When Was Phentermine Taken Off the Market?

Phentermine was not taken off the market. It remains available today as a prescription medication used for short-term weight management.

While phentermine was a component of the well-known weight-loss drug combination called "fen-phen," it was specifically the fenfluramine and dexfenfluramine components of this combination that were withdrawn due to safety concerns.

The Fen-Phen Controversy and Drug Withdrawals

The "fen-phen" combination, which typically included fenfluramine and phentermine, gained significant popularity in the 1990s as a treatment for obesity. However, serious health risks associated with the fenfluramine part of the combination eventually led to its removal from the market.

• Emerging Health Concerns: Reports began to surface linking the use of fen-phen and dexfenfluramine to severe medical conditions. These primary concerns included:
  • Valvular heart disease: Damage to the heart valves.
  • Pulmonary hypertension: A serious condition involving high blood pressure in the arteries of the lungs.
• FDA Action in 1997: After evaluating numerous reports of these adverse effects, particularly among women undergoing treatment, the U.S. Food and Drug Administration (FDA) formally requested the withdrawal of fenfluramine and dexfenfluramine from the market in September 1997.

Why Phentermine Remained Available

Unlike fenfluramine and dexfenfluramine, phentermine did not demonstrate the same severe cardiovascular or pulmonary side effects when used on its own. Consequently, it was not included in the FDA's withdrawal request and has continued to be an approved prescription medication.

It is crucial to differentiate between the combination drug "fen-phen" being discontinued due to the risks of fenfluramine, and phentermine continuing to be a recognized and prescribed treatment option for obesity when used under appropriate medical guidance.