What is the most serious side effect associated with clozapine?

Clozapine is an atypical antipsychotic that is primarily used to treat treatment-resistant schizophrenia. One of its most significant and serious side effects is agranulocytosis, which is a potentially life-threatening decrease in the white blood cell count, specifically neutrophils. This side effect can increase the risk of infections and is the reason why patients on clozapine require regular monitoring of their complete blood counts (CBC) throughout treatment.

The occurrence of agranulocytosis can lead to severe complications, including febrile neutropenia, sepsis, and even death if not promptly recognized and managed. The risk of agranulocytosis is particularly concerning because it can occur early in treatment or after extended use, making vigilance necessary throughout the course of therapy.

While weight gain, diabetes mellitus, and QT-segment prolongation are also potential side effects associated with clozapine, they do not carry the same level of immediate risk to a patient's life as agranulocytosis does. Monitoring parameters and taking preventative measures for agranulocytosis are crucial in ensuring patient safety during clozapine therapy.