has role is deprotonated form of serotonergic agonist bridged compound organic heterotetracyclic compound nicotinic acetylcholine receptor agonist secondary amino compound varenicline CHEBI:84500 An organic heterotetracyclic compound that acts as a partial agonist for nicotinic cholinergic receptors and is used (in the form of its tartate salt) as an aid to giving up smoking. varenicline(1+)