An enzyme-inhibiting drug used in the treatment of male impotence.
An anti-impotence drug. Sildenafil citrate (Viagra) is prescribed for men who have difficulty obtaining or maintaining an erection during sexual intercourse, a condition called erectile dysfunction, or impotence. Sildenafil citrate works by blocking the action of an enzyme that causes a reduction in blood flow to the penis, thus increasing the blood supply. Sildenafil citrate works only in men whose erectile dysfunction is caused by poor blood flow to the penis.
An oral drug better known to the public as Viagra and Revatio for treating erectile dysfunction of the penis. It was developed to treat angina pectoris but during clinical trials, patients reported that they were having more erections than before taking the drug. Clinical trials were then conducted and the drug found to be effective for many men with erectile dysfunction due to conditions such as high blood pressure, high concentrations of cholesterol, diabetes mellitus, surgery and psychological disorders. Among side-effects, headache was the most common; others included facial flushing, indigestion and a stuffy nose. The drug is one of the vasodilators, so blood flow to the penis is enhanced. It works in response to sexual stimulation and has no properties as an aphrodisiac; nor does it provoke sexual fantasies. Sildenafil must not be taken with drugs containing nitrates such as glyceryl trinitrate or isosorbide trinitrate as the subject may suffer a sudden fall in blood pressure. Nitrates inhaled for recreational use (poppers) have a similar effect. There are restrictions on how NHS doctors may prescribe these drugs.