Cholinergic rebound occurs when high-affinity cholinergic antagonist is replaced by an antipsychotic with no affinity for blocking cholinergic receptors.

• A. Cholinergic rebound
• B. Flu-like symptoms
• C. Dopaminergic rebound
• D. Acute withdrawal effects

Answer: (A)

Cholinergic rebound happens when the blockade of muscarinic receptors is reduced or removed. A high-affinity cholinergic antagonist blocks those receptors, dampening acetylcholine’s effects. If you switch to an antipsychotic that has little to no affinity for muscarinic receptors, the previously blocked acetylcholine activity becomes unopposed, leading to rebound cholinergic symptoms. In this scenario, the brain experiences an increase in muscarinic activity, producing symptoms such as increased secretions, GI motility, sweating, and other cholinergic effects.

That’s why the described situation fits cholinergic rebound best. The other options describe general withdrawal or other neurotransmitter rebound phenomena but do not specifically reflect the rise in muscarinic activity that occurs when a non-anticholinergic antipsychotic is started after a potent anticholinergic agent.