clozapine + olanzapine + risperidone

This is a combination of three atypical (second-generation) antipsychotic drugs—clozapine, olanzapine, and risperidone. Each drug acts primarily as an antagonist at dopamine D2 receptors and various serotonin receptors, but with distinct receptor binding profiles that contribute to their efficacy and side effect differences. Clozapine is notable for its superior efficacy in treatment-resistant schizophrenia but carries risks such as agranulocytosis and significant weight gain. Olanzapine is effective for both positive and negative symptoms of schizophrenia but also has a high risk of metabolic side effects. Risperidone is effective for a range of psychotic disorders with relatively higher rates of extrapyramidal symptoms compared to the other two agents. While all three are approved individually for the treatment of schizophrenia and related disorders, there is no established fixed-dose combination product containing all three; however, combinations may be used off-label in cases where monotherapy or dual therapy fails to achieve adequate symptom control in treatment-resistant patients[1][2][3][4][5]. The use of multiple antipsychotics increases the risk profile (including additive side effects), so such regimens are generally reserved for severe cases under close clinical supervision.