Anti-obesity drugs include all pharmacological treatments intended to reduce or control weight.
Because these drugs are intended to alter one of the fundamental processes of the human body, anti-obesity drugs are medically prescribed only in cases of morbid obesity, where weight loss is life-saving.
Anti-obesity drugs operate through one or more of the following mechanisms:
Suppression of the appetite.
Epilepsy medications and catecholamines and their derivatives (such as amphetamine-based drugs) are the main tools used for this.
Drugs blocking the cannabinoid receptors may be a future strategy for appetite suppression.
Increase of the body's metabolism.
Interference with the body's ability to absorb specific nutrients in food.
For example, Orlistat (also known as Xenical and Allī) blocks fat breakdown and thereby prevents fat absorption.
The OTC fiber supplements glucomannan and guar gum have been used for the purpose of inhibiting digestion and lowering caloric absorption
Anorectics (also known as anorexigenics) are primarily intended to suppress the appetite, but most of the drugs in this class also act as stimulants (dexedrine, e.g.), and patients have abused drugs "off label" to suppress appetite (e.g. digoxin).