FOR IMMEDIATE RELEASE
CONTACT: Catherine Seigerman, U.Va. Health System Media Relations804-924-5679
SEXUAL DYSFUNCTION RESULTS FROM MOST ANTI-DEPRESSANT DRUGS, SAYS U.VA. RESEARCHER
CHARLOTTESVILLE, Va., May 3 -- All but two of the newer anti-depressant drugs cause significant sexual dysfunction (SD), according to results of a study conducted by Dr. Anita H. Clayton, associate professor and vice chairman, Department of Psychiatric Medicine, University Virginia Health System and Dr. James Pradko, a primary care physician in New Baltimore, Mich.
The study, funded by GlaxoSmithKline, included 6,297 patients reporting data to their primary care physicians at 1,101 clinics across the United States. The responses were based on a questionnaire designed by Clayton at U.Va. The data is being presented in a poster format at the American Psychiatric Association annual meeting on Tuesday, May 8 in New Orleans.
"Other studies may have included a few hundred people, but no more than 1,500. Not only did the U.Va. study have nearly 6,300 participants, it is the first study to include all of the newer anti-depressants manufactured in the U.S. since 1988," Clayton said.
"This may be the definitive study of SSRI SD effects, and our questionnaire may be very good for use as new drugs come out," she said.
The study found that patients taking either bupropion SR (Wellbutrin) or nefazodone(Serzone) had a statistically significantly lower prevalence of SD than patients taking fluoxetine (Prozac), paroxetine (Paxil), sertraline (Zoloft) or venlafaxine XR (Efflexor). In addition, patients taking bupropion SR had a significantly lower prevalence of SD than patients taking citalopram (Celexa) or mirtazapine (Remeron). Patients taking another type of Wellbutrin, bupropion IR, also had a significantly lower prevalence of SD than patients who were taking paroxetine, sertraline or venlafaxine XR. Patients taking fluoxetine had a lower prevalence of SD than patients taking paroxetine. No other differences among antidepressants in the prevalence of SD were statistically significant.
Wellbutrin and Serzone affect the brain in a different way from the other drugs in the study, Clayton said, because they bind to cells at a different receptor site.
Study participants had to be at least 18 years old, have been sexually active at some time during the last 12 months, and be willing to discuss his or her sexual functioning with the physician. Seventy percent of people asked agreed to participate in the study -- a much higher participation rate than expected, Clayton said. This rate suggests that the majority of patients are not hesitant to discuss sexual functioning with their physicians when directly questioned about it.
Physicians had estimated a 20 percent prevalence rate of SD among patients taking antidepressants. However, the questionnaire revealed that 37 percent of patients were found to have a clear-cut SD condition. The proportional rate of antidepressant use in the study resembled antidepressant prescribing practices by primary care physicians in the United States, Clayton said.
Risk factors for SD included increasing age, higher daily antidepressant dose, being married, education level less than a college degree, employment status other than full-time, having a comorbid illness associated with SD, or taking any concomitant medication. Patients who did not have a history of sexual enjoyment, had low interest in sexual functioning, or had a history of SD with previous antidepressant therapy were also at greater risk for SD. SD risk also was significant among those who smoked six to 20 cigarettes per day.
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May 3, 2001
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