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Medication in the Treatment of Obesity (cont.)

What Obesity Medications Should I Avoid?

Some medications are not recommended for weight loss because of safety concerns. Some are no longer available in the United States. Avoid them. Be sure to check any weight-loss products you acquire without a prescription, such as through mail-order pharmacies, to make sure they do not contain any of these products.


Two drugs known as fenfluramine (Pondimin) and dexfenfluramine (Redux) affect serotonin levels in the brain.

  • These drugs, which are closely related to each other, were used in drug combinations that became very popular in the 1990s for treatment of obesity.
  • The combination was commonly referred to as fen-phen.
  • These drugs were withdrawn from the market in 1997 after they were linked to heart-valve problems and primary pulmonary hypertension. Pulmonary hypertension affects the blood vessels in the lungs and is debilitating and often fatal.

Ephedrine (ephedra, ma-huang)

A ruling by the U.S. Food and Drug Administration (FDA) on Apr. 12, 2004, prohibits dietary supplements containing ephedrine alkaloids (ephedra).

Ephedra, also called ma-huang, is a naturally occurring substance derived from plants. Its principal active ingredient is ephedrine, which, when chemically synthesized, is regulated as a drug. In recent years, ephedra products have been extensively promoted to aid weight loss, enhance sports performance, and increase energy. However, the FDA has determined that ephedra presents an unreasonable risk of illness or injury. Ephedrine has been linked to significant adverse health effects, including high blood pressure, irregular heartbeat, heart attack, stroke, and death.


Phenylpropanolamine (PPA) is a stimulant that is closely related to ephedrine. PPA was previously an ingredient in appetite suppressants as well as over-the-counter cough and cold remedies.

  • The FDA has issued a warning regarding PPA use. As a result, manufacturers removed products containing PPA from the market in October 2000.
  • Studies have suggested that this product is associated with an increased risk of hemorrhagic (bleeding) stroke in women.

Medically reviewed by John A. Daller, MD; American Board of Surgery with subspecialty certification in surgical critical care


Allison, D.B., et al. "Controlled-release phentermine/topiramate in severely obese adults: a randomized controlled trial (EQUIP)." Obesity. 20.2 Feb. 2012: 330-42. Epub 2011 Nov3.

Fidler, M.C., et al. "A one-year randomized trial of lorcaserin for weight loss in obese and overweight adults: the BLOSSOM trial." J Clin Endocrinol Metab. 96.10 Oct. 2011: 3067-3077. Epub 2011 Jul27.

Gadde, K.M., et al. "Effects of low-dose, controlled-release, phentermine plus topiramate combination on weight and associated comorbidities in overweight and obese adults (CONQUER): a randomized, placebo-controlled, phase 3 trial." Lancet. 377.9774 Apr. 16, 2011: 1341-1352. Epub2011 Apr8.

Medically Reviewed by a Doctor on 11/22/2016
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