HORMONES -
ERECTILE DYSFUNCTION

It is estimated that Erectile Dysfunction (ED) affects more than half of all men over 40 years of age, or 140 million men worldwide. However, only one in 20 receives medical treatment, demonstrating the clear need for additional therapies in this area.  Sildenafil (Viagra^®), the only oral medication that is currently commercially available  to treat ED, is not always successful and requires approximately one hour to exert its effect. Additionally, sildenafil has been associated with a variety of side effects and drug interactions.

Two other medications, tadalafil and vardenafil, are currently under research and development. Drug-related adverse effects, with headache in up to 23% of patients (placebo, 17%), indigestion in up to 11% (placebo, 7%), and back pain in up to 4.7% (placebo, 0%) were mostly mild to moderate.  Neither serious drug-related cardiovascular problems nor color vision disturbances were encountered. These drugs remain active in the body for a longer period of time than sildenafil.

Apomorphine is another medication that works on areas in the brain known to be involved in erectile function. More than 5,000 men with ED participated in clinical trials assessing the safety and efficacy of apomorphine, which is taken sublingually (under the tongue), dissolves rapidly, is effective in approximately 60% of patients, and results in an erection in about 20 minutes. However, in the U.S., its New Drug Application was withdrawn amid concerns of patients who had fainted after taking the medication, decreases in blood pressure when apomorphine was taken  concurrently with nitrates, and potential interactions with alcohol.  Nausea was reported in 16% of patients taking low doses (2 mg). Apomorphine is commercially available for the treatment of ED in Europe (Apo®, Uprima®).