Varenicline for smoking cessation: nausea severity and variation in nicotinic receptor genes

This study evaluated association between common and rare sequence variants in 10 nicotinic acetylcholine receptor subunit genes and the severity of nausea 21 days after initiating the standard, Food and Drug Administration-approved varenicline regimen for smoking cessation. A total of 397 participants from a randomized clinical effectiveness trial with complete clinical and DNA resequencing data were included in the analysis (mean age=49.2 years; 68.0% female). Evidence for significant association between common sequence variants in CHRNB2 and nausea severity was obtained after adjusting for age, gender and correlated tests (all P(ACT)<0.05). Individuals with the minor allele of CHRNB2 variants experienced less nausea than did those without the minor allele, consistent with previously reported findings for CHRNB2 and the occurrence of nausea and dizziness as a consequence of first smoking attempt in adolescents, and with the known neurophysiology of nausea. As nausea is the most common reason for discontinuance of varenicline, further pharmacogenetic investigations are warranted.