Cytisine, also known as baptitoxine and sophorine, is an alkaloid that occurs naturally in several plant genera, such as Laburnum and Cytisus of the family Fabaceae. It has been used medically to help with smoking cessation. Its molecular structure has some similarity to that of nicotine and it has similar pharmacological effects. Like varenicline, cytisine is a partial agonist of nicotinic acetylcholine receptors (nAChRs). Cytisine has a short half-life of 4.8 hours, and is rapidly eliminated from the body. The use of cytisine for smoking cessation remains relatively unknown outside Eastern Europe.
Cytisine is an organic heterotricyclic compound that is the toxic principle in Laburnum seeds and is found in many members of the Fabaceae (legume, pea or bean) family. An acetylcholine agonist, it is widely used throughout Eastern Europe as an aid to giving up smoking. It has a role as a nicotinic acetylcholine receptor agonist, a phytotoxin and a plant metabolite. It is an alkaloid, an organic heterotricyclic compound, a secondary amino compound, a lactam and a bridged compound.