Rebound Effect
An exaggerated return or worsening of symptoms when a drug is discontinued, often exceeding the original pre-treatment severity. Rebound effects can occur when the body has adapted to drug presence through receptor upregulation or other compensatory mechanisms.
Technical Context
Rebound occurs because the body adapts to the drug's presence through compensatory mechanisms (receptor upregulation, counter-regulatory pathway activation, altered set points). Upon discontinuation, these compensatory changes persist temporarily while the drug effect disappears, causing symptoms that exceed pre-treatment levels. For peptide drugs: GLP-1 RA discontinuation is followed by rapid appetite return and weight regain (the hypothalamic appetite circuits re-emerge from drug suppression), GnRH agonist discontinuation restores gonadotropin pulsatility and sex steroid production (gradual recovery over weeks-months, exploited in fertility protocols where post-flare recovery produces ovulation), and somatostatin analogue discontinuation may cause temporary GH/hormone rebound. Gradual dose tapering can attenuate rebound effects for some drugs, though this is not standard practice for all peptide drug classes.