Phentermine FAQs

Fen-Phen is the combination of Fenfluramine or Pondimin (the "Fen") and Phentermine (the "Phen"). Fenfluramine and Phentermine are prescription medications used as appetite suppressants for the short-term (a few weeks) management of obesity.

Phentermine received FDA approval in 1959 and Fenfluramine in 1973. Together, the two medications produced a powerful diet drug. The FDA had never approved the Fen-Phen combination, but once the agency has approved a drug, doctors may prescribe it at will.

Phentermine has also been used in combination with Dexfenfluramine ("Dexfen-Phen"). Dexfenfluramine (or Redux) was approved in 1996 for use as an appetite suppressant in the management of obesity.

In 1992, Dr. Michael Weintraub of the University of Rochester and several colleagues published a study showing Fen-Phen as far more effective than dieting or exercise in reducing the weight of the chronically obese. Initially, Fen-Phen seemed to be without immediate side effects.

Soon, Fen-Phen was on the market. In just a short time, Fen-Phen became a national sensation, with 6.6 million prescriptions in 1996.

Dexfen-Phen - The combination of Redux or Dexfenfluramine - a more refined compound that, like Fen-Phen, affects seratonin levels, but with fewer side effects than Fenfluramine - and Phentermine also became a sensation.

Unfortunately, neither combination was tested for safety... By the summer of 1997, the Food and Drug Administration (FDA) found 24 cases of heart-valve deterioration in women who had taken the Fen-Phen combination. Throughout the summer, the FDA received additional reports of heart disease, including reports from patients who had taken only Fenfluramine or Dexfenfluramine.

In September 1997, The FDA requested drug manufacturers to voluntarily withdraw Fenfluramine and Dexfenfluramine. The FDA also recommended that patients using either Fenfluramine or Dexfenfluramine stop doing so. To read the FDA statement regarding the withdrawals, please click here.

The FDA did NOT, however, request the withdrawal of the third drug involved in the cocktails, Phentermine.