Risperidone primarily works by blocking dopamine D2 and serotonin 5-HT2A receptors in the brain. This dual action is key to its effectiveness in treating schizophrenia’s positive symptoms, such as hallucinations and delusions. By antagonizing dopamine D2 receptors, risperidone reduces the excessive dopamine activity believed to contribute to these symptoms.
Serotonin’s Role in Risperidone’s Action
The serotonin 5-HT2A receptor antagonism is equally important. It counteracts some of the undesirable side effects associated with dopamine blockade, such as extrapyramidal symptoms (EPS), while potentially enhancing its impact on negative symptoms, like social withdrawal and flat affect. This balanced approach distinguishes risperidone from older antipsychotics that primarily target dopamine.
Other Receptor Interactions
Risperidone also interacts with other receptors, though to a lesser extent. These include alpha-1 adrenergic, histamine H1, and muscarinic receptors. These interactions can explain some of the side effects commonly observed, such as drowsiness, dizziness, and weight gain. Understanding these interactions helps clinicians manage potential adverse effects.
