What is a common side effect of the antipsychotic drug clozapine?

Clozapine is an atypical antipsychotic that is particularly effective in treatment-resistant schizophrenia. However, one of its most serious side effects is agranulocytosis, which is a potentially life-threatening reduction in the number of white blood cells (neutrophils) in the bloodstream. This condition increases the risk of infections and requires regular monitoring of blood cell counts during treatment.

Because of the risk of agranulocytosis associated with clozapine, patients are often required to have their absolute neutrophil count (ANC) monitored weekly for the first six months of treatment, and then every other week thereafter once the safety of the treatment is established. This monitoring is a critical safety measure that sets clozapine apart from many other antipsychotics, which do not carry the same level of risk in this regard.

While other side effects such as weight gain, dry mouth, and drowsiness can occur with antipsychotic medications, agranulocytosis is particularly significant for clozapine and is a key reason healthcare providers carefully consider its use.