Doses and duration of pharmacological treatments to quit smoking
| Medication | Mechanism of action | Dosage and treatment duration | Side-effects |
| Nicotine replacement therapy | Acts at the level of nicotinic central nervous system receptors | 16-h patches >10 cigarettes per day: 25 mg once daily×6 weeks 15 mg once daily×4 weeks 10 mg once daily×2 weeks 5 mg once daily×2 weeks <10 cigarettes per day: 10 mg once daily×6 weeks 5 mg once daily×2 weeks 24-h patches >10 cigarettes per day: 21 mg once daily×6 weeks 14 mg once daily×4 weeks 7 mg once daily×2 weeks <10 cigarettes per day: 14 mg once daily×6 weeks 7 mg once daily×2 weeks | Redness or itching of skin where patch applied, urticaria, headache, dizziness, nausea/vomiting, insomnia |
| Chewing gum 2–4 mg or tablets 1–2 mg if craving | Mouth soreness, throat irritation, jaw ache, dyspepsia, flatulence, nausea, emesis, unpleasant taste, possible allergic reactions | ||
| Bupropion | Inhibits neuronal reuptake of dopamine and norepinephrine in the nucleus accumbens and locus coeruleus | ≥12 weeks: 150 mg per 12 h First week progressive dose | Insomnia (most common), dry mouth, anxiety, irritability, restlessness, headache, tinnitus, skin rash, seizures (rare and most alarming) |
| Varenicline | Partial agonist for the α4β2 nicotinic acetylcholine receptor (dopamine release in the nucleus accumbens) | ≥12 weeks: Days 1–3: 0.5 mg once daily Days 4–7: 0.5 mg twice daily Days 8+: 1 mg twice daily | Nausea (most common), insomnia, abnormal dreams, sleep disturbance, dyspepsia, abdominal pain, constipation, flatulence, emesis, dizziness, dry mouth |