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5-HTP supplements not always 'safer'. (Contaminant In L-Tryptophan Alternative).

SOUTHAMPTON, BERMUDA -- Some commercially available formulations of a popular dietary supplement 5-HTP, marketed as a "safer alternative" to L-tryptophan, contain the same contaminant that was responsible for more than 1,500 cases of eosinophilia-myalgia syndrome and at least 38 deaths associated with L-tryptophan use in 1989.

Patients who take 5-HTP (5-hydroxytryptophan) as an antidepressant, as a sleep aid, or for weight loss or other complaints may be at risk for developing the syndrome. In fact, 10 cases have been reported worldwide, Dr. Andrew L. Stoll said at a seminar on treating mood and anxiety disorders.

Some manufacturers test their products for the presence of the contaminant, known as "peak X" based on gas chromatography findings. Patients can call the manufacturer to ask if the product has been tested, said Dr. Stoll, director of the psychopharmacology research laboratory, McLean Hospital and Harvard Medical School, Boston. "I would only use 5-HTP from companies who confirm that their products are peak X-free," he told this newspaper.

Patients also need to be educated to watch for symptoms of eosinophilia-myalgia syndrome such as muscle pain or weakness, headache, and vomiting, Dr. Stoll said at the seminar sponsored by Harvard Medical School.

Patients also need to use caution if they are already taking a selective serotonin reuptake inhibitor; inexplicable worsening of mood has been reported in normal controls given 5-HTP in conjunction with an SSRI, he said.

The Food and Drug Administration issued a "talk paper" on 5-HTP in 1998, confirming that peak X had been identified in some products. Although the agency has not taken any action to remove the supplement from the market, it has stated that "vigilance is warranted."

Much of the peak X-contaminated L-tryptophan implicated in the 1989 outbreak ultimately was traced to a single Japanese manufacturer, Showa Denko.

L-tryptophan was pulled from the U.S. market in 1990, but remains available by prescription in Canada.

The rationale for using L-tryptophan and 5-HTP for depression is that 5-HTP is an immediate precursor of the neurotransmitter serotonin. L-tryptophan is metabolized to 5-HTP in the body.

Many studies have investigated the safety and efficacy of using these products to treat depression, but most have been flawed. A systematic review suggested that L-tryptophan and 5-HTP may be more effective than placebo, but noted "the evidence was of insufficient quality to be conclusive" (Cochrane Database Syst. Rev. [1]:CD0003198, 2002).

The starting dose is 300 mg twice daily; this can be increased to 300 mg three times per day, Dr. Stoll said.

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Author:Walsh, Nancy
Publication:Family Practice News
Geographic Code:5BERM
Date:Oct 1, 2002
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