Drug used for smoking cessation is:

Ans. (A) Vareniciline(Ref: Goodman and Gilman 13th/e p437-438)Anti-Smoking drugsVareniciline: It is a direct acting nicotinic agonist having selectivity for a4b2 isoform of NN receptors. It can be used orally and has a half life of 14-20 hours. Its adverse effects include headache, nausea and sleep disturbances.Nicotine: A transdermal patch containing nicotine is applied to the patient's body. The dose of nicotine is then slowly decreased and finally withdrawn. It is effective in only 18-20% of the patients. It is also available in the form of lozenges.Bupropion: It is an anti-depressant drug that can be used for cessation of smoking. It acts by inhibition of neuronal reuptake of 5-HT, NE and DA. The duration of treatment is for 8-10 weeks. It can result in CNS stimulation leading to seizures.Clonidine: It is a very effective drug for reducing the withdrawal effects of nicotine. It is better than nicotine chewing gum as it can be used in patients with cardiac diseases also. It decreases the craving as well as is useful for insomnia.Rimonabant: It is a cannabinoid receptor antagonist that results in the increased 5-HT and dopamine levels. The adverse effects include nausea, vomiting, suicidal tendencies (depression) and anxiety.