Online pharmacies don’t always hold up to scrutiny, either. Generic versions of sildenafil, vardenafil and tadalafil are available. Oral medicines for ED usually work well and cause few side effects. You can take this medicine with or without food 30 minutes before sex, depending on the dose. Men may take it socially with other drugs, rather than for treatment of a medical condition. The danger comes from taking it with other drugs or getting it from someone without a medical license. If you don’t have a prescription, the drug itself — not just how you use it — may be a problem.Stick to reputable sites and pharmacies you can trust. Is there an over-the-counter version of Viagra? Can I get Viagra online without seeing a doctor? Sildenafil (Viagra). This medicine works best when you take it on an empty stomach an hour before sex. The body takes longer to absorb it after a high-fat meal or alcohol. Its . Can I buy generic Viagra without a prescription? No. In most countries, including the United States, Viagra is not available without a prescription.