Varenicline (Trade Name in the EC: Champix, in the USA Chantix), (6R,10S)-7,8,9,10-Tetrahydro-6,10-methano-6H-pyrazino[2,3,h]benzazepine, C13H13N3, M=211,26 g/mol
Varenicline was certified at the end of of 2006 in the European Community for smoking cessation treatment under the trade name Champix® as prescription-requiring medicine, after already the selling takes place in the USA under the trade name Chantix®. Varenicline binds like nicotine with high affinity and selectivity at the α4β2 neuronal nicotinic acetylcholine receptors and prevents thereby nicotine binding. The stimulation of the mesolimbic dopamine system, which reinforces the demand for nicotine, is substantially lower by Varenicline.
The daily uptake is 2 x 1 mg as tablets. Clinical studies showed that the continuous abstinence rate is using Varenicline after 12 weeks clearly higher as using of Zyban® (Bupropione) or placebo (44.0% opposite 29,5% or 17,7%). As Adverse Effects in 30% of the cases nausea appeared, remaining in 3% of cases over the entire income time. Some cases of taste changes are reported.
The active substance Varenicline is a synthetic derivative of the alkaloid Cytisine, which is contained in Laburnum (Laburnum anagyroides). Laburnum was already used in World War II as replacement for nicotine. Cytisine was investigated in Eastern Europe in the last 40 years for smoking cessation treatment and is even certified in Bulgaria under the name Tabex as medicine.