Redux relabeling notes higher risk - Interneuron Pharmaceuticals and distributor Wyeth-Ayerst agreed to put new labels on Redux, warning of risk of primary pulmonary hypertension - Updates - Brief Article

FDA Consumer, Nov, 1996

At FDA's request, the manufacturer and distributor of Redux (dexfenfluramine) have updated the weight-loss drug's labeling to inform doctors and patients about the increased risk of a rare, but serious and life-threatening, lung disorder - primary pulmonary hypertension, or PPH.

FDA made the request last August after evaluating the final report on the International Primary Pulmonary Hypertension Study. Preliminary evaluation of the study, before approval of Redux, found the PPH risk in users of appetite-suppressant drugs for three months or longer to be about nine times higher than in nonusers. The final report estimates the risk to be about 23 times higher.

Previous labeling reported PPH occurrence to be about 18 cases per million for adults using Redux three months or longer, compared to about 1 or 2 per million adults in the general population. Occurrence is now estimated at 23 to 46 cases per million patients per year.

Although the risk of PPH in patients taking appetite-suppressant drugs remains small, this is a serious disorder with a four-year death rate of 45 percent.

Redux treatment should be stopped if the patient develops unexplained symptoms, including breathing difficulty, chest pain, faintness, or swelling in the lower legs or ankles. Those taking Redux should call a doctor if they have any PPH symptoms or problems exercising. Any appetite-suppressant drug should be taken only under careful medical supervision.

Questions have been raised about studies showing long-term changes in the brains of animals. The relevance of these findings to humans is unknown.

The manufacturer of Redux, Interneuron Pharmaceuticals Inc. of Lexington, Mass., and the distributor, Wyeth-Ayerst of Philadelphia, sent letters to more than 300,000 health-care providers advising that the new findings reinforce the conclusion that Redux should not be used for "cosmetic" weight loss - that is, when the person's height-to-weight ratio does not provide a medical reason for weight loss. (See "New Weight-Loss Drug" in the Updates section of the July-August 1996 FDA Consumer.)

Wyeth-Ayerst has agreed to report cases of PPH to FDA within 15 days.

Health-care professionals should report adverse events to Wyeth-Ayerst by calling (1-800) 934-5556, or to the FDA MEDWATCH Program by calling (1-800) FDA-1088, or by mailing the report to MEDWATCH, HF-2, FDA, Rockville, MD 20857.

(For more about weight loss, see "Losing Weight Safely" in the January-February 1996 FDA Consumer.)