This article is from the Depression FAQ, by Cynthia Frazier with numerous contributions by others.
Both lowered sexual desire and difficulties having an orgasm, in both men and women, are particularly a problem with the selective serotonin re-uptake inhibitors (Prozac, Zoloft, Paxil and Luvox), and the monoamine oxidase inhibitors (Nardil and Parnate). There is no treatment for decreased sexual interest except lowering the dose or switching to a drug that does not have sexual side effects such as bupropion (Wellbutrin). Difficulty having orgasms may be treated by a number of medications. Among those medications are: Periactin, Urecholine, and Symmetrel. None of these are over-the-counter drugs and they must be prescribed by a physician. Unfortunately, many psychiatrists are not familiar with using these medications to treat the sexual side-effects of antidepressants.