Your doctor or other health care professional can recommend one for you based on these factors, other health conditions you have and any other medicines you take. Clinical trials for MED found minimal side effects. Recent heart or blood vessel problems. As with sildenafil, a high-fat meal or alcohol keep the body from absorbing it as quickly. However, Viagra Connect is only available over the counter in the licensed strength of 50mg. Medicines that block an enzyme called CYP3A4. Vardenafil usually works for 4 to 5 hours.September 1, By Matthew Solan, Executive Editor, Harvard Men’s Health Watch Reviewed by Howard E. LeWine, MD, Chief Medical Editor, Harvard Health Publishing . Is there an over-the-counter version of Viagra? Can I get Viagra online without seeing a doctor? Currently, there are no over the counter alternatives to Viagra available. 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 effects .