Olanzapine hydrochloride is a selective, orally active monoaminergic antagonist with high affinity binding to serotonin H1, 5HT2A/2C, 5HT3, 5HT6 ( K i =7, 4, 11, 57, and 5 nM, respectively), dopamine D1-4 ( K i =11 to 31 nM), muscarinic M1-5 ( K i =1.9-25 nM), and adrenergicα1 receptor ( K i =19nM). Olanzapine hydrochloride is an atypical antipsychotic.