Norclozapine
clozapine metabolite
“Nor Clozapine”
Symbol in mouth is nor → nitrogen has lost an alkyl substituent
Light blue → cholinergic / muscarinic
Thinking cap → cognitive benefits (M1 agonist)
Hypersalivation (likely multifactorial, M1 contributing)
What it isN-desmethylclozapine, the major active metabolite of clozapine, with muscarinic M1 agonism the parent lacks.
Why it mattersIts M1 agonism is the leading explanation for clozapine’s cognitive and procognitive effects, and its ratio to clozapine tracks adherence and metabolism.
What it changesA norclozapine-to-clozapine ratio above about 0.8 suggests poor adherence with a recent dose; a very low ratio suggests CYP1A2 inhibition.
FDA-approved for
- schizophrenia (metabolite of clozapine)
NO BOXED WARNINGS
Principal riskLittle in its own right; see the parent drug