Neuroleptic malignant syndrome is described as which of the following?

• A. NMS is acute onset due to D2 receptor antagonism and more common with high-potency FGAs.
• B. NMS is caused by GABA antagonism.
• C. NMS is chronic and unrelated to potency.
• D. NMS is caused by serotonin receptor agonism.

Answer: (A)

Neuroleptic malignant syndrome is an acute, life-threatening reaction caused by strong dopamine D2 receptor blockade from antipsychotic drugs. It tends to appear rapidly after starting or increasing the dose, and its classic features include fever, severe muscle rigidity, autonomic instability, and altered mental status. The risk is higher with high-potency typical antipsychotics because they produce more complete D2 blockade at standard doses, which drives the acute syndrome.

This isn’t caused by GABA antagonism, and it isn’t a chronic condition that develops over time. It also isn’t due to serotonin receptor agonism; that mechanism is associated with serotonin syndrome, which has a different clinical picture.