News & Perspectives

New Findings, and New Warnings, about a Popular Pick-Me-Up

The bright yellow–flowered herb St. John’s wort has gained a reputation as a safe and effective alternative to Prozac for the treatment of mild to moderate depression. The herb’s reputation is bolstered by a spate of sound scientific studies, most recently a large trial from Germany that found it to be as beneficial, and far better tolerated, than the tricyclic antidepressant drug imipramine (British Medical Journal, 9/2/00).

However, several recent medical reports have raised flags about potentially dangerous interactions between St. John’s wort and some prescription drugs.

The problem seems to be that St. John’s wort can rev up the elimination of certain drugs from the body. As a result, the drug you take in the morning may not be effective by afternoon. Among the medications that may be affected are the heart drugs digoxin and warfarin, the HIV-fighter indinavir, and the organ transplant aid cyclosporine. There are even concerns that the herb may diminish the effectiveness of the contraceptive pill, though there have been no reported pregnancies in women who combine the two.

Proceed with Caution

If you’re taking St. John’s wort with prescription drugs, see your doctor; you may need to increase the dose of certain medications. But anything that a person ingests—grapefruit juice, foods, other medications—can alter the way the body absorbs and uses drugs. And drug interactions vary from person to person. Millions of people currently benefit from St. John’s wort, with no ill effects. It should be safe to continue taking it—provided you use common sense.

A Gentle Choice

Many studies confirm the benefits of the herb. Earlier reports from the University of Washington (Archives of Internal Medicine, 1/24/00) and Germany (British Medical Journal, 12/11/99) found it to be more effective than a placebo and nearly or more effective than tricyclic antidepressant drugs, such as imipramine.

How does St. John’s wort compare with the newer SSRI antidepressants, like Prozac, or to depression-fighting supplements like SAM-e? Unfortunately, studies are lacking.

"When we planned our study four years ago," says herbal researcher Dr. Karl Hillerof Germany, "Imipramine was considered the gold standard in antidepressants in Germany, so that’s what we compared it to."

A three-year, NIH-funded study comparing St. John’s wort and Zoloft is currently under way at Duke University. And further research is needed on herb-drug interactions and on herbal side effects. Still, many experts feel herbs in general are safer and gentler than most drugs.

Cautions: Always see a physician if you’re depressed. Tell your doctor of any herbs you are taking. Don’t combine St. John’s wort with other antidepressants, such as Prozac. And report any unusual symptoms that arise.

Suggested dose: 300 mg, three times a day, with meals. Some newer preparations allow twice-daily dosing: 450 mg twice a day. Because St. John’s wort needs to build up in your system to be effective, you may need to take the herb regularly for up to four weeks before you notice improvement.

Date Posted: 09/08/2000

Date Published: 09/07/2000
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