Cotinine

Cotinine is the primary metabolite of nicotine, formed in the liver predominantly by the cytochrome P450 2A6 (CYP2A6) enzyme (PubChem CID 8540). It serves as the gold-standard biomarker for assessing exposure to tobacco smoke and nicotine intake due to its relatively long half-life of approximately 16 hours, compared to only 2 hours for nicotine (CDC, 2023). While historically viewed as a pharmacologically inactive byproduct, recent research indicates that cotinine crosses the blood-brain barrier and exhibits neuropharmacological activity (PubMed: 22542445). It has been identified as a weak agonist or positive allosteric modulator of nicotinic acetylcholine receptors (nAChRs), specifically the alpha-7 subtype, which is involved in cognitive function and neuroprotection (Echeverria et al., 2016). These properties have prompted investigations into its potential use as a therapeutic agent for cognitive impairment in Alzheimer's disease and schizophrenia (NIH: PMC3353594). However, in the context of drug discovery, cotinine is generally classified as a metabolite or biomarker rather than a primary therapeutic target. Its clinical utility remains centered on verifying smoking status and monitoring the efficacy of smoking cessation programs.

Other names

(S)-1-Methyl-5-(3-pyridinyl)-2-pyrrolidinone(-)-Cotinine1-Methyl-5-(pyridin-3-yl)pyrrolidin-2-one

Acts as a weak agonist or positive allosteric modulator of nicotinic acetylcholine receptors (nAChRs), particularly the alpha-7 subtype.