Why is clozapine unique among antipsychotics, and what monitoring is required?

• A. Exacerbates psychosis; monitoring liver enzymes only.
• B. Effective for treatment-resistant schizophrenia; requires regular CBC with ANC due to agranulocytosis risk.
• C. Causes no side effects; no monitoring required.
• D. Is first-line for all schizophrenia; monitoring cholesterol.

Answer: (B)

Clozapine stands out because it’s the only antipsychotic proven to work in treatment-resistant schizophrenia and it also helps reduce suicidality in this population. But its use comes with a serious safety concern: agranulocytosis, a dangerous drop in neutrophils that can lead to life-threatening infections. That risk is why regular blood monitoring is required—specifically a complete blood count with an absolute neutrophil count. If neutrophil levels fall too low, clozapine must be paused or stopped until counts recover. Because of this, patients on clozapine are usually enrolled in a monitoring program and have CBC with ANC checked on a strict schedule, especially in the early months of treatment. This combination of unique efficacy in difficult cases and the need for rigorous neutropenia monitoring is what makes clozapine distinct among antipsychotics.