Varenicline and its role in smoking cessation.

Varenicline is a partial agonist of alpha4beta2 nicotinic receptors. It was recently approved for smoking cessation in the United States. It is administered at a dosage of 0.5 mg once a day for an initial period of 3 days followed by 0.5 mg twice a day for the next 4 days. Following this, the drug is administered at a dosage of 1.0 mg twice a day. The total duration of therapy is 12 weeks. Common adverse effects include nausea, headache, and insomnia. Recent studies show that varenicline is almost twice as effective as bupropion SR in smoking cessation. Given the increased risk of cardiovascular morbidity secondary to smoking, especially in the elderly, varenicline is a major therapeutic tool in the fight against smoking.