PDE-5 inhibitors effective in men on antidepressants

Montreal-Phosphodiesterase type-5 inhibitors appear to be effective in treating erectile dysfunction in men who are also receiving pharmacologic treatment for depression. A retrospective study presented here at the Canadian Psychiatric Association annual meeting that looked specifically at tadalafil (Cialis) demonstrated that the drug was effective in improving erections and achieving intercourse in this population.

Dr. Lee noted that sildenafil citrate (Viagra) and tadalafil have been studied for the treatment of selective serotonin reuptake inhibitor (SSRI)-induced ED. Vardenafil (Levitra) has been studied in men with mild untreated depression and ED but not specifically those being treated with SSRIs. However, he said there appears to be a class effect, and any of the three agents would likely be effective treatments for depression-induced ED.

The mean age of participants was 56 years (range, 27 to 78 years). Initially, 82 subjects were placed in the treatment arms, and 29 received placebo. The vast majority of subjects in both treatment arms and in the placebo arm experienced ED for a year or more. Their severity of ED was categorized as mild, moderate, or severe, based on Erectile Function Domain Score.

80% experience improvement Some subjects also presented with other comorbid conditions such as diabetes mellitus, hyperlipidemia, and hypertension. They were randomized to receive either 10 mg of tadalafil (19 men), 20 mg of tadalafil (60), or placebo (27). Five patients withdrew from the study because of adverse events or lack of efficacy. The most common side effect was headache, followed by back pain, nasopharyngitis, and limb pain.

Researchers used several measurement tools to determine whether improvements in erections occurred, including a Global Assessment Questionnaire (GAQ), the International Index of Erectile Function (IIEF), the Erectile Function (EF) domain score, and the Sexual Encounter Profile (SEP) diary.

Using the GAQ, of the 79 patients on both dosages of tadalafil, 66 (80%) said they experienced improvement in erections, while 10 of 29 patients on placebo (30%) said they experienced improvement in erections, a difference that was statistically significant (p<.001).

The mean IIEF Erectile Function score was 22.1 in the two drug treatment arms and 14.5 in placebo recipients. The SEP diary, which indicated successful intercourse attempts, revealed a mean per-patient success rate of 58% when combining the two tadalafil study arms and 25% among placebo patients, also a statistically significant difference.

"This study shows that ED can be treated in men with depression, just as it can be treated in men without depression," said Dr. Lee. "Viagra, Levitra, and Cialis can be an antidote to ED if it is induced by antidepressants. The medication is very safe to take as well. We have seen no cross-reactivity or increase in side effects."

Helps ensure compliance Pierre Assalian, MD, associate professor of psychiatry at McGill University and director of the Human Sexuality Unit at the McGill University Health Centre, Montreal, agreed that PDE-5 inhibitors offer a benefit in correcting erectile dysfunction caused by antidepressants.

"When we administer SSRIs, many patients do develop sexual side effects," said Dr. Assalian. "In order to ensure compliance of the antidepressants, it's key that we treat the ED, so that patients can have sexual functioning. Patients will often abandon treatment with antidepressants because their sexual functioning is affected."