Varenicline

Varenicline is a partial nicotine receptor agonist developed specifically as a smoking cessation aid. It works by partially stimulating the alpha-4-beta-2 nicotinic acetylcholine receptor, reducing cravings and withdrawal symptoms while simultaneously blocking nicotine from fully activating the receptor if the patient smokes. This dual action reduces both the urge to smoke and the rewarding effects of smoking. Varenicline is the most effective single-agent pharmacotherapy for smoking cessation.

How to Take Varenicline

Set a quit date and start varenicline one to two weeks before you plan to stop smoking. Take the tablets with food and a full glass of water to reduce nausea. The dose is built up gradually: 0.5 mg once daily for days 1 to 3, then 0.5 mg twice daily for days 4 to 7, then 1 mg twice daily from day 8 onwards.

Treatment usually lasts 12 weeks. Patients who successfully quit may benefit from a further 12 weeks at 1 mg twice daily to reduce the risk of relapse. If you do not manage to quit during the first course, discuss with your doctor whether another attempt is worthwhile.

Days 1 to 3: 0.5 mg once daily. Days 4 to 7: 0.5 mg twice daily. Day 8 to end of treatment: 1 mg twice daily. Treatment: 12 weeks, extendable to 24 weeks.

Common Side Effects

Common side effects include:

• Nausea (the most common, taking it with food usually helps)
• Insomnia and vivid or unusual dreams
• Headache
• Wind and constipation

Nausea is most common in the first few weeks and generally improves. Varenicline has been associated with mood changes, depression, and in rare cases suicidal thoughts. Tell your doctor straight away if you notice significant changes in mood, behaviour, or thought patterns during treatment. It is not always clear whether these are related to varenicline or to nicotine withdrawal itself.

Earlier safety concerns about neuropsychiatric effects and cardiovascular events have been largely addressed by the EAGLES trial, which found no significant increase in these events. However, monitor for mood changes, agitation, or suicidal thoughts, particularly in patients with pre-existing psychiatric conditions.

Contraindicated in known hypersensitivity to varenicline. Use with caution in severe renal impairment (dose reduction to 1 mg daily).