The most serious side effects of Viagra are usually related to lowered blood pressure. By Steven Gange, MD, FACS

Maybe. The most serious side effects of Viagra are usually related to lowered blood pressure. For a relatively healthy, average male, two studies suggest that a moderate dose of alcohol (a mean maximum blood-alcohol level of 0.08% or about two drinks within an hour before using Viagra) combined with a 50-milligram Viagra tablet does not lower blood pressure significantly, according to the drug manufacturer Pfizer. On the other hand, not all men on Viagra are healthy, and sex itself can create a wide spectrum of physiological responses.

Specifically, Pfizer studies have shown that men with very high or very low resting blood pressures (above 170/110 or below 90/50) and those with heart disease may be at increased risk for problems when using Viagra. This may be due in part to the fact that sexual activity by itself is potentially risky to someone with a heart condition.

Also, the effects of sexual activity on the heart and blood pressure depend on the circumstances: More arousal means greater effect. Alcohol can also enhance the effects of sexual stimulation. So, at least in theory, the combination of alcohol, Viagra, and sexual arousal could become dangerous for a man with a blood-pressure problem.

We know without doubt that men taking any form of drug containing nitrates (such as nitroglycerin and a long list of other medications -- ask your doctor or your pharmacist, or review the Viagra package insert for more information) should not take Viagra because of the potential for life-threatening low blood-pressure problems. While Viagra is generally safe, other less-serious side effects can also occur, including headache, nausea, facial flushing, visual disturbances, and, in rare cases, priapism (a prolonged, painful erection).

If you are otherwise healthy and have no significant side effects with Viagra, a small amount of alcohol is unlikely to cause problems. But if you have blood-pressure problems or heart disease, or if you take blood-pressure medication, you should avoid combining alcohol and Viagra.