As far as safety, the current consensus is that it’s safe to drink in moderation when you take Viagra. For men, “in moderation” means the equivalent of two drinks. One drink translates as
• One 12-oz. beer (with 5% alcohol)
• One 5-oz. glass of wine (with 12% alcohol)
• One 1.5-oz drink of hard liquor (with 40% alcohol, the equivalent of 80 proof)
It’s important to understand, however, that by consuming alcohol (even in moderation) with Viagra, you’re working against what the drug is trying to do. If you’ve ever been unable to perform sexually after having overindulged in alcohol, you know that alcohol interferes with your ability to have an erection.
Viagra works by allowing more blood to flow into the penis during sexual stimulation, but it’s not magic, and how well it works can be affected by how much you drink. The safest thing in terms of sexual performance would be to abstain from alcohol while drinking Viagra. Otherwise, be sure that you drink in moderation, or you take all sorts of risks, including the risk of the medication not working very well.