The Side Effects of Champix vs Alternative Treatments
Champix is an extremely effective stop-smoking medication that can more than double your chances of kicking the habit. It was originally recalled from the UK market in 2021 and returned in 2025 after approval from the European Medicines Agency (EMA) and the Medicines and Healthcare products Regulatory Agency (MHRA).
In the years that Champix was unavailable, several other treatments were approved in its place, all of them providing smokers with essential support in the fight against nicotine. Now that Champix has returned, should you opt for the most well-known name or choose one of the alternatives?
One of the main factors to consider when choosing different medications is the potential side effects and how they will affect you. So, how do the side effects of Champix compare against its competitors?
This article will explore the various Champix (varenicline) side effects and pit them head-to-head against the alternative treatments, so you can determine which treatment sounds best for your circumstances.
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What are the Side Effects of Champix?
Like all medications, Champix has the potential to cause side effects. The most common of these is nausea, reported in 57% of varenicline users by one study. Other common side effects include:
- Insomnia or abnormal dreams
- Headache
- Sinus and throat inflammation
- Chest infection
- Changes in appetite
- Sleepiness
- Dizziness
- Digestive problems
- Skin rashes
- Joint and muscle aches
Around 1 in 10 people on Champix will experience one or more of these symptoms. However, they are usually mild and improve or disappear within the first few weeks of treatment.
Much rarer, but potentially more serious, Champix (varenicline) side effects include:
- Extreme anxiety
- Tremors or seizures
- Conjunctivitis
- Rapid heart rate or heart palpitations
- Increased blood pressure
- Stroke
- Disturbed vision
- Diabetes
- Sleep walking
- Mood disturbances
- Suicidal thoughts
Severe Champix tablets side effects are very uncommon, but an estimated 17% of people discontinue Champix because of uncomfortable symptoms like nausea or insomnia. Unfortunately, stopping treatment often hampers the person’s efforts to quit smoking. In cases such as these, it may be worth considering a different anti-smoking medication (i.e., Cytisine or Zyban).
If you’re concerned about the side effects of anti-smoking medications, speak with a licensed clinician for more information. A healthcare professional can assess your personal needs and help you make better-informed decisions about your stop-smoking treatment plan.
How Do the Side Effects Of Champix Compare Against Other Stop Smoking Medications?
Varenicline, Zyban, and Cytisine are the main Champix alternatives available on prescription in the UK. Researchers have found these medications effective for smoking cessation, and, though their side effects are similar or identical to those of Champix, they may occur at different rates. Let's take a look at how the side effects of Champix compare to those of the alternatives on the market.
Varenicline vs Champix Side Effects
Champix is the brand name for varenicline, which is the active ingredient in this medication. Pfizer recalled Champix from global markets in 2021 after regulators found higher-than-acceptable levels of nitrosamines in the drug. However, it returned to the UK market in July 2025 after the manufacturer took steps to eliminate contaminants from the drug.
There is no pharmacological difference between Champix and generic varenicline, so their potential side effects are identical. The most common of these, thought to affect more than 1 in 10 people, are:
- Nausea
- Inflammation of the nose and throat
- Insomnia
- Abnormal dreams
- Headaches
Nausea is by far the most commonly reported side effect of varenicline, affecting around 19 of every 100 users. Fortunately, this is usually mild and improves within the first few weeks of treatment. The second most common is insomnia and/or unusual dreams, which affect 5 in 100 people.
Varenicline Smoking Cessation
- Reduces cravings & withdrawal symptoms
- Blocks the rewarding effect of smoking
- Higher long-term quit rates
Zyban vs Champix Side Effects
Zyban and Champix are both anti-smoking medications, but they work differently and may cause different side effects. Zyban contains the active ingredient bupropion hydrochloride, also known as bupropion. Originally developed as an antidepressant, bupropion is also used to aid smoking cessation.
Researchers aren’t sure exactly how Zyban helps people to quit smoking, but it may influence brain pathways associated with addiction and withdrawal. The most frequent Zyban side effects, affecting at least 1% of users, are:
- Agitation
- Dry mouth
- Headache
- Constipation
- Nausea and/or vomiting
- Dizziness
- Excessive sweating
- Tremor
- Insomnia
- Blurred vision
- Elevated heart rate
- Confusion
- Rash
- Hearing problems
More rarely, Zyban can cause neuropsychiatric symptoms such as:
- Mood changes
- Psychosis
- Hallucinations
- Paranoia
- Delusions
- Homicidal ideation
- Aggression
- Agitation
- Anxiety
- Suicidal ideation
- Mania
Some studies have also reported a potential link between varenicline use and neuropsychiatric events. However, this relationship is unconfirmed, and further research has suggested that varenicline does not increase a person’s risk of neuropsychiatric symptoms.
Champix and Zyban cause many of the same side effects, including nausea, vomiting, sleep problems, dizziness, constipation, and skin rash. However, they occur at different rates with each medication. For example, the most common side effect of Zyban is insomnia (affecting 21.9% of users), and the most common side effect of Champix is nausea (affecting 28.1% of people).
Zyban
- Suppresses cravings & withdrawal symptoms
- Nicotine-free
- May improve mood during quitting
Cytisine vs Champix Side Effects
Cytisine is a popular alternative to Champix, as it has similar effects (both medications reduce withdrawal symptoms and cravings), and is considered a safe and effective way to quit smoking. The side effects of Cytisine are comparable to those of Champix, and the most common of these include:
- Nausea
- Dizziness
- Irritability
- Diarrhoea
- Rash
- Fatigue
- Sleep problems
- Headaches
- Increased heart rate
- Appetite changes
- Heartburn
- Constipation
- Muscle pains
Though the side effects of Champix and Cytisine are very similar, research suggests that they are less frequent among those using Cytisine. This study also found that the reduced incidence of side effects among cytisine users translated to a lower discontinuation rate, so people are less likely to stop cytisine treatment early.
The standard treatment plan for Cytisine is also much shorter than that of Champix (25 days vs. 12 weeks). Therefore, it may be easier to tolerate the side effects of Cytisine because they are shorter in duration.
Cytisine
- Natural origin
- Reduces cravings and withdrawal symptoms
- Short, structured treatment course
How Long Do Side Effects Last?
The side effects of anti-smoking medications can be uncomfortable, but they typically resolve soon after starting treatment. One study reported that the most common side effects of Champix (nausea, insomnia, headache, abnormal dreams, constipation, and abdominal pain) were mostly mild and went away after a few weeks.
Side effects of Cytisine often affect the gastrointestinal tract. As with Champix, these are usually mild to moderate and resolve over the course of treatment.
Zyban causes different side effects than Champix and Cytisine, and, most notably, can cause mood and behavioural changes. These symptoms can occur at any time, but are most common in the early stages of treatment. Zyban side effects may go away as your body gets used to the medication, but for some people, they don’t resolve until they complete treatment.
Most of the time, the side effects caused by anti-smoking medications are mild and short-lived. However, they can be uncomfortable and, in some cases, more severe. If you have concerns about the side effects of Champix, Cytisine, or Zyban, reach out to a licensed clinician for guidance.
How to Manage Side Effects
Anti-smoking medications often cause side effects, but they typically get better within the first few weeks of treatment. In the meantime, you may be able to reduce their impact with home remedies and lifestyle changes.
- Nausea: Taking your anti-smoking medication with food or a full glass of water may help to minimise nausea. Sipping cold drinks, getting some fresh air, or drinking ginger or peppermint tea may also help.
- Headaches: Taking over-the-counter painkillers, like paracetamol, and drinking plenty of water can counteract headaches caused by anti-smoking medications. It can also help to avoid alcohol.
- Heartburn: If you have heartburn, avoid eating spicy or rich foods and don’t eat directly before bedtime. Over-the-counter medications (i.e., antacids) can also relieve symptoms.
- Diarrhoea: If you experience diarrhoea when taking anti-smoking medications, drink plenty of fluids to avoid dehydration. Speak to a healthcare professional if you have severe or prolonged gastrointestinal issues.
- Dizziness: If you get dizzy, sit or lie down until it passes. If this side effect is severe or persistent, speak to a licensed clinician—they may recommend reducing your dose.
- Inflammation in the throat and nose: Anti-inflammatory medications like ibuprofen can help to address swelling in the throat and nasal passages.
Some side effects of anti-smoking medications may require the attention of a healthcare professional. For example, insomnia and mood changes (which are more common among people on Zyban) should be discussed with a licensed clinician.
Effective Smoking Cessation Support from Prescription Doctor
Quitting smoking takes a great deal of willpower and determination. While medications such as Champix, Varenicline, Zyban, and Cytisine are extremely effective, they can’t complete the job alone. You have to be fully committed to the cause.
If this seems like a mammoth task, the good news is that you don’t need to go through the journey alone. Help is at hand. At Prescription Doctor, we’ve helped countless individuals just like you to kick the habit and enjoy a new lease of life.
Our service begins with our stop-smoking treatments. Simply choose the option that best suits you, then complete a short medical questionnaire for our specialist clinicians to review. If approved before 3pm on a weekday, your medication will be dispatched in plain packaging and eligible for next-day delivery. Should the treatment be deemed unsuitable, an alternative might be suggested.
We will regularly check in with you to monitor progress and ensure everything is working as it should. Our clinicians are also on hand to answer any queries you may have. A holistic service that’s built around you.
From advice for social smokers to information about the impact stopping smoking has on your body, to outlining the quit smoking timeline, our website has a wealth of information at your fingertips — so you have everything you need to know before starting your smoke-free journey.
Take the first steps toward a brand-new you and begin your consultation with Prescription Doctor today.
Sources
- EMA: Nitrosamine impurities in specific medicines.
- PubMed (2008): Impact of symptoms experienced by varenicline users on tobacco treatment in a real world setting.
- MHRA: Package leaflet: Information for the patient.
- NIH: Benefit assessment of bupropion, cytisine, nicotine and varenicline for smoking cessation in severe tobacco dependence.
- Cancer Research UK (2024): NHS England offers an improved stop-smoking pill to help people quit.
- Pharmaceutical Journal (2025): Smoking cessation pill Champix returns to market four years after withdrawal over carcinogen.
- NIH (2022): Smoking: Learn More – Medication for quitting smoking.
- NICE (2025): Bupropion.
- FDA: Highlights of Prescribing Information.
- PubMed (2023): First Episode of Psychosis in the Context of Varenicline Treatment for Smoking Cessation.
- PubMed (2020): Varenicline, Smoking Cessation and Neuropsychiatric Adverse Events.
- EMC: Package leaflet: Information for the user.
- JAMA (2006): Varenicline, an α4β2 Nicotinic Acetylcholine Receptor Partial Agonist, vs Sustained-Release Bupropion and Placebo for Smoking Cessation.
- NHS: Cytisine.
- Wiley (2023): Evaluation of the effectiveness of cytisine for the treatment of smoking cessation: A systematic review and meta-analysis.
- EMC: Cytisine 1.5 mg tablets.
- JAMA (2021): Effect of Cytisine vs Varenicline on Smoking Cessation.
- National Centre for Smoking Cessation and Training: Cytisine.
- Cleveland Clinic: Bupropion Sustained-Release Tablets (Smoking Cessation).
- Mayo Clinic: Bupropion (oral route).
- CDC: How to Use Varenicline.
- NHS: Side effects of varenicline.
Authored By
Kate Latham
Medical Content WriterPublished on: 23/10/2025
Reviewed By
Mohamed Imran Lakhi
MPharm - Lead PharmacistReviewed on: 23/10/2025
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