viagra for women

by Chris Steidle, MD

Viagra is what is known as a type five phosphodiesterase inhibitor. Preliminary studies in women are currently underway and while there is no answer at the present, there is information that indicates that, at least in a clinical setting, the results have been quite astounding. Some physicians have already admitted to using Viagra in women.

A Boston University study is currently underway to determine whether or not Viagra can help restore sexual pleasure among women who are taking it. Viagra’s manufacturer, Pfizer, Inc., is now in the midst of clinical trials in the United Kingdom. If studies prove successful, and many believe that they show great promise, these tests will be expanded to include thousands of women under the tough protocols required for FDA approval.

Even with Pfizer’s studies well underway, it is far too early to know anything about Viagra’s effectiveness for women or its side effects. The tests will not be completed for some time and it may be years before its approval for use in women is sought from the FDA.

Regardless of Pfizer’s results, Viagra will have no effect on a women’s libido and it is not the much-touted orgasm pill that some have claimed. ven so, there are reasons to believe that Viagra will have as profound an effect on women as it has had on men. In fact, many researchers are convinced that as prostate surgery and diabetes can lead to erectile dysfunction in men so can hysterectomies, high blood pressure and diabetes lead to circulatory problems and sexual dysfunction in women. The end result of these illnesses and conditions, researchers theorize, is that women have difficulty becoming aroused.

Here is where researchers believe Viagra will help. As in men when blood vessels in the penis become engorged with blood so that an erection occurs, it is true in women that when the blood vessels of the vagina become engorged with blood, the vagina becomes properly lubricated in preparation for intercourse. Perhaps women who have been unable to achieve orgasms may be able to climax with the help of Viagra.

Viagra is a selective inhibitor or blocker of Cyclic Guanosine Monophosphate (cGMP) specific phosphodiesterase type 5. This is a very complicated way of saying that Viagra works on an enzyme that resides in the corpus cavernosum, the spongy cylinder in the penis and the clitoris that serves as the erectile body. The difference between the penis and the clitoris is that there is a reduced ability in the clitoris to develop what is termed a veno-occlusive function. In other words, the clitoris doesn’t achieve the rigidity of the penis that turns into a structure with which to penetrate. Rather, it’s a structure that becomes swollen and helps support the protrusion of the inner structure known as the glans.

During sexual stimulation, nitric oxide is released which activates an enzyme called guanylate cyclase that acts to increase levels of cyclic GMP. The release of this enzyme causes the smooth muscles inside the spongy tissue to relax and allows blood to flow in. The end result is tumescence of the clitoris and increased vaginal blood flow. Interestingly, Viagra by itself has no effect on tissues isolated from the vagina and clitoris.

Viagra has not demonstrated any effect on bleeding or clotting in men. It does mildly inhibit phosphodiesterase type 6, the enzyme that aids in color vision by the retina. It is for this reason that a very small percentage of men will notice mild visual side effects, usually blue tinted vision, when taking Viagra. Rapidly absorbed in the blood stream when taken in pill form, Viagra levels peak in the human body plasma within one hour and often in as little as thirty minutes. When taken with a high fat meal, its clinical effectiveness is substantially reduced. In other words, the effect of the drug is severely diminished when taken with a heavy meal. When properly administered, however, Viagra proves to be remarkably effective, and significantly, it has a relatively long half-life, the length of time the drug remains in the body (up to four hours). Extensive studies on the drug conclude that it is broken down by the liver and most of it is then excreted from the body in the feces. Viagra has been studied extensively in elderly patients as well and no additional problems were noted. However, this population did exhibit higher serum levels of the drug and its metabolites due to more difficulties with excretion.

Viagra is available in two strengths, 50 and 100 mg. For most, a started dosage of 25 to 50 mg is recommended, although this dose may be reduced in elderly patients who have severe liver disease or renal failure. Additionally, patients who have been prescribed Erythromycin or Ketoconazole should probably start with lower doses. The drug metabolizes easier in some men than others and this is an important fact when considering the initial dosage. In any event, patients are strongly advised never to take any form of nitroglycerin prior to or especially during the period in which they are taking Viagra as results can be tragic and even fatal. Indeed, many of the deaths attributed to Viagra have been linked to the patient’s use of nitroglycerin. Be advised that those taking nitrate therapies in any form should steer away from taking Viagra.

January 2000