Nicotine replacement therapy (NRT), bupropion, nortriptyline, clonidine, and varenicline are all effective, although insufficient evidence exists to recommend one intervention over another (SOR: A, systematic reviews). Effective nonpharmacologic interventions include brief physician advice and more intensive counseling, such as proactive telephone counseling, group and individual counseling, and use of quit lines (SOR: A, systematic reviews)