Dopaminergic rebound occurs when a high D2 affinity drug is replaced with a low D2 affinity drug.

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

Answer: (B)

The concept hinges on how dopamine receptors are blocked by antipsychotic drugs. A high D2 affinity drug sits on the D2 receptors very strongly, producing substantial and sustained blockade. When you switch to a drug with lower D2 affinity, the degree of blockade diminishes, but endogenous dopamine is still being released. With fewer receptors blocked, more dopamine can stimulate the remaining available D2 receptors, leading to a surge or rebound of dopaminergic activity. This rebound can cause a temporary return or worsening of psychotic symptoms or other dopamine-related effects after the switch.

This phenomenon is distinct from cholinergic rebound or generic acute withdrawal symptoms, which aren’t driven by a change in D2 receptor blockade and dopaminergic signaling. In practice, to minimize this rebound, clinicians often use a cross-titration strategy to maintain some D2 blockade during the transition and monitor closely for symptom changes.