Worst Pills, Best Pills

An expert, independent second opinion on more than 1,800 prescription drugs, over-the-counter medications, and supplements

Drug Profile

Do NOT stop taking this or any drug without the advice of your physician. Some drugs can cause severe adverse effects when they are stopped suddenly.

Do Not Use [what does this mean?]
Generic drug name: benzphetamine (benz FET a meen)
Brand name(s): DIDREX
GENERIC: not available FAMILY: Diet Drugs
Find the drug label by searching at DailyMed.

Do Not Use [what does this mean?]
Generic drug name: diethylpropion (dye eth il PROE pee on)
Brand name(s): DURAD, TENUATE, TENUATE DOSPAN, TEPANIL
GENERIC: not available FAMILY: Diet Drugs
Find the drug label by searching at DailyMed.

Do Not Use [what does this mean?]
Generic drug name: phendimetrazine (fen dye MET ra zeen)
Brand name(s): BONTRIL PDM, PLEGINE
GENERIC: not available FAMILY: Diet Drugs
Find the drug label by searching at DailyMed.

Do Not Use [what does this mean?]
Generic drug name: phentermine (FEN ter meen)
Brand name(s): ADIPEX-P, ATTI PLEX P, FASTIN, IONAMIN, KRAFTOBESE, LOMAIRA, PANSHAPE M, PHENTERCOT, PHENTRIDE, PRO-FAST, RAPHTRE, SUPRAMINE, TARA-8, TERAMINE, TERMENE
GENERIC: not available FAMILY: Diet Drugs
Find the drug label by searching at DailyMed.

Alternative Treatment [top]

Lifestyle changes, diet, and exercise.

Facts About This Drug [top]

Benzphetamine (DIDREX), diethylpropion (TENUATE, TEPANIL), phendimetrazine (PLEGINE) and phentermine (ADIPEX-P, FASTIN) are grouped together because of their chemical and pharmacological similarities to amphetamine, the prototype of “speed”-like drugs. All four of these drugs carry similar information in their Food and Drug Administration- (FDA-) approved professional product labeling or package insert on the substantial toxicity and limited effect on weight of these drugs.[1],[2],[3],[4]

All...

Benzphetamine (DIDREX), diethylpropion (TENUATE, TEPANIL), phendimetrazine (PLEGINE) and phentermine (ADIPEX-P, FASTIN) are grouped together because of their chemical and pharmacological similarities to amphetamine, the prototype of “speed”-like drugs. All four of these drugs carry similar information in their Food and Drug Administration- (FDA-) approved professional product labeling or package insert on the substantial toxicity and limited effect on weight of these drugs.[1],[2],[3],[4]

All four of these drugs raise blood pressure and cause central nervous system stimulation, similar to amphetamine. They are all controlled substances; using them can lead to tolerance and a potential for dependence. The magnitude of weight loss with these drugs compared with a placebo is only a fraction of a pound per week.

These drugs are approved by the FDA only for a few weeks’ use in combination with a regimen of weight reduction based on caloric restriction. None of these drugs should be used in people with arteriosclerosis, cardiovascular disease, moderate or severe high blood pressure, overactive thyroid, glaucoma or agitated states, or in those taking other central nervous system stimulants or the monoamine oxidase inhibitor antidepressants.

Phentermine was the “phen” half of the once widely prescribed “fen-phen” diet drug combination. The “fen” portion of this combination, now banned, was fenfluramine (PONDIMIN). Fen-phen was one of the major driving forces behind the lucrative diet clinic industry of the early and mid-1990s. The economic boom for diet clinic doctors abruptly ended in September 1997 when phentermine and its close chemical cousin dexfenfluramine (REDUX) were removed from the market because of life-threatening adverse drug reactions.[5]

Phentermine was not removed from the market, but additional warnings were added to its professional product labeling about the development of heart valve damage and about a severe adverse reaction of the lungs known as primary pulmonary hypertension, and stating that the drug should be used alone and only for a short period of time.

No diet drug, including these four, has ever been shown to confer a health benefit in terms of reducing the serious complications associated with long-term obesity.

Regulatory issues surrounding these drugs

2010: In February 2010 the FDA issued an advisory warning on benzphetamine (DIDREX) highlighting information updates to the Warnings, Precautions and Adverse Reaction section of the drug product label. To see the detailed information go to http://www.fda.gov/Safety/MedWatch/SafetyInformation/ucm202912.htm[6]

last reviewed May 31, 2021