Phentermine suppresses the appetite. For several years in the 1990s, it was part of a drug cocktail referred to as Fen-Phen that many found effective for weight loss. However, controversy and U.S. Food and Drug Administration recall followed when Fen-Phen users started developing heart problems. Despite this, phentermine is still legally available for purchase today; fenfluramine and dexfenfluramine -- the "Fen" in Fen-Phen -- are not.
Fen-Phen
Phentermine and fenfluramine combined to become Fen-Phen in the late 1970s. It was the brainchild of Dr. Michael Weintraub, then a researcher at the University of Rochester. The four-year study he undertook on the effectiveness of the drugs proved quite successful, with the average patient shedding 30 lbs. unwanted weight. Results were published in the 1992 journal "Clinical Pharmacology and Therapeutics."
Controversy
Although no side effects manifested during the Fen-Phen clinical study, the FDA noted that dexfenfluramine -- a stronger version of fenfluramine that drug manufacturers intended to market for this diet drug combination -- may cause pulmonary hypertension. The drug found approval in 1996 in spite of potential health problems. Several months later, two dozen women were reported to have serious heart valve problems due to taking Fen-Phen, specifically from fenfluramine and dexfenfluramine. Several months after that, a study of 291 Fen-Phen users revealed that two-thirds of them had developed this heart valve problem, and the FDA withdrew fenfluramine and dexfenfluramine from the market.
Phentermine Usage and Dosage
Your physician may prescribe phentermine to help you lose weight, although many don't consider it particularly effective. It's meant for short-term use only -- three to six weeks -- for obese people. You may buy this drug as tablets and capsules, and you should take it exactly as your physician instructs. The typical regimen includes taking one dose of phentermine when you wake up in the morning, although some physicians recommend taking it three times daily 30 minutes before eating.
Phentermine Side Effects
In spite of being part of a drug cocktail that caused heart valve deterioration, taking phentermine for weight loss doesn't damage your heart when used as directed. It can, however, cause side effects. Less serious complications include dry mouth, vomiting, diarrhea or constipation and the presence of an unpleasant taste in your mouth. Potentially dangerous side effects include elevated blood pressure, dizziness, shortness of breath, tremors, heart palpitations and swelling in your lower extremities. Contact your physician immediately if you experience any of these side effects.
References
- PubMed Health; Phentermine; Jan. 1, 2011
- U.S. Food and Drug Administration; FDA Announces Withdrawal Fenfluramine and Dexfenfluramine (Fen-Phen); Sept. 15, 1997
- "The New York Times"; How Fen-Phen, A Diet `Miracle,' Rose and Fell; Gina Kolata; Sept. 23, 1997
- Go Ask Alice!; Fen-Phen For Weight Loss; Sept. 13, 1996
- Drugs.com; Phentermine; January 2011
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