Combining drugs with sex can be a prescription for frustration. From oral contraceptives to antidepressants and over-the-counter antihistamines, dozens of medicines commonly used by midlife women can inhibit desire, slow down sexual response or interfere with orgasms. As one disgruntled 40-year-old Paxil-taker put it, “What’s the point of having sex if you can’t have an orgasm? It’s like going on a trip and never arriving at the destination.”

Yet sexual side effects are rarely discussed when a physician recommends a course of treatment. For one thing, doctors and patients are notorious for clamming up about sex. What’s more, the physician may not even know that a specific drug can constitute a chemically induced cold shower. “These connections are barely touched on in medical school,” notes Anita Clayton, MD, professor of psychiatry and neurobehavioral sciences at the University of Virginia in Charlottesville.

Even popular over-the-counter drugs can cause trouble in the bedroom. Consider antihistamines — such as Benadryl, Claritin and Zyrtec — which are commonly used for allergy relief. “Women take them from the time leaves appear in the spring until they drop in the fall, without recognizing that the drugs can inhibit orgasms,” says Judith Seifer, PhD, a professor at the Institute for Human Sexuality and former president of the American Association of Sexuality Educators, Counselors and Therapists. The problem: “Antihistamines can act as a muscle relaxant, and you need a certain amount of muscle tension to build to the crescendo of orgasm.”

Some case reports in medical journals have also suggested that regular use of nonsteroidal anti-inflammatory medications (NSAIDs) — a category that includes Advil, Aleve and Motrin — might reduce lubrication, desire and arousal. Scientists are not sure why these over-the-counter drugs might cause these unwelcome reactions.

Sexual side effects are especially common with two types of medications that are being prescribed more frequently for midlife women.

Birth Control Pills
Oral contraceptives are showing up more often in the medicine chests of perimenopausal women — not only to prevent pregnancy but also to quell migraines, heavy bleeding due to fibroids, and hassles like hot flashes and night sweats. Unfortunately, the Pill can also squash desire, possibly for a long time.

Here’s how it happens: the Pill gets processed through the liver, where it increases levels of a protein called sex hormone-binding globulin (SHBG). This affects your sexual appetite because the SHBG binds with testosterone, the primary libido hormone, making it less available to the body — which can leave you less interested in sex. This can occur in any woman who’s on the Pill, but midlife women are more affected because they’re already experiencing hormonal changes.

Even if you go off the Pill, the libido-reducing levels of SHBG remain in your body for at least several months, according to new research from Boston University. Some doctors believe the effect may last for years, though there is no firm data. “Women who started on birth control pills when they were relatively young and stayed on them for several years seem most likely to be affected,” Clayton says.

Mood Boosters

The run-up to menopause is the time of life when women are likeliest to develop depression serious enough to require treatment — which often takes the form of antidepressants, the most bothersome of all sex-dampeners. Particularly potent are SSRIs (selective serotonin reuptake inhibitors), a category that includes the widely prescribed Prozac, Zoloft and Paxil. SSRIs counter depression by making the neurotransmitter serotonin more available in the brain. “Unfortunately, too much serotonin can inhibit orgasm and sexual interest,” says Richard Balon, MD, a professor of psychiatry at Wayne State University School of Medicine, in Detroit.

Probably 40 to 50 percent of women on SSRIs have sexual side effects, Balon estimates, and their ranks are likely to grow because many women over 40 are switching from treating hot fl ashes with hormones to relying on antidepressants, especially Paxil, Zoloft and Effexor (an SSRI relative).