Depression is very common - 18 million Americans are diagnosed with major depression each year. And most of them are treated with antidepressant medications. What's disturbing is that up to 70% of those given antidepressants don't take their medications regularly, for various reasons - usually they complain of side effects, such as sexual problems, weight gain and sleep upsets. The newer antidepressants - the selective serotonin reuptake inhibitors or SSRIs - have fewer side effects than the formerly widely-used tricyclic antidepressants (TCAs). However, they still produce a degree of sexual malfunction, in as many as 30% to 70% of patients taking them. Little wonder that many men on SSRIs, experiencing erectile dysfunction (ED), stop taking their medication and have a relapse in their depression.

The study summarized here was done to test the effectiveness of sildenafil (Viagra®) in treating ED related to SSRI antidepressant use. The investigators also wanted to see if sildenafil could improve other aspects of sexual malfunction - desire, orgasm, and satisfaction.

What was done

Men with depression that was in remission (i.e. they weren't actually in a severe depressive state), aged between 18 and 55, and who were taking a selective serotonin reuptake inhibitor (SSRI) antidepressant, were enrolled. They had to have had sexual problems for at least 4 weeks while they were on the antidepressant. This meant they had to attempted regular sexual activity (a minimum of once a week) and to have had satisfactory sex before the start of their depression or first taking an antidepressant. Men with other illnesses that might interfere with satisfactory sex, such as diabetes, heart disease, or substance abuse, were excluded.

Out of 117 patients screened at three university medical centers in the USA, 90 were enrolled and given either sildenafil or placebo, in a randomized fashion. Their average age was 45, and they had been taking antidepressants for an average of 27 months. They were instructed to take one study tablet approximately an hour before anticipated sexual activity, but not more than once a day. They were asked to make at least two attempts at sex each week. If necessary, the dose could be adjusted from one to two tablets. The study lasted 6 weeks.

Four reliable questionnaires were used to judge effectiveness with regard to sexual performance, in addition to a recognized measure of depression.

What was found

Of the 45 patients assigned to each treatment group, 42 on sildenafil and 35 on placebo completed the 6 weeks of the study. Based on results of the main questionnaire (evaluating overall sexual function), 55% of the men given sildenafil reported "much improved" or "very much improved", compared with only 4% of those given the placebo. The depression test showed that all the participants maintained their remission - i.e. no depressive episodes occurred.

Arousal, erectile function, ejaculation, and orgasm were all significantly improved in the men taking sildenafil, compared with those given placebo. And overall sexual satisfaction was also significantly improved with sildenafil, compared with placebo.

Headache was a fairly common side effect of sildenafil, reported by 41% of participants, compared with 10% of men taking placebo. Other minor side effects of sildenafil were indigestion and flushing.

Comment

SSRIs are prescribed for 9 out of 10 people requiring drug treatment for depression. Like older antidepressants, SSRIs can have sexual side effects in men, interfering with arousal, erection, and orgasm. Such side effects are quite likely to cause men to stop taking their medication, leading to a relapse of depression. The benefits of sildenafil in this situation are obvious. Many men can continue on their antidepressant and, by taking sildenafil, avoid drug-related upsets in their sex life.

A word of caution is necessary, however. Cause and effect between antidepressant use and sexual dysfunction was a requisite in this study, by the design of the study. In practice, on the other hand, there may be many other possible factors contributing to ED - age, diabetes, cardiovascular disease, lifestyle (smoking, alcohol, obesity, stress), and other medications. It's important that there isn't a 'rush to the little blue pill' without considering the possibility of other, treatable, contributing causes for the problem.