Avoid Inappropriate Prescribing of Viagra, Experts Say
By Theresa Waldron
[Medical Tribune: Family Physician Edition 39(11): 1998. c 1998 Jobson
Healthcare Group]
Because of the enormous popularity of sildenafil (Viagra, Pfizer), the
drug recently approved for treating erectile dysfunction (ED) in men, physicians have been inundated with patient requests for prescriptions for the drug. Although sildenafil offers new hope to many men with ED, it is important not to prescribe it indiscriminately, according to experts who are familiar with the medication.
Sildenafil appears to be safe and effective when used appropriately. In premarketing trials involving more than 4,000 men with mild to complete ED, rates of successful sexual intercourse with sildenafil were about 70%, compared with 29% among men taking placebo. The average age of the men studied was 55. Men with ED from organic causes such as diabetes, spinal-cord injuries and prostate surgery were part of the study, as well as men with psychogenic ED stemming from problems such as depression.
The most common side effects of the drug were headache, facial flushing and indigestion. Sildenafil is contraindicated in patients on nitrates of any form, such as nitroglycerin, because they increase the drug's hypotensive effects. Sildenafil's wholesale price is about $7 per tablet. The recommended dose is 50 mg taken one hour before sexual activity, though it may be prescribed in doses up to 100 mg and be taken from a half hour to four hours before sexual activity.
James Barada, M.D., director of the Center for Male Sexual Health in
Albany, N.Y., said he has heard anecdotal reports of sildenafil being used inappropriately for many indications.
"Any time a drug comes out for one particular indication, you stretch
the envelope as you are trying to learn new things and new applications for it," he said. "Off-label uses are very common in medicine. However, what we're doing here is to take a proposed mechanism of action for a drug and then apply it without much in the way of study or research. This may translate into bad medicine."
Neil Brooks, M.D., a primary-care doctor in Rockville, Conn., who is
president of the American Academy of Family Physicians, said he is writing an average of about five prescriptions a day for sildenafil. The typical patient is middle-aged and has had ED for some time. Usually, the cause of ED is organic, such as diabetes. A few patients without ED ask for sildenafil for the wrong reasons.
"Some patients are requesting it not because they are impotent, but
because they want to enhance performance," Dr. Brooks explained. "Obviously, that's not the intended purpose of the medication."
What follows are examples of off-label uses of sildenafil that Dr.
Barada said he has heard about anecdotally, either from colleagues or in news reports:
Some physicians are prescribing it to women with problems with
sexual arousal or dyspareunia, even though sildenafil has not been
studied in women. A study of sildenafil in women is starting in Europe, but those results will not be available for some time, Dr. Barada noted.
Sildenafil is being used to treat sexual dysfunction such as
delayed ejaculation or decreased libido in men taking selective serotonin reuptake inhibitor (SSRI) antidepressants such as fluoxetine (Prozac, Dista).
"If they had no erectile dysfunction prior to their therapy, when they
use the Prozac, it's not a matter of a problem with the end organ, it's [a problem] that is central in nature," Dr. Barada said. "Therefore, you would postulate that there would be no effect of the medication. Delayed ejaculation isn't really erectile dysfunction, it's ejaculatory dysfunction, and Viagra is not indicated for treatment of ejaculatory dysfunction."
Some men with little or no ED are using sildenafil daily to
"prevent" ED from occurring.
"The idea is you will take this drug, you will enhance nocturnal
erections, which will wash out all the bad things and prevent further problems from occurring," Dr. Barada said. "If [men] don't need the Viagra to have intercourse, it's not something they should use prophylactically to prevent further impairment from occurring."
Sildenafil is being prescribed for psychogenic ED, usually related to relationship conflict with a sexual partner.
"A good erection doesn't fix a bad relationship," Dr. Barada said. "We
understand that most erection difficulties are organic in nature, but there is a smaller population that will respond to relationship counseling. Viagra may be appropriate in conjunction with counseling, but it shouldn't be used as a substitute for counseling."
Besides ensuring that sildenafil is being prescribed appropriately,
patients should receive some type of workup before receiving the drug, Dr. Barada added. Product literature for the drug recommends a thorough medical history and physical exam to rule out organic causes of ED such as diabetes or atherosclerosis. That should include a complete blood count, chemistry profile, lipid levels and a glucose tolerance test if diabetes is suspected, he said.
Physicians also should remember that sildenafil works best in men with
partial ED or who have difficulty maintaining an erection, Dr. Barada said.
[article copied from a post at support.impotence newsgroup]
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