What is a common extrapyramidal side effect of dopamine antagonists used as antiemetics, and how should it be managed?

What is a common extrapyramidal side effect of dopamine antagonists used as antiemetics, and how should it be managed?

• A. Hypertension; administer diuretic
• B. Rash; stop medication
• C. Acute dystonia, akathisia; administer anticholinergic or benzodiazepine as prescribed; monitor for restlessness
• D. Tachycardia; administer beta-blocker

Answer: (C)

Dopamine antagonists used as antiemetics can cause extrapyramidal symptoms because blocking D2 receptors in the nigrostriatal pathway disrupts normal movement control. The most common early effects you’ll see are acute dystonia (sudden, painful muscle contractions) and akathisia (a subjective sense of inner restlessness). Management targets restoring the balance in the motor circuits: give an anticholinergic agent such as benztropine or diphenhydramine, which counteracts the acetylcholine-dopamine imbalance, or a benzodiazepine to reduce anxiety and agitation. After treating, monitor the patient for continued restlessness or new movement symptoms, adjusting therapy as needed. These EPS are distinct from non-movement side effects like hypertension, rash, or tachycardia, which are not the classic extrapyramidal reactions associated with these drugs.

Dopamine antagonists used as antiemetics can cause extrapyramidal symptoms because blocking D2 receptors in the nigrostriatal pathway disrupts normal movement control. The most common early effects you’ll see are acute dystonia (sudden, painful muscle contractions) and akathisia (a subjective sense of inner restlessness).

Management targets restoring the balance in the motor circuits: give an anticholinergic agent such as benztropine or diphenhydramine, which counteracts the acetylcholine-dopamine imbalance, or a benzodiazepine to reduce anxiety and agitation. After treating, monitor the patient for continued restlessness or new movement symptoms, adjusting therapy as needed.

These EPS are distinct from non-movement side effects like hypertension, rash, or tachycardia, which are not the classic extrapyramidal reactions associated with these drugs.