8-hydroxy Loxapine (8-OH loxapine) is a metabolite formed when loxapine , an atypical antipsychotic, is metabolized by the cytochrome P450 isoform CYP1A2. Loxapine displays high affinity for histamine, serotonin (5-HT), dopamine, and α1-adrenergic receptors (Ki values = 7, 7.7, 9.5, 12, and 31 nM for H1, 5-HT2A, 5-HT2C, D2, and α1A-adrenergic receptors, respectively). It reduces agitation associated with schizophrenia or bipolar disorder. 8-OH Loxapine is considered inactive as it has relatively low affinity to dopamine and 5-HT receptors compared to the parent compound, however, 8-OH loxapine inhibits [14C]5-HT uptake in vitro (IC50 = 2 μM in human platelets).
