NEW YORK, May 04 (Reuters Health) - The herbal St. John's wort is an herbal remedy sold as an over-the-counter treatment for depression--and the legitimacy of that claim has received a boost from a professional medical group.

      In its new guidelines for antidepressant prescriptions, the American College of Physicians-American Society of Internal Medicine (ACP-ASIM) states that newer and traditional drugs are equally effective for many depression sufferers. It also states St. John's wort may be effective against "mild" depression, at least in the short term.

      However, Dr. Herbert H. Waxman told Reuters Health in an interview that the buyer must beware. Since St. John's wort is not regulated as a drug, the array of preparations at health food stores contains varying amounts of the active ingredient. In addition, he said, St. John's wort is known to interact with prescription drugs, including blood thinners and birth control pills , as well as substantially reduce the effectiveness of the HIV-fighting drug, indinavir. The ACP-ASIM published its guidelines in the May 2nd issue of the Annals of Internal Medicine.

      Despite the caveats, St. John's wort does have scientific evidence supporting its use as a self-prescribed antidepressant, according to Waxman, the senior vice-president for education for the ACP-ASIM. In a review of studies on the herb, an ACP-ASIM team found that across 14 trials, 62% of depression patients given St. John's wort reported improved symptoms compared with 38% taking an inactive placebo pill. Dr. John W. Williams, Jr., of the University of Texas Health Science Center at San Antonio, led the review.

      The same review also showed that widely used prescription antidepressants, both older and newer, equal each other in their effectiveness. Older drug classes include tricyclic antidepressants, and newer ones include selective serotonin reuptake inhibitors (SSRIs), a class of drug that includes Prozac and Zoloft. Across 150 studies comparing older and newer antidepressants, 54% of patients on either group of drugs reported symptom improvement.

      Given that well-designed studies consistently show that these drugs work, Waxman said, most doctors will naturally promote them over the unregulated, less-studied St. John's wort. "But in some circumstances," he added, "patients might have strong preferences, and doctors may want to consider St. John's wort."

      Deciding among the various prescription drugs, said Waxman, "comes down to deciding which side effects you can tolerate."

      In the ACP-ASIM review, the only significant differences between older and newer antidepressants were their side effects. For example, compared with tricyclics, SSRIs are more likely to cause diarrhea, nausea, headache and insomnia. Tricyclics, on the other hand, carried greater risk for blurred vision, constipation, dizziness, dry mouth and tremors.

      The review also revealed that there has been little study of the drugs in teenagers and in adults with other chronic medical conditions such as heart disease.

      According to Waxman, mildly depressed people who opt for self-medicating with St. John's wort should consult their doctors. "Even though a patient doesn't need my permission to take it," he said, "I'd like to know that it's entered their medical lives."     

      SOURCE: Annals of Internal Medicine 2000;132:743-756.