Clozapine was discovered in 1958 by an anesthetist and now it is used for the treatment of schizophrenia. Although the exact mechanism of its action is unknown, the effect of clozapine on schizophrenia is associated with inhibition of dopamine D2 and serotonin 2A receptors.

Clozapine N-oxide is a phase 1 metabolite of antipsychotic drug clozapine, produced by oxidation of clozapine by CYP3A4. Clozapine N-oxide is inert with respect to a wide range of GPCRs. It was used a tool compound in the DREADD (designer receptors exclusively activated by designer drugs) system in which a mutated muscarinic G protein-coupled receptor is activated by an otherwise inert compound, however interpretation of experiments is confounded by the ability of clozapine-N-oxide to convert to clozapine upon administration. Clozapine N-oxide exhibits neuroprotective action by inhibiting of microglial NADPH oxidase.