Important Timeline on the Weight Loss Drug Phentermine

Phentermine has been among the most prescribed and used weight loss drugs since late 1950s. After so many decades, the market has not yet invented the same weight loss drug that is as effective yet as controversial as the history of phentermine.

Early 1950s – The Introduction

It was in the early 1950s when phentermine was introduced as a highly effective weight loss drug and anti-obesity drug. It’s actually the first drug in the USA that claimed to reduce appetite by making the person feel fuller, thus lead to eating reduction. Phentermine started to dominate the American market for weight loss diet pills since its introduction. Studies suggest that it could have taken as high as 50% of all the diet pill sales back then.

1959 – The FDA Approval and Phentermine Resin

Finally, Food and Drugs Administration approved the use of phentermine as a short-term treatment for obesity. Also in the same year when Phentermine resin was developed. Being a short-term medication, phentermine can only be used up to 90 days or 12 weeks. It’s because phentermine is like an amphetamine suppressant drug that can be highly addictive. It also poses adverse side effects like higher blood pressure, over stimulation, dryness of mouth, and urticaria. The drug may also become less effective when used for prolonged period.

Early 1970s – Phentermine Hydrochloride

Combining hydrochloride to phenyl-tertiary-butylamine has resulted to this weight loss pill. The effect of this combination was studied and has proven to give better weight loss effects. But then again, this must only be used for a short-term medication and like the generic phentermine, also pose serious side effects.

1984 – The Revelation of Fen-Phen Clinical Trial

Michael Weintraub, MD and the collaborators from University of Rochester Medical Center revealed in their 1984 report that using phentermine and fenfluramine together is greatly more effective than using phentermine or fenfluramine alone. Like the phentermine, fenfluramine is an appetite suppressant drug. It works by increasing the neurotransmitter serotonin level, which leads to feeling of fullness and reduced eating.

Besides better effect, the authors also discovered that the Fen-Phen combination reduces the immediate side effects while providing better control on the appetite as compared to using either of these two alone. Because of this study, Fen-Phen became an instant hit in the American market.

Important Time Line on the weight loss drug phentermine

1992 – Results of Further Study

The same group of professionals continued to study the result of Fen-Phen when used for longer periods in their 3-year study. The result? They found out that using Fen-Phen is more effective when used for prolonged period, especially if the purpose is maintaining the significant weight loss. However, the study also revealed that stopping the Fen-Phen medication will result to regaining of weight even despite continuing other supportive weight loss treatments.

Despite this, the market still has high hopes on Fen-Phen. It became one of the best-selling weight loss drugs. In 1996 alone, there are about 6.6 million of prescriptions for Fen-Phen in the United States alones.

1997 – The Fall of Fen-Phen

Mayo Clinic reported about the 24 cases of heart valve disorder of patients who have been taking the Fen-Phen combination. More patients showed the same symptoms and all of them were using the Fen-Phen combination. The rare scenario suggests that Fen-Phen must have caused the disease. A study conducted in the same year revealed that almost 30% of those who were taking Fen-Phen have abnormal heart valves. On the same year, FDA issued an advisory regarding the report from Mayo Clinic and requested to stop distributing the combi-drugs.

Phentermine Today

The pulling out of Fen-Phen never ended the history of phentermine. Both the generic phentermine and branded phentermine are still among the most prescribed weight loss drugs. This long history of phentermine has already proven that it’s a survivor despite the many other weight loss drugs in the market simply because it is safe and effective. But the most interesting of all is the availability of herbal phentermine, which compared to any generic or branded Phentermine is safer yet as effective.