When a man has erectile dysfunction (ED), he cannot achieve or maintain a firm erection. ED is also called "impotence." About one in every ten men has ED or some degree of impotence.
Most erectile dysfunction has a physical cause. The side effects of diabetes and prostate cancer treatment can reduce or prevent blood flow and nerve impulses to the penis. So can pelvic injury and the side effects of drugs. Only about 10% of impotence has a psychological cause.
Almost all impotence can be treated. Among all forms of treatment, drug therapy has become the most popular.
Sildenafil, widely known as Viagra, is the main drug used to treat ED. It is one of the most popular drugs in recent history. Viagra treats erectile dysfunction by increasing the capability for blood flow to the penis.
Sildenafil is a "PDE5 inhibitor." Most of the body's PDE5 enzyme is in the penis. Sildenafil allows the enzyme produced during sex to last longer. The longer it lasts the better the chance for increased blood flow and an erection.
Viagra is unique because it only works when a man is sexually stimulated. Stimulation engages the PDE5 "action" and helps cause an erection.
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In most cases, Viagra works best on an empty stomach and when it is taken about an hour before attempting an erection. Unfortunately, this means that sexual intercourse often must be planned at least an hour in advance. This planning process and delay can hamper romantic spontaneity.
It is recommended that Viagra be taken only once every 24 hours. A man must be sexually stimulated for the drug to help him get an erection. If a man takes Viagra but does not have sex, his body naturally eliminates the drug with no side effects over a 6-10 hour period.
Viagra works for about 60-70% of the men who take it. Combined with sexual stimulation, the drug gives the user a rigid and long-lasting erection.
Viagra does not work as well for men with ED caused by prostate surgery and diabetes, where the nerves and vascular system may be compromised. Some men only get a partial erection without acceptable rigidity. Sometimes the drug does not work at all.
A man who has been prescribed blood pressure medications should not use Viagra. The following medical or physical conditions also make the use of Viagra inadvisable:
A doctor must prescribe Viagra. Certain prescription and over-the-counter drugs can interact with Viagra. It is always important to tell your doctor about all the medications you are taking.
Two additional PDE5 inhibitors, one from Bayer and one from Lilly/Icos, are in clinical trials. It is likely they will be marketed globally in the future. These drugs actually work in a similar way to sildenafil. Most early clinical data shows little improvement for those who failed on Viagra.
These new drugs reportedly are faster-acting, producing an erection in less than the hour required by Viagra. They also may have a longer "half life," so users may benefit from these erectile dysfunction drugs over a longer period of time.
Alprostadil - This is the active medication in the urethral suppository known as MUSE. It also can be used for penile injection therapy.
Papaverine - May be used for penile injection therapy.
Testosterone supplements - These supplements can reduce impotence in some men who have low levels of natural testosterone. But only about 4% of men have this problem. Side effects may include fluid retention, prostate enlargement, and liver damage. Supplements can be administered orally, by patch, or by injection.
Yohimbine tablets - Yohimbine is an organic alternative that provides minimal positive results. Doctors occasionally prescribe this drug for intermittent erectile dysfunction. The drug can sometimes stimulate desire and improve the quality of the erection. Common in the early 1990's, yohimbine use has dropped greatly since Viagra was released.
A man takes Yohimbine three times per day for 4-6 weeks to test its effect. About 15-20% of users report some success. However, stopping the tablets may bring back impotence. There can also be side effects. These include headaches, sweaty palms, dizziness, and nausea.
Phentolamine - This drug is also used for penile injection therapy. A tablet form using phentolamine as an active ingredient was recently reviewed in clinical trials. Concerns about use of the tablet form have delayed introduction.
Oral Apomorphine - This is a sublingual (under the tongue) form of medication that affects the brain signals to the penis, versus the blood flow as in PDE5 drugs. Uprima is available outside the United States. Apomorphine offers a positive opportunity for patients who may have cardiovascular disorders such as hypertension and coronary artery disease, and therapy may include antihypertensives or nitrate medications. Early clinical data shows side effects are more prevalent than with Viagra; the most common side effects are headaches, nausea, and dizziness.
"I have just tried...Viagra. This... dose acted like a 'turbo-charger,' and made me feel 19 again. It brings a whole new dimension to your sex life and a smile on your partner's life."
Patient message posted on the Web
"Viagra worked just fine for me and I got a really strong erection that lasts. Within a five hour period I can have multiple erections. Not bad for a 62-year-old man."
Patient message posted on the Web
"Viagra does not work for me as I have had a radical prostatectomy for prostate cancer."
Patient message posted on the Web
"John, my husband, has been diabetic for as long as 18 years. He started having problems with keeping an erection so his doctor put him on the 50 mg pill and I must say Viagra works! Our love life has never been better!"
Sexual partner message posted on the Web