Champix Tablets

Stopping smoking is one of the most significant steps a person can take for their long-term health. For many people, nicotine dependence makes quitting difficult without support. Champix tablets contain varenicline, a prescription medicine specifically developed to help adults stop smoking by acting on the same nicotine receptors in the brain that tobacco targets.

Champix is used as part of a smoking cessation programme that may include behavioural support. A prescription can only be issued following a clinical consultation.

IMPORTANT — NEUROPSYCHIATRIC EFFECTS: Varenicline (Champix) has been associated with changes in behaviour, mood, and mental state, including depression, agitation, hostility, anxiety, and suicidal thoughts or actions. These effects have been reported in patients with and without pre-existing psychiatric conditions. Patients and caregivers should be alert to any changes in mood or behaviour and should contact a prescriber or seek urgent medical help if they occur. Patients with a history of psychiatric illness require careful assessment before varenicline is prescribed and close monitoring during treatment.

Champix is a branded prescription medicine manufactured by Pfizer. The active ingredient is varenicline tartrate. Varenicline is a partial agonist of the alpha-4 beta-2 nicotinic acetylcholine receptor, the principal receptor through which nicotine produces its pleasurable and reinforcing effects in the brain. Champix is specifically developed for smoking cessation and works through a mechanism entirely distinct from nicotine replacement therapy.

Champix is licensed in the UK for smoking cessation in adults. It is taken for a standard 12-week course, with the option of an additional 12-week course for patients who have successfully stopped smoking and wish to reduce the risk of relapse. The SmPC recommends that varenicline is used alongside behavioural support where available. Behavioural therapy alongside pharmacological treatment improves quit rates compared to either approach alone.

Champix is available in two tablet strengths: 0.5 mg and 1 mg. Treatment begins with a titration phase using the 0.5 mg tablet to reduce the risk of nausea before progressing to the 1 mg maintenance dose. Both strengths are required to complete the standard course.

Tobacco addiction support: Pharmacy Planet recommends using Champix alongside stop smoking behavioural support where available. NHS Stop Smoking services are available free of charge across the UK and can significantly improve the chances of successfully quitting.

Varenicline relieves nicotine cravings and reduces the satisfaction of smoking through its partial agonist action at nicotinic acetylcholine receptors.

Partial Agonism at Alpha-4 Beta-2 Nicotinic Receptors

When a person smokes, nicotine binds to alpha-4 beta-2 nicotinic acetylcholine receptors in the brain and stimulates the release of dopamine in the reward pathway, producing the pleasurable reinforcement that drives tobacco addiction. Varenicline binds to these same receptors with high affinity but acts as a partial agonist rather than a full agonist. This means varenicline produces a lower, more moderate level of dopamine release than nicotine, enough to reduce the intensity of nicotine cravings and withdrawal symptoms, but not enough to produce the full reward response of smoking.

Competitive Blockade of Nicotine

In addition to its partial agonist effect, varenicline competitively blocks the binding of nicotine to the same receptors. If a person smokes while taking varenicline, nicotine is unable to bind as effectively to alpha-4 beta-2 receptors because varenicline is already occupying them. This reduces the reward and satisfaction associated with smoking during treatment, which can help to weaken the behavioural reinforcement of the habit.

Together, these two actions, partial receptor stimulation reducing craving and receptor blockade reducing the reward of smoking, form the basis of varenicline's clinical effectiveness for smoking cessation.

Always take Champix exactly as your prescriber instructs. The information below summarises key points from the current UK SmPC. Read the Patient Information Leaflet supplied with your medicine before starting treatment.

Setting a Quit Date

The SmPC recommends setting a target quit date within the first two weeks of starting treatment, typically around day 8 to 14 of the course. Some patients may prefer to set the quit date within the first 5 weeks. Your prescriber will advise on the approach that suits you best.

• Take Champix after eating and with a full glass of water. Taking it with food reduces the risk of nausea, which is the most common side effect.
• Week 1 (days 1 to 3): take one 0.5 mg tablet once daily.
• Week 1 (days 4 to 7): take one 0.5 mg tablet twice daily (morning and evening).
• Week 2 onwards (maintenance): take one 1 mg tablet twice daily (morning and evening). Continue for the remainder of the 12-week course.
• If you experience significant side effects such as intolerable nausea, your prescriber may suggest continuing on the 0.5 mg dose rather than increasing to 1 mg.
• If you have not stopped smoking by the end of the 12-week course, contact your prescriber. A further 12-week course may be considered for patients who have not yet quit but wish to continue trying.
• Do not stop taking Champix abruptly without speaking to your prescriber. Stopping suddenly may cause irritability or other symptoms.
• Monitor your mood, behaviour, and mental state throughout treatment. If you or someone close to you notices any changes in mood, thinking, or behaviour, contact your prescriber promptly.

Champix 0.5 mg Tablets

The 0.5 mg tablet is used during the titration phase in weeks 1 and 2 of treatment. Titration reduces the frequency and severity of nausea, which is common at the start of varenicline treatment. During the first 3 days, one 0.5 mg tablet is taken once daily. From day 4 to day 7, one 0.5 mg tablet is taken twice daily. After day 7, the dose is increased to the 1 mg maintenance dose. Patients who cannot tolerate the 1 mg dose may continue at 0.5 mg twice daily throughout the course per prescriber advice.

Champix 1 mg Tablets

The 1 mg tablet is the maintenance dose, taken twice daily (morning and evening) from week 2 onwards for the remainder of the 12-week course. This is the dose at which varenicline's full therapeutic effect for smoking cessation is achieved. The total standard course is 12 weeks. An additional 12-week course at 1 mg twice daily may be prescribed for patients who have successfully stopped smoking to reduce relapse risk. All dose decisions are made by your prescriber.

Champix can cause side effects. The information below is based on the current UK SmPC. Refer to the Patient Information Leaflet for the full list.

Common Side Effects (may affect up to 1 in 10 people)

• Nausea. This is the most commonly reported side effect and is most frequent in the first few weeks of treatment. Taking Champix after food and with a full glass of water significantly reduces nausea. It often improves as treatment continues.
• Headache.
• Insomnia and abnormal or vivid dreams.
• Dizziness.
• Constipation.
• Dry mouth.

Neuropsychiatric Side Effects: Monitor Closely

Varenicline has been associated with serious neuropsychiatric adverse effects. These include:

• Changes in mood or behaviour such as agitation, aggression, hostility, or unusual changes in thinking.
• Low mood or depression.
• Suicidal thoughts or actions.
• Worsening of pre-existing psychiatric conditions.

These effects have been reported in patients with and without a history of psychiatric illness. You, your family, and those who care for you should monitor for any changes in mood, thinking, or behaviour throughout the course of treatment. If any such changes occur, stop taking Champix and contact your prescriber or seek urgent medical attention.

Cardiovascular Effects

Clinical trial data has raised questions about cardiovascular events in patients with pre-existing cardiovascular disease taking varenicline. The current UK SmPC and MHRA guidance indicate that the cardiovascular benefits of stopping smoking outweigh the potential risks in most patients, but patients with established cardiovascular disease should be assessed carefully. Your prescriber will take this into account.

Serious Side Effects: Seek Urgent Medical Attention

Go to your nearest accident and emergency department or call 999 immediately if you experience:

• Any thoughts of suicide or self-harm, or if a person around you notices sudden or severe changes in your mood or behaviour.
• Severe skin reactions such as blistering or peeling of the skin or mucous membranes.
• Signs of a serious allergic reaction such as swelling of the face, lips, tongue, or throat, or difficulty breathing.

Report any suspected side effect to your prescriber, pharmacist, or via the MHRA Yellow Card scheme at yellowcard.mhra.gov.uk.

Champix May Be Suitable If You:

• Are an adult aged 18 or over who smokes and wishes to stop.
• Have attempted to stop smoking before and found nicotine replacement therapy or willpower alone insufficient.
• Are able to set a target quit date and commit to a 12-week course of treatment.
• Do not have contraindications and have discussed your full medical history with a prescriber.

Champix Requires Careful Assessment or May Not Be Suitable If You:

• Have a current or past history of depression, bipolar disorder, schizophrenia, or other serious psychiatric conditions. Varenicline can worsen psychiatric illness. A careful prescriber assessment of the risks and benefits is required before prescribing in these patients.
• Are pregnant or planning to become pregnant. Varenicline is not recommended during pregnancy. Nicotine replacement therapy is preferred for pregnant smokers. Contact your prescriber to discuss the safest approach.
• Are breastfeeding.
• Have severe kidney impairment. Dose reduction to 1 mg once daily (rather than twice daily) is required. The prescriber will assess kidney function before prescribing.
• Are under 18 years of age.
• Have a known allergy or hypersensitivity to varenicline or any excipient listed in the SmPC.

Champix has relatively few drug interactions compared to many other prescription medicines. Key points:

• Nicotine replacement therapy (patches, gum, lozenges): combined use with varenicline may increase the frequency of nausea, vomiting, headache, dizziness, and fatigue. The SmPC does not contraindicate the combination but advises caution. Discuss with your prescriber if you wish to use both.
• Warfarin and other anticoagulants: stopping smoking itself, rather than varenicline, can affect warfarin metabolism. If you take warfarin, your INR should be monitored more closely when you stop smoking.
• Insulin and antidiabetic medicines: stopping smoking can increase insulin sensitivity. Patients with diabetes should monitor blood glucose more closely when stopping smoking as dose adjustments of antidiabetic medicines may be needed.
• Alcohol: varenicline may increase the effects of alcohol. Exercise caution with alcohol during treatment.

Your prescriber will review your current medicines before issuing a prescription.

Champix is a Prescription Only Medicine. The clinical consultation is the essential first step. A prescription will only be issued if a registered prescriber concludes, based on their individual assessment of your circumstances, that varenicline is clinically appropriate for you.

During your online consultation with Pharmacy Planet, a registered prescriber will review the information you provide. This includes your smoking history, previous quit attempts, current medicines, psychiatric history, kidney function, and cardiovascular history. Given the neuropsychiatric monitoring requirement, the prescriber will assess whether online prescribing is appropriate for your individual circumstances or whether face-to-face support with your GP or NHS Stop Smoking service is more suitable.

Not all consultations will result in a prescription. The prescriber may recommend nicotine replacement therapy as a safer first-line option or request further clinical information particularly where there is a history of psychiatric illness. This process is designed to protect your safety.

Champix works best when used alongside behavioural support. NHS Stop Smoking services are free, widely available, and significantly improve quit rates. Your prescriber may recommend attending one of these services alongside your Champix prescription.

Store below 30°C. Store in the original packaging. Keep out of the sight and reach of children. Do not use after the expiry date printed on the packaging. Do not dispose of medicines via household waste or wastewater. Return unused or out of date tablets to your pharmacist for safe disposal. Full storage instructions are provided in the Patient Information Leaflet supplied with your medicine.

Pharmacy Planet is a GPhC-registered online pharmacy providing access to prescription medicines through a clinically led consultation process. Our registered prescribers and pharmacists are committed to patient safety, clinical accuracy, and responsible prescribing. We follow GPhC standards, MHRA guidance, and ASA advertising regulations in all aspects of our service. For medicines with neuropsychiatric monitoring requirements such as varenicline, our prescribers give particular attention to psychiatric history and the suitability of online prescribing for each individual patient. Every prescription is reviewed and dispensed by qualified healthcare professionals.

If you have questions about Champix, varenicline, or stop smoking support, our pharmacy team is available to help. We are committed to transparent, patient centred care.

References

1. Electronic Medicines Compendium (eMC). Champix 0.5 mg and 1 mg film-coated tablets — Summary of Product Characteristics. https://www.medicines.org.uk/emc. Accessed May 2026.
2. National Institute for Health and Care Excellence (NICE). Stop smoking interventions and services. NICE guideline NG209. https://www.nice.org.uk/guidance/ng209. Accessed May 2026.
3. NHS. Stop smoking treatments. https://www.nhs.uk/live-well/quit-smoking/stop-smoking-treatments. Accessed May 2026.
4. Joint Formulary Committee. British National Formulary (BNF). Varenicline. BMJ Group and Pharmaceutical Press. https://bnf.nice.org.uk. Accessed May 2026.
5. Medicines and Healthcare products Regulatory Agency (MHRA). Varenicline (Champix): updated guidance on neuropsychiatric adverse effects. https://www.gov.uk/drug-safety-update. Accessed May 2026.
6. Medicines and Healthcare products Regulatory Agency (MHRA). Yellow Card — report a side effect. https://yellowcard.mhra.gov.uk. Accessed May 2026.