Olanzapine is an atypical (second-generation) antipsychotic that exerts its action primarily on dopamine and serotonin receptors. It works on dopamine D2 receptors in the mesolimbic pathway as an antagonist, blocking dopamine from potential action at the post-synaptic receptor. Olanzapine binds loosely to the receptor and dissociates easily, allowing for normal dopamine neurotransmission.The effect on the D2 receptors leads to a decrease in positive symptoms in patients, including hallucinations, delusions, and disorganized speech, thought, and behavior. Olanzapine works similarly on serotonin 5HT2A receptors in the frontal cortex as an antagonist. The effect of olanzapine on serotonin decreases negative symptoms, including anhedonia, flat affect, alogia, avolition, and poor attention.

Olanzapine Serotonin Antagonist Pathway References