Which condition is classified as an extrapyramidal side effect of antipsychotic therapy?

Which condition is classified as an extrapyramidal side effect of antipsychotic therapy?

• A. Acute dystonic reaction
• B. Hypertension
• C. Hyponatremia
• D. Dehydration

Answer: (A)

Extrapyramidal side effects arise from dopamine blockade in the basal ganglia, causing movement disorders. An acute dystonic reaction is a rapid, involuntary, sustained muscle contraction that can cause twisting or abnormal postures—often of the neck, face, or eyes—and typically appears within hours to days of starting or increasing antipsychotic therapy. This is a classic EPS because it directly reflects the imbalance between dopamine and acetylcholine in the nigrostriatal pathway, and it’s treated quickly with anticholinergic medications like benztropine or diphenhydramine to restore balance. The other options are not movement-related side effects of antipsychotics; hypertension, hyponatremia, and dehydration are distinct systemic issues and do not represent extrapyramidal effects.

Extrapyramidal side effects arise from dopamine blockade in the basal ganglia, causing movement disorders. An acute dystonic reaction is a rapid, involuntary, sustained muscle contraction that can cause twisting or abnormal postures—often of the neck, face, or eyes—and typically appears within hours to days of starting or increasing antipsychotic therapy. This is a classic EPS because it directly reflects the imbalance between dopamine and acetylcholine in the nigrostriatal pathway, and it’s treated quickly with anticholinergic medications like benztropine or diphenhydramine to restore balance. The other options are not movement-related side effects of antipsychotics; hypertension, hyponatremia, and dehydration are distinct systemic issues and do not represent extrapyramidal effects.