What is Champix used for?

Champix (varenicline) is a prescription medicine used to help adults stop smoking. It is a partial nicotinic acetylcholine receptor agonist — it both reduces cravings and withdrawal symptoms and decreases the rewarding effects of cigarettes if the patient continues to smoke during treatment.

How effective is Champix compared to other stop-smoking treatments?

WHO finds higher quit rates than placebo, bupropion and single-form nicotine replacement therapy (NRT), but no clear difference versus combination NRT. Placebo-controlled trials are not the same as unassisted quit attempts. Behavioural support improves outcomes.

What are the most common side effects of Champix?

The most commonly reported side effect is nausea, affecting up to one third of patients. This is usually mild to moderate and often improves after the first few weeks. Taking Champix with food and a full glass of water can help reduce nausea. Vivid or unusual dreams are classified as very common.

Can Champix cause mood changes or depression?

Mood changes, including depression, agitation, and changes in behaviour, have been reported in some patients taking varenicline. It is important to note that nicotine withdrawal itself can also cause mood changes, making it difficult to attribute causation. Patients with a history of psychiatric illness should discuss this with their doctor before starting Champix. If serious changes in mood, behaviour or thinking occur, stop varenicline immediately and contact a healthcare professional for reassessment.

How long is the Champix course?

The standard course of Champix is 12 weeks. Patients who successfully quit smoking during this period may benefit from a further 12 weeks of treatment to reduce the risk of relapse. The total recommended treatment duration is therefore up to 24 weeks for sustained benefit.

Champix (Varenicline): Online Medical Assessment

What is Champix?

Champix (varenicline) is a prescription-only medicine approved by the European Medicines Agency (EMA) to support adults in stopping smoking. WHO recommends varenicline as one option; this does not establish superiority over combination NRT or present stock.

Champix is not a nicotine product — it works through a different mechanism from nicotine replacement therapy (NRT). It acts directly on the nicotinic receptors in the brain that are involved in nicotine addiction, both relieving withdrawal symptoms and reducing the satisfaction associated with smoking.

How does Champix work?

Varenicline is a partial agonist at alpha-4 beta-2 nicotinic acetylcholine receptors — the receptors most strongly associated with nicotine dependence and the rewarding effects of smoking.

Its dual mechanism of action is what makes it distinctive:

Partial agonist activity: Varenicline stimulates nicotinic receptors at a lower level than nicotine, reducing cravings and withdrawal symptoms without delivering a full nicotine “hit”
Receptor blockade: By occupying the receptor, varenicline partially blocks nicotine from binding if the patient smokes during treatment, reducing the rewarding effect of cigarettes and thereby weakening the positive reinforcement of smoking

This combined action — reducing withdrawal discomfort while also diminishing the reward from smoking — makes varenicline particularly effective at supporting sustained abstinence.

Who is Champix for?

Champix is indicated for adult smokers who are motivated to stop smoking. A doctor assesses previous attempts, medical history and preferences; prior NRT use does not establish suitability.

Important considerations before starting Champix:

Patients with a history of psychiatric illness (including depression, bipolar disorder, schizophrenia) should discuss the risks and benefits with their doctor before starting treatment
Severe renal impairment requires the reduced regimen below; end-stage renal disease: use is not recommended
Champix is not recommended for use during pregnancy
During breastfeeding, the clinician must weigh whether to stop breastfeeding or avoid treatment, considering benefit to the infant and mother
Adolescents under 18 years should not use Champix

The most effective smoking cessation approach combines pharmacological treatment with structured behavioural support, such as counselling or a stop-smoking programme.

Dosage

Champix tablets are swallowed whole with water, with or without food. The dose is escalated gradually to reduce the risk of nausea.

Phase	Dose	Duration
Days 1–3	0.5 mg once daily	3 days
Days 4–7	0.5 mg twice daily	4 days
Weeks 2–12	1 mg twice daily	11 weeks
Optional extension	1 mg twice daily	Up to 12 additional weeks

The table applies to adults without a required renal dose reduction. For creatinine clearance below 30 mL/min, use 0.5 mg once daily for 3 days, then 1 mg once daily. End-stage renal disease: treatment is not recommended. The prescriber may reduce the dose for intolerance.

Patients should set a quit date, ideally 1–2 weeks after starting Champix, to allow blood levels to build up. Some patients may prefer to start Champix and then choose a flexible quit date within the first month of treatment.

Side effects

Very common side effects

Nausea: The most frequently reported side effect; typically mild to moderate and often reduces over time. Discuss troublesome nausea with the prescriber.
Vivid, unusual, or abnormal dreams
Headache
Insomnia

Common side effects

Increased appetite
Fatigue
Dry mouth
Constipation or diarrhoea
Dizziness

Important risks to monitor

Neuropsychiatric effects: Changes in mood, behaviour, or thinking, including depression, agitation, hostility, suicidal ideation. These have been reported in patients taking Champix; the contribution of nicotine withdrawal versus the medicine is debated. Patients with existing psychiatric conditions should be closely monitored. If serious neuropsychiatric symptoms develop, stop varenicline immediately and contact a healthcare professional for reassessment.
Cardiovascular events: Some data has suggested a possible increase in cardiovascular events in patients with established cardiovascular disease. This should be discussed with the prescribing doctor.
Seizures: Uncommon; Champix should be used with caution in patients with a history of seizure disorders.

Champix vs alternatives

Treatment	Active Ingredient	Mechanism	Prescription Required	Relative Efficacy
Champix	Varenicline	Nicotinic partial agonist	Yes	Better quit rates than single-form NRT
Zyban	Bupropion	Dopamine/noradrenaline reuptake inhibitor	Yes	WHO-recommended option
NRT (patches/gum/lozenges)	Nicotine	Nicotine replacement	Generally No	WHO-recommended option

WHO found no clear difference between varenicline and combination NRT. However, individual patient factors — including tolerability, history, and preference — should guide treatment selection.

Online assessment for Champix (Varenicline)

Champix is a prescription-only medicine in all EU member states. It cannot be legally dispensed without a valid prescription from a qualified medical professional.

Prescrivia operates as a technology intermediary, connecting patients with independent doctors for online health assessments. We do not prescribe medicines, employ doctors, or sell medicines directly.

Complete a health assessment: Provide information about your smoking history, motivation to quit, medical history, and current medications.
Doctor review: An independent doctor reviews your assessment. If varenicline is clinically appropriate, they may issue a prescription.
Prescription and fulfilment: If a prescription is issued, dispensing is the responsibility of a licensed pharmacy, subject to applicable national rules and product availability.

Important: Prescrivia does not guarantee that a prescription will be issued. All prescribing decisions are made independently by qualified medical professionals.

Important safety information

Do not take Champix if you are allergic to varenicline or any excipient. Stop treatment and get immediate medical advice for swelling of the face/throat or a rash/skin reaction. Seek emergency care for signs of heart attack or stroke.

Tell your doctor if you:

Have a history of depression, bipolar disorder, or other psychiatric conditions
Have or have had kidney disease
Take medicines whose doses may need review when smoking stops, such as theophylline, warfarin or insulin

Serious mood, behaviour or thinking changes: Stop varenicline immediately and contact a healthcare professional; disclosure alone is not enough.

Driving: Some patients experience dizziness or somnolence with Champix. Do not drive until you know how the medicine affects you.

Alcohol: Patients have reported increased alcohol intoxication or unusual behaviour while drinking alcohol during Champix treatment. Take care with alcohol consumption.

In Spain, distance sale of prescription medicines is prohibited under Article 3.5 of Royal Legislative Decree 1/2015. An online assessment does not remove this restriction. Dispensing and access depend on the exact product and applicable national rules.

Sources

Medical information on this page is based on the following sources:

This editorial information does not replace the full product information. It is provided for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional for advice relevant to your individual health circumstances.

Champix (Varenicline)

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Strengths and types