Which antipsychotic requires regular blood monitoring due to agranulocytosis risk?

• A. Quetiapine
• B. Clozapine
• C. Aripiprazole
• D. Olanzapine

Answer: (B)

A key safety concern here is a drug’s potential to cause agranulocytosis, a dangerous drop in neutrophils that can leave the body vulnerable to severe infections. Among common antipsychotics, one stands out for this risk and for requiring ongoing blood monitoring: clozapine. Because agranulocytosis can develop abruptly and be life-threatening, clozapine is paired with a strict hematologic monitoring program. This usually means checking the absolute neutrophil count regularly from the start of treatment and continuing with periodic checks to ensure counts remain in a safe range; if neutrophil counts fall too low, clozapine must be stopped to prevent serious infection.

The other antipsychotics listed do not carry the same mandated routine blood monitoring for agranulocytosis. They can have other important side effects—like metabolic changes with olanzapine or weight gain and sedation with quetiapine—but they do not require the same regular ANC surveillance for agranulocytosis.