic is considered to .