The three ED medications currently on the market—Viagra, Levitra, and Cialis—all work by the same means, and they have similar side effects. The most common are headaches and facial flushing, which occur in 15% of men. Other reactions include nasal congestion, indigestion, and back pain. These side effects are mild and temporary. The most important worry about ED pills is their ability to widen arteries enough to lower blood pressure. And men who are taking nitrates should never use any of the ED pills.
Although some of the drugs' side effects may be troublesome, others may be helpful, and scientists are studying whether ED pills might help treat a variety of nonsexual problems. Viagra (sildenafil) has been on the market longest and is most studied. It's yet not clear if the other ED pills offer similar benefits, but Viagra, at least, may prove useful for some other conditions, including these:
Pulmonary hypertension: Viagra is now marketed under the name Revatio for this uncommon but serious disorder of high pressure in the blood vessels leading to the lungs.
Mountain sickness: Viagra can reduce pulmonary artery pressure at high altitude and improve the ability to exercise in low oxygen conditions.
Raynaud's phenomenon: In affected individuals, exposure to the cold triggers spasm of the small arteries that supply blood to the fingers, toes, or both, which become pale, cold, and painful. Both Viagra and Levitra have been helpful in clinical trials.
Heart disease: Studies suggest Viagra might help patients with congestive heart failure or diastolic dysfunction.