«questo era sul NYTimes di martedì scorso. Si parla anche qui di effetti collaterali di un antidepressivo della famiglia degli SSRI...ma non una parola riguardo al rischio emorragie. Unico problema affrontato: il farmaco provoca calo del desiderio sessuale. Ma per fortuna finisce con una buona notizia: altra pillola insieme all'antidepressivo e l'orgasmo è ancora meglio di prima della depressione!!!»New York Times 25.1.05
A Pill's Surprises, for Patient and Doctor Alike
By RICHARD A. FRIEDMAN, M.D.
As a psychopharmacologist, I know that every patient responds slightly differently to medication. But it wasn't until I met Susan that I understood just how differently.
She'd come to see me because she was depressed, and I'd successfully treated her with a course of Zoloft, a popular antidepressant. But as often happens, Susan's desire for sex had vanished along with her depressed mood.
"I kind of miss it, but I feel really bad for my husband, who's getting very frustrated," she said.
The sexual side effects of antidepressants like Zoloft and Prozac - the class of drugs known as selective serotonin reuptake inhibitors, or S.S.R.I.'s - are well known. The drugs frequently cause diminished libido, erectile dysfunction in men, and delayed orgasm or an inability to climax at all in women. The same flooding of the brain with serotonin that alleviates depression leads to sexual effects in many patients.
Early on, the rates of sexual side effects from S.S.R.I.'s reported in the medical literature were quite low, in the range of 10 percent to 20 percent. But clinicians knew better. Most of their patients reported some sexual effects, and it quickly became clear that the early reports were wrong.
The reason for this error was simple. Early clinical trials of the drugs did not look for sexual side effects; they just recorded problems that patients spontaneously reported. Because most patients are reluctant to bring up any sexual side effects on their own, the researchers got the false impression that these drugs had little effect on sexuality. When the subjects were specifically asked about sexual side effects, the rates rose to 40 percent to 50 percent.
Susan fell into that unlucky percentage, and she asked me if anything could be done. There were three possible approaches, I told her. She could stop the drug from time to time, a strategy that might temporarily restore her sex drive but could cause discontinuation symptoms; she could lower the dose of the antidepressant, which might provoke a relapse of depression; or we could try to counteract the side effects with another medication.
A temporary escape didn't appeal to Susan, so we decided on the third approach, an antidote. The question was, Which one? Serotonin-blocking drugs like Periactin, an antihistamine, treat sexual side effects, but they can also undo the drugs' antidepressant effects. I decided to prescribe Wellbutrin, a different class of antidepressant that has shown some ability to counteract sexual dysfunction caused by S.S.R.I.'s.
Little did I know.
Two weeks later, Susan called from her cellphone to say that the antidote was working. While shopping, she said, she spontaneously had an orgasm that had lasted on and off for nearly two hours . She was more delighted than alarmed, but I was stunned. I have had my share of therapeutic surprises, but this was hard to believe.
Was this a medical emergency or unrepeatable fluke that Susan needn't worry about? When I saw her the next day in my office, she was calm and somewhat amused by my concern. After all, since when is an orgasm a cause for alarm?
I was worried, though, that the addition of Wellbutrin had set off an episode of mania, an effect that antidepressants can have in up to 5 percent of patients. In that case, her prolonged orgasm might be a symptom of hypersexuality, common in mania. But Susan didn't seem either manic or depressed.
It seems that for her, the Wellbutrin just had an extreme sexually enhancing effect. Several colleagues told me about patients of theirs who had experienced heightened sexual desire on Wellbutrin, but none of the reports came close to Susan's. That Wellbutrin can enhance sexual pleasure isn't surprising: it increases the activity of dopamine, a key neurotransmitter in the brain's reward pathway. In fact, drugs of abuse, like cocaine, alcohol and opiates, release dopamine in this circuit - and so does sex.
A year has passed without a recurrence of this surprising side effect. But Susan is enjoying sex now - clearly more than she did before she became depressed. Because this was her first episode of major depression, the chance of a recurrence was only about 50 percent, so I suggested stopping the antidepressant. She liked that idea, but then paused and asked, "Do I have to stop the Wellbutrin, too?"
We both laughed.
