Mechanisms of appetite modulation by drugs.

The regulation of appetite is a complex process that we are just beginning to understand. It consists of both central and peripheral elements and involves the integration by the brain of a variety of signals from peripheral organs transmitted by neurotransmitters, peptides, hormones, and metabolites. All available anorectic drugs act by central mechanisms and have several disadvantages including limited effectiveness, side effects on the central nervous system, the development of tolerance, abuse potential, and rebound hyperphagia on discontinuance. Several appetite-modulating agents have been tested in animals that act by peripheral mechanisms and do not produce tolerance or rebound hyperphagia, which suggests that peripherally acting anorectic drugs may provide novel therapeutic approaches to disorders of appetite regulation in humans.