Which medication is most commonly associated with agranulocytosis?

Clozapine is the medication most commonly associated with agranulocytosis, a potentially severe side effect characterized by a dangerously low level of neutrophils, a type of white blood cell essential for fighting off infections. This risk is particularly significant with clozapine due to its unique pharmacological profile; it is an atypical antipsychotic primarily used in treatment-resistant schizophrenia.

Due to the risk of agranulocytosis, patients on clozapine require regular monitoring of their white blood cell counts, specifically the absolute neutrophil count (ANC). This monitoring is crucial because if agranulocytosis develops, it can lead to serious complications, including life-threatening infections.

Other atypical antipsychotics such as risperidone, olanzapine, and quetiapine do carry some risk for various side effects, including metabolic effects and sedation, but they are not as strongly associated with agranulocytosis as clozapine. This differentiation in risk is why clozapine is notably guided by specific management protocols that include regular blood testing to ensure patient safety.