Some types of medications for impotence (such as Viagra, Levitra, or Cialis) are taken orally. While oral forms improve response to sexual stimulation, they do not trigger an automatic erection. Additional types of oral drugs are being tested for safety and effectiveness. Other kinds of medicines are injected into the penis or inserted into the urethra.
Medication for impotence (also known as erectile dysfunction, or ED) can be taken orally (by mouth), injected directly into the penis, or inserted into the urethra at the tip of the penis.
In March 1998, the U.S. Food and Drug Administration (FDA) approved Viagra® as the first pill to treat impotence. Since that time, a few other drugs -- vardenafil hydrochloride (Levitra®), tadalafil (Cialis®), orally disintegrating vardenafil (Staxyn™), and avanafil (Stendra™) -- have also been approved as impotence treatments.
Additional types of oral medicines are currently being tested for safety and effectiveness.
Viagra, Levitra, and Cialis all belong to a class of impotence medication called phosphodiesterase (PDE) inhibitors. Taken an hour before sexual activity, this drug works by enhancing the effects of nitric oxide, a chemical that relaxes smooth muscles in the penis during sexual stimulation and allows increased blood flow. While oral medicines improve the response to sexual stimulation, they do not trigger an automatic erection as injections do.
None of these PDE inhibitors should be used more than once a day. Men who take nitrate-based drugs, such as nitroglycerin for heart problems, should not use any impotence drug that comes in pill form because the combination can cause a sudden drop in blood pressure.
Also, tell your doctor if you take any drugs called alpha blockers, which are used to treat an enlarged prostate (BPH) or high blood pressure. If you do, your doctor may need to adjust your medication for impotence. Taking a PDE inhibitor and an alpha blocker at the same time (within four hours) can cause a sudden drop in blood pressure.