Varenicline efficacy

Jorenby DE, Hays JT, Rigotti NA, Azoulay S, Watsky EJ, Williams KE, et al (2006) Efficacy of varenicline, an alpha4beta2 nicotinic acetylcholine receptor partial agonist, vs placebo or sustained-release bupropion for smoking cessation a randomized controUed trial. JAMA 296(l) 56-63... 

The partial agonistic activity was determined via a functional electrophysi-ological assay in Xenopus oocytes at 10 pM of the test compound relative to 10 pM of nicotine, or upon co-administration of both. These competition experiments demonstrated that varenicline possesses only 68% of the efficacy of nicotine, while the efficacy of nicotine itself is reduced to 34 %. Extensive in vivo studies showed that oral administration of varenicline raises the release of dopamine in the Nucleus accumbens, but on the other hand, it attenuates the effect of nicotine. 

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