Phentermine is an appetite suppressant that is commonly prescribed and accounts for 50% of appetite suppressant prescriptions. Partly it is because Phentermine is significantly cheaper than any other FDA-approved diet drug such as Meridia and Xenical. The Food and Drug Administration (FDA) first approved Phentermine as an appetite suppressant, for the short-term treatment of obesity, in 1959. Phentermine resin United States, also became available in 1959 with Phentermine Hydrochloride following in the early 1970s

Presently Phentermine is available as a generic medication, known as phentermine, and is also sold in the US under the brand names - Ionamin® (Medeva Pharmaceuticals) and Adipex-P® (Gate Pharmaceuticals). It was sold previously under the name Fastin®, produced by King Pharmaceuticals for Smith-Kline Beecham. Smith-Kline Beecham removed Fastin from the marketplace in December 1998.

Phentermine being an older drug has no new efficacy trial documentation available. With one notable exception, several trials were conducted on a Phentermine / Fenfluramine combination treatment during the early to mid 1990s.

Passing Trends : FEN-PHEN (or Phen-Fen) and Dexfen-Phen 

Fen-Phen is a cocktail, of Fenfluramine (Pondimin - Fen) and Phentermine (Phen). Fenfluramine obtained FDA approval for short-term treatment of obesity in 1973. Jointly, Phentermine and Fenfluramine fashioned a powerful diet drug cocktail that the FDA has never approved. Usually once the FDA has approved a drug, doctors are allowed to prescribe it at will. Though the Fen - Phen cocktail was considered “off-label”.

In 1992 a study was published a citing Fen-Phen as a method more effective than dieting or exercise for weight reduction in the chronically obese. Unlike the earlier production of speed-laden drugs for dieting Fen-Phen seemed to be free from side effects. 1996 witnessed 6.6 million prescriptions of the Fen-Phen cocktail in the U.S.

Dexfen-Phen is the combination of Dexfenfluramine or Redux (Dexfen) and Phentermine (Phen). Dexfenfluramine was approved by the FDA in 1996 as an appetite suppressant for the maintenance and management of obesity. As with Fen-Phen; Dexfen-Phen, became a sensation overnight.

Neither of these combinations was ever tested for safety.

The Mayo Clinic had reported twenty four cases of valvular heart disease by the summer of 1997. In all cases the people had used the Fen-Phen cocktail. This unusual amount of cases of heart valve disease in the Fen-Phen users was suggestive of a correlation between use of Fen-Phen and heart valve disease.

The FDA released a Public Health Advisory to report findings from the Mayo Clinic on July 8, 1997. (also published in the August 28 issue of the New England Journal of Medicine). Click here to see the FDA Health Advisory, but continued to receive reports of heart disease, also from patients who had only taken Dexfenfluramine or Fenfluramine and not the cocktail.

Additional evaluations made on patients using either Fenfluramine or Dexfenfluramine, indicated that approximately 30% presented with abnormal heart valve results. This amount is far more than should be expected in any abnormal test results, and suggests that Fenfluramine and Dexfenfluramine were very likely the cause of the valvular heart disease and Primary Pulmonary Hypertension (PPH).

These findings were alarming and prompted the FDA to respond. In September 1997 the FDA requested that drug manufacturers voluntarily withdraw both these drugs. Simultaneously, it was recommended by the FDA that patients taking Fenfluramine or Dexfenfluramine should stop taking them. Please click here. For FDA September 1997 statement regarding this withdrawal.

However the FDA did not, request the withdrawal of Phentermine, the third drug mixed up with the cocktails.

PHEN-PRO

The most modern cocktail including Phentermine is "Phen-Pro" - the "Pro” for Prozac. The following antidepressants: Celexa ,Zoloft, Trazadone, Luvox, or Effexor may be used instead of Prozac. The use of antidepressant for the Phen-Pro cocktail is not related to depression. This cocktail has become effective as the effect of Phentermine, if used alone, becomes less over time. The Phen-Pro cocktail lets Phentermine  provide an enhanced result over longer periods of time. This cocktail does not seem to cause the same problems resulting from the use of Fen-Phen. The Phentermine / Prozac cocktail is also considered "off-label", and the FDA, does not approve its use.