Which antipsychotic is primarily used for treatment-resistant schizophrenia?

Clozapine is the antipsychotic primarily used for treatment-resistant schizophrenia due to its unique efficacy profile in patients who do not respond to other antipsychotic medications. It is the only medication approved for treatment-resistant schizophrenia and has been shown to significantly reduce symptoms in approximately one-third of patients who have not benefited from other treatments.

Clozapine's mechanism of action is thought to involve a combination of antagonism of dopamine and serotonin receptors, with a notable affinity for the D4 dopamine receptor and the 5-HT2A serotonin receptor. This broader spectrum of receptor activity contributes to its effectiveness in patients with complex and treatment-resistant cases of schizophrenia. Additionally, clozapine is associated with a reduction in the risk of suicide among patients with schizophrenia, which further supports its use in difficult cases.

Due to the risk of agranulocytosis, a potentially serious side effect that involves a dangerous drop in white blood cell count, patients on clozapine must be closely monitored with regular blood tests. This requirement underscores the importance of using clozapine in carefully selected patients who demonstrate treatment resistance, balancing its benefits against potential risks.

In contrast, other antipsychotics like risperidone, olanzap