On Sept. 15, 1997, Wyeth-Ayerst Laboratories and Interneuron Pharmaceuticals, manufacturers of the popular off-label obesity combination therapy known as fen-phen, agreed to a voluntary withdrawal.

The Food and Drug Administration (FDA) requested the withdrawal of the drugs fenfluramine, sold as Pondimin, and dexfenfluramine, sold as Redux. Wyeth-Ayerst Laboratories, the manufacturer of Pondimin and the distributor of Redux, agreed to recall the drugs immediately.

The FDA said those using the prescription drugs should stop doing so immediately. The agency’s action also prompted the French company that sells fenfluramine and dexfenfluramine abroad to withdraw the drugs worldwide.