Which statement about varenicline's mechanism is NOT true?

• A. It is a partial agonist at alpha4beta2 receptors
• B. It prevents nicotine from binding to receptors
• C. It stimulates dopamine release
• D. It is a full agonist at beta2 receptors

Answer: (D)

Varenicline works by binding as a selective partial agonist at the alpha4beta2 nicotinic acetylcholine receptor. This dual action means it can provide a modest dopaminergic stimulus to ease withdrawal while occupying the receptor so nicotine cannot produce a strong dopamine boost when someone smokes. That makes it effective at reducing cravings and blocking reinforcement.

So statements describing varenicline as a partial agonist at alpha4beta2, and its roles in both blocking nicotine binding and stimulating some dopamine release, fit the mechanism. The claim that it is a full agonist at beta2-containing receptors is not correct; varenicline is not a full agonist at those receptors.