What is a common motor side effect associated with dopamine D2 antagonists used in antipsychotic medications?

What is a common motor side effect associated with dopamine D2 antagonists used in antipsychotic medications?

• A. Increased appetite.
• B. Extrapyramidal symptoms such as rigidity or tremor.
• C. Enhanced memory.
• D. Improved sense of taste.

Answer: (B)

Blocking dopamine D2 receptors in the brain’s motor pathways disrupts normal motor control, leading to extrapyramidal symptoms. These symptoms arise because the nigrostriatal pathway, which helps regulate movement, relies on dopamine signaling. When D2 receptors are blocked by antipsychotic drugs, this signaling is reduced, producing motor effects that resemble Parkinson’s disease—rigidity, tremor, slowed movement, and sometimes restlessness (akathisia). This motor side effect is classically associated with traditional, or typical, antipsychotics that strongly antagonize D2 receptors and is often dose-related. In contrast, many non-motor effects like changes in appetite, memory, or taste aren’t tied to this motor pathway, though some antipsychotics can still affect weight or cognition through other mechanisms. If extrapyramidal symptoms occur, clinicians may counter them with anticholinergic medications or switch to antipsychotics with less impact on the nigrostriatal pathway.

Blocking dopamine D2 receptors in the brain’s motor pathways disrupts normal motor control, leading to extrapyramidal symptoms. These symptoms arise because the nigrostriatal pathway, which helps regulate movement, relies on dopamine signaling. When D2 receptors are blocked by antipsychotic drugs, this signaling is reduced, producing motor effects that resemble Parkinson’s disease—rigidity, tremor, slowed movement, and sometimes restlessness (akathisia). This motor side effect is classically associated with traditional, or typical, antipsychotics that strongly antagonize D2 receptors and is often dose-related. In contrast, many non-motor effects like changes in appetite, memory, or taste aren’t tied to this motor pathway, though some antipsychotics can still affect weight or cognition through other mechanisms. If extrapyramidal symptoms occur, clinicians may counter them with anticholinergic medications or switch to antipsychotics with less impact on the nigrostriatal pathway.