Inform your doctor if you’re allergic to any drugs so that he or she can determine whether you may be allergic to Viagra. [1] X Research source Let your doctor know what other medications you’re taking, including herbal supplements.
Viagra pills are available in either 25 mg, 50 mg, or 100 mg tablets. The maximum recommended dose is 100 mg. Do not take more than this at once.
Redness and heat in the neck and face Headaches Stuffy nose Memory problems Upset stomach or back pain
An erection that is painful or lasts 4 hours or longer Vision loss Chest pain Irregular heartbeat Feeling lightheaded Swelling in the hands, ankles or feet Nausea or a general ill feeling
