Drug information of varenicline

Mechanism of effect

Partial neuronal α4 β2 nicotinic receptor agonist; prevents nicotine stimulation of mesolimbic dopamine system associated with nicotine addiction. Also binds to 5-HT3 receptor (significance not determined) with moderate affinity. Varenicline stimulates dopamine activity but to a much smaller degree than nicotine does, resulting in decreased craving and withdrawal symptoms.

Pharmacodynamic

Varenicline is a partial nicotinic acetylcholine receptor agonist, designed to partially activate this system while displacing nicotine at its sites of action in the brain.

Pharmacokinetics

Well absorbed; unaffected by food. Metabolism:Minimal (<10% of clearance is through metabolism). Excretion:Urine (92% as unchanged drug). Time to Peak:Plasma: ~3 to 4 hours. Half-Life Elimination:~24 hours. Protein Binding:≤20%.

Drug indications

Dosage

Smoking cessation: Oral: Initial: Days 1 to 3: 0.5 mg once daily Days 4 to 7: 0.5 mg twice daily Maintenance (≥ Day 8): 1 mg twice daily for 11 weeks; may consider a temporary or permanent dose reduction if usual dose is not tolerated.

Side effects

nausea , Headache , insomnia , vomiting , irritability , Increased risk of suicidal thinking , rash , Depression , malaise , agitation

Interactions

Alerts

patients must be cautioned about performing tasks which require mental alertness (eg, operating machinery or driving).

Points of recommendation

Administer after eating and with a full glass of water.

Pregnancy level

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