Is Viagra effective even if I don't have erectile dysfunction?

Dear Ask The Doctor: I'm 18 with no ED but want to use viagrea , is it safe?

Viagra is mainly used for erectile dysfunction; its use for recreational purposes remains a controversy. Studies imply that those with no erectile dysfunction who use Viagra have minimal effects and the effect is more of a placebo type. Conditions wherein Viagra should NOT be used are: those with severe liver and/or kidney dysfunction, recent stroke or heart attack, heart problems, low blood pressure, eye problems (retinal disorders), and those who are also taking drugs with Nitrates. Common side effects are headache, impaired vision, nasal congestion, among others. Rare but serious, life-threatening side effects are heart attacks, stroke, severe hypotension (very low blood pressure), etc. It is advisable to talk to your doctor before using it. I hope this helps and take care always.