[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Smoking cessation medicines](https://durgical.com/en/pharmacology/classes/smoking-cessation-medicines/) › Varenicline

[Pharmacology](https://durgical.com/en/pharmacology/) · [Smoking cessation medicines](https://durgical.com/en/pharmacology/classes/smoking-cessation-medicines/)

# Varenicline

A nicotinic receptor partial agonist that eases craving and makes smoking less rewarding. Nausea and vivid dreams are common.

Updated 2026-11-01

- Class: [Smoking cessation medicines](https://durgical.com/en/pharmacology/classes/smoking-cessation-medicines/)
- Receptor: Nicotinic acetylcholine receptor α4β2
- ATC code: N07BA03
- WHO Model List of Essential Medicines

◎**Nicotinic acetylcholine receptor α4β2**Varenicline

ⓘ The figure shows varenicline itself bound to the human α4β2 nicotinic acetylcholine receptor.

**Target in 3D:** Nicotinic acetylcholine receptor α4β2. PDB structure 6UR8 (RCSB PDB, public domain). [View the structure at RCSB PDB](https://www.rcsb.org/structure/6UR8) · Drag to rotate · pinch to zoom

## Mechanism of action

Varenicline, designed from cytisine, binds α4β2 nicotinic receptors as a partial agonist. It stimulates them enough to ease craving and withdrawal, while occupying the site so nicotine from a cigarette binds less and drives less mesolimbic dopamine reward.

- Binds α4β2 nicotinic receptors as a partial agonist
- Partial stimulation eases craving and withdrawal
- Nicotine is blocked: smoking rewards less

## Pharmacokinetics

**Metabolism**
Minimal

**Elimination**
Mainly in the urine, about 92% unchanged

**Half-life**
About 24 hours

## Indications

- Aid to smoking cessation [Tobacco use disorder →](https://durgical.com/en/conditions/tobacco-use-disorder/)

## Adverse effects

### Common

- Nausea (the most common)
- Abnormal dreams and insomnia
- Constipation, flatulence and vomiting

### Serious (rare, important)

- Neuropsychiatric events, including mood changes and suicidal thoughts
- Seizures
- Stronger intoxicating effects of alcohol
- Cardiovascular events
- Sleepwalking, angioedema and serious skin reactions

## Contraindications

- Serious hypersensitivity or skin reaction to varenicline

## Key interactions

**Nicotine patch**
More adverse effects than nicotine replacement alone

**Alcohol**
Stronger intoxication; alcohol intake is reduced

**Theophylline, warfarin, insulin (effect of quitting smoking)**
Their effects may change after stopping smoking; doses may need review

## What is monitored

- Mood, behaviour and suicidal thoughts
- Kidney function
- Smoking status and adherence

## Administration and safety

- Given by mouth after food with a full glass of water
- Usually started one week before the chosen quit date
- Dose adjusted in severe kidney impairment

## Nursing care

- Ask about mental health history before starting
- Teach to report mood changes, agitation or suicidal thoughts at once
- Teach to be careful driving until the effect is known and to cut down alcohol
- Offer counselling alongside the medicine

## Pregnancy and breastfeeding

Available data have not shown more major birth defects than in women who smoke, but a risk cannot be ruled out.

## Memory aid

Varenicline: «Very Easy Nicotine Exit» – partial agonist: eases craving, blocks the buzz; watch mood.

## Test yourself

Think of the answer, then tap the question to see it.

## How does varenicline make smoking less rewarding?

As a partial agonist it occupies α4β2 receptors and blocks nicotine from binding.

## When is varenicline usually started relative to the quit date?

About one week before the chosen quit date.

## Why is the varenicline dose adjusted in severe kidney disease?

About 92% is excreted unchanged in the urine.

## What is the most common adverse effect of varenicline?

Nausea.

[Add to my cards (4)](https://durgical.app/estudiar/?add=/en/pharmacology/varenicline/)

## Related drugs

- [Nicotine (replacement therapy)](https://durgical.com/en/pharmacology/nicotine/)
- [Cytisine](https://durgical.com/en/pharmacology/cytisine/)

## Related conditions

- [Tobacco use disorder](https://durgical.com/en/conditions/tobacco-use-disorder/)

[← Back to the class: Smoking cessation medicines](https://durgical.com/en/pharmacology/classes/smoking-cessation-medicines/)

Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: [DailyMed - VARENICLINE tablet, film coated VARENICLINE kit](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=78d1857f-8708-5410-792f-4a3e5e7971a5) (DailyMed (U.S. National Library of Medicine), 2026); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=N07BA03) (WHO Collaborating Centre for Drug Statistics Methodology, 2026); Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 13 (McGraw Hill, 2023); [6UR8: CryoEM structure of human alpha4beta2 nicotinic acetylcholine receptor in complex with varenicline](https://www.rcsb.org/structure/6UR8) (RCSB Protein Data Bank, 2020).

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Representative model, for educational purposes only.

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