For many years, there were only three dominant erectile dysfunction drugs – Viagra, Levitra, and Cialis. Viagra, manufactured by Pfizer Inc., was approved by the FDA in March 1998. Levitra, manufactured by Bayer Pharmaceuticals Corporation, was approved in August 2003. Cialis, manufactured by Eli Lilly ICOS, was approved in November 2003.
But now, after nearly a decade, there is another effective option – Stendra. Stendra (avanafil) has been available since April 2012. Like the other drugs, Stendra increases the flow of blood into the penis so that when a man is sexually stimulated, he can get and maintain an erection. However, Stendra appears to have a competitive advantage in the category of onset of action. Its developer (Auxilium Pharmaceuticals Inc.) advertises that Stendra is the “first and only erectile dysfunction drug that can be taken as early as 15 minutes before sexual activity”.
When Stendra was first approved by the FDA in April 2012, its label recommended administration approximately 30 minutes before sexual activity. However, based on the results of an additional study, the FDA approved a new label in September 2014. The additional study, which compared Stendra to placebo in 440 patients in the United States, demonstrated that Stendra enabled many men to get an erection sufficient for sexual intercourse within 15 minutes of administration.
How does this compare to the onset of action of the other erectile dysfunction drugs? Viagra typically takes effect within 30-60 minutes, although the effect may be delayed if taken with food. Levitra typically takes effect within 30 minutes, although the effect may be delayed by a fatty meal. Cialis typically takes effect within 30-45 minutes (not affected by food). For couples who prize sexual spontaneity, Stendra certainly seems to have a competitive edge. However, the low-dose version of Cialis for daily use has an even greater advantage. With this medication, there is a steady supply of the drug in the bloodstream, making sexual activity a possibility without any advance planning at all.
The duration of effectiveness for Stendra is approximately 6 hours. This is slightly better than Viagra (which lasts about four to five hours) and Levitra (which lasts about 5 hours), but inferior to Cialis, which has a window of opportunity ranging from 24 to 36 hours.
In most other categories, Stendra is very similar to Viagra, Cialis, and Levitra. All four medications are in a class of drugs known as PDE5 inhibitors, which augment the effect of nitric oxide, a molecule that is released during sexual stimulation. Nitric oxide triggers the blood vessels of the penis to open, thereby increasing blood flow and allowing a man to develop and maintain an erection.
The side effects of Stendra are similar to those of Viagra, Levitra, and Cialis. When the drugs are used properly, most side effects tend to be relatively mild and disappear after a few hours. The most common side effects with Stendra are headache, facial flushing, nasal congestion, sore throat, and back pain. Extremely rare but very serious side effects with Stendra include sudden vision loss in one or both eyes, sudden hearing decrease or hearing loss, and an abnormally long and painful erection that will not go away (priapism). If any of these conditions occur, Stendra should be discontinued immediately and emergency medical assistance should be obtained.
Stendra (as well as Viagra, Levitra, and Cialis) should not be taken by men who take nitroglycerin or other medicines containing nitrates. Just like PDE4 inhibitors, nitrate medicines cause blood vessels to enlarge in diameter. This increases blood flow to the heart and results in a drop in blood pressure. The combined effects of the medications could cause an unsafe drop in blood pressure, resulting in dizziness, fainting, and even a heart attack. Nitrate medicines include nitroglycerin and isosorbide (both used to treat chest pain and other symptoms of angina). Nitrates are also contained in recreational drugs called “poppers” and in some air fresheners and video head cleaners which are inhaled to heighten sexual pleasure.
Men who have had a heart attack or stroke and those with certain medical conditions (e.g., poorly controlled high or low blood pressure, bleeding problems, liver disease, kidney disease or kidney dialysis, severe vision loss, and stomach ulcers) should discuss these conditions with their healthcare provider before taking Stendra.
Stendra is available in dosages of 50 mg, 100 mg, and 200 mg. The recommended starting dose is 100 mg. Based on efficacy and/or tolerability, the dosage may be increased to 200 mg or decreased to 50 mg. The 50 mg dosage is recommended for patients on alpha blockers (which are sometimes used to treat prostate problems or high blood pressure). The 50 mg dose is also recommended for patients taking CYP3A4 inhibitors. It is important to note that the 100 mg and 200 mg dosages can be taken as early as 15 minutes before sexual