Evidence from animal and human studies supports a role for variation in the CHRNA4 gene in altering the sensitivity of α4-containing nAChRs and response to NRT. Initial evidence suggests that CHRNA4 variation may alter sensitivity to nicotine and quitting success with forms of NRT that reach the CNS more quickly (nasal spray). Yet, these data have yet to be replicated and more work is needed to identify functional SNPs that may yield more robust and reproducible associations with cessation phenotypes.
