Varenicline

Mechanism of action

Partial agonist at alpha-4 beta-2 nicotinic receptors. Gives enough dopamine release to ease craving and withdrawal, while blocking nicotine from smoking so cigarettes are less rewarding.

Dosing

Adult

Start 1 week before the quit date: 0.5 mg daily on days 1–3, 0.5 mg twice daily on days 4–7, then 1 mg twice daily for 12 weeks (a further 12 weeks may be added)

CrCl <30 mL/min: maximum 0.5 mg twice daily.