Diethylpropion is a sympathomimetic stimulant drug marketed as an appetite suppressant. Chemically, it is the N,N-diethyl analog of cathinone. Its mechanism of action is similar to other appetite suppressants such as sibutramine, phentermine and dextroamphetamine. Diethylpropion is an amphetamine that stimulates neurons to release or maintain high levels of a particular group of neurotransmitters known as catecholamines; these include dopamine and norepinephrine. High levels of these catecholamines tend to suppress hunger signals and appetite. Diethylpropion (through catecholamine elevation) may also indirectly affect leptin levels in the brain. It is theorized that diethylpropion can raise levels of leptin which signal satiety. It is also theorized that increased levels of the catecholamines are partially responsible for halting another chemical messenger known as neuropeptide Y. This peptide initiates eating, decreases energy expenditure, and increases fat storage. It is used in the management of exogenous obesity as a short-term adjunct (a few weeks) in a regimen of weight reduction based on caloric restriction.

Subitramine is a potent inhibitor of monoamines (serotonin, dopamine, noradrenaline) reuptake that was approved by FDA for the treatmen of obesity. Sibutramine is metabolized to metabolites M1 and M2 which are more active toward the monoamine transporters.The drug was withdrawn from the market because of clinical trial data indicating an increased risk of heart attack and stroke. It was sold under a variety of brand names including Reductil, Meridia and Sibutrex.

Rimonabant (also known as SR141716; trade names Acomplia, Zimulti) was an anorectic antiobesity drug that was first approved in Europe in 2006 but was withdrawn worldwide in 2008 due to serious psychiatric side effects. Rimonabant is an inverse agonist for the cannabinoid receptor CB1 and was the first drug approved in that class. There is considerable evidence that the endocannabinoid (endogenous cannabinoid) system plays a significant role in appetitive drive and associated behaviors. It is, therefore, reasonable to hypothesize that the attenuation of the activity of this system would have therapeutic benefit in treating disorders that might have a component of excess appetitive drive or over-activity of the endocannabinoid system, such as obesity, ethanol and other drug abuse, and a variety of central nervous system and other disorders. Data from clinical trials submitted to regulatory authorities showed that rimonabant caused depressive disorders or mood alterations in up to 10% of subjects and suicidal ideation in around 1%, and in Europe, it was contraindicated for people with any psychiatric disorder, including depressed or suicidal people. Additionally, nausea and upper respiratory tract infections were very common (occurring in more than 10% of people) adverse effects; common adverse effects (occurring in between 1% and 10% of people) included gastroenteritis, anxiety, irritability, insomnia and other sleep disorders, hot flushes, diarrhea, vomiting, dry or itchy skin, tendonitis, muscle cramps and spasms, fatigue, flu-like symptoms, and increased risk of falling.

Dexfenfluramine, also marketed under the name Redux, is a serotoninergic anorectic drug. Dexfenfluramine, the dextrorotatory isomer of fenfluramine, is indicated for use in the management of obesity in patients with a body mass index of > or = 30 kg/m2, or > or = 27 kg/m2 in the presence of other risk factors. Unlike fenfluramine, dexfenfluramine is a pure serotonin agonist. Dexfenfluramine increases serotonergic activity by stimulating serotonin (5-hydroxytryptamine; 5-HT) release into brain synapses, inhibiting its reuptake into presynaptic neurons and by directly stimulating postsynaptic serotonin receptors. Dexfenfluramine reduces blood pressure, percent glycosylated hemoglobin, and concentrations of blood glucose and blood lipids, but these benefits may be indirect. Dexfenfluramine may also be of some value in controlling eating habits in diabetic patients, preventing weight gain after smoking cessation, and treating bulimia, seasonal affective disorder, neuroleptic-induced obesity, and premenstrual syndrome. Dexfenfluramine's most frequent adverse effects are insomnia, diarrhea, and headache; it has also been associated with primary pulmonary hypertension. The drug should not be combined with other serotonergic agonists because of the risk of serotonin syndrome. The recommended dosage is 15 mg twice daily. Dexfenfluramine is effective in the treatment of obesity in selected patients. Because its efficacy is lost after six months of continuous treatment, it should be viewed primarily as an adjunct to diet and exercise. Dexfenfluramine was approved by the FDA in 1996 and has been widely used for the treatment of obesity. However, Dexfenfluramine was removed from the U.S. market in 1997 following reports of valvular heart disease and pulmonary hypertension.

Mefenorex or (+/-)N-(3-chloropropyl)-1-methyl-2-phenylethylamine is an N-alkylated analogue of amphetamine. The therapeutic efficacy of mefenorex as an adjunctive support in the treatment of obesity for limited periods of time, as well as its ability to be well tolerated, has been amply demonstrated. Mefenorex is considered to be racemic mixture, no available data regarding enantiospecific pharmacological activity of the compound.