Champix side effects and precautions

Champix is a prescription drug because it can pose a contraindication with certain medications and health conditions. This means some smokers are unsuited to Champix. Some users may also experience mild side effects, but serious side effects in users are rare.

Side effects

Champix is a well-tolerated and clinically-proven stop smoking medicine that is available in several dosages. If you experience unwanted side effects your dosages may be reduced on advice from a doctor.

The standard dose for smokers starting out with Champix is just 0.5mg for the first few days, followed by 0.5 mg twice daily and then 1mg twice daily for the remainder of the twelve-week course.

If you have a health condition or intolerance the 0.5 mg dose can be extended for the whole course. Ask your doctor for advice. You will be prescribed the correct dose during your consultation. This is why it is important to always obtain Champix with a prescription.

Very common side effects include an inflamed nose and throat, abnormal dreams, difficulty sleeping, headaches and nausea. People who have experienced mild side effects report that they can pass after a period of time, and can disappear completely once their body has become used to the new medication.

Some quitters say the benefits of using prescription Champix and going smoke –free outweigh the initial mild discomforts, but if side effects do not dissipate, or they worsen, speak to your doctor.

Common side effects include:

  • Chest infection
  • Inflammation of the sinuses
  • Increased weight
  • Decreased appetite or increased appetite
  • Sleepiness
  • Dizziness
  • Changes in the way things taste
  • Shortness of breath or a cough
  • Heartburn
  • Vomiting
  • Constipation, diarrhoea, feeling bloated, abdominal pain
  • Toothache
  • Indigestion, flatulence
  • Dry mouth
  • Skin rash, itching
  • Joint ache, muscle ache, back pain
  • Chest pain
  • Tiredness

Uncommon side effects include restlessness, mood swings, sex drive changes, fungal infection, palpitations, raised blood pressure and eye pain. See the medical insert that is included with Champix for a full list of uncommon side effects.

Rarely users may experience an allergic reaction which includes a swollen mouth, tongue and lips or hives, and there is some evidence that users of Champix users may experience changes in behaviour including poor judgement, suicidal thoughts and depression. If you experience these contact a doctor immediately.


Champix is used successfully by many smokers but there are some people for whom it is not suitable.

You should not take Champix if you are pregnant because traces of the drug can pass to the unborn child and via breast milk.
Do not take Champix if you are under 18 because it has not been tested sufficiently on this age group and may cause problems in those that are still growing and developing.

Other stop smoking therapies should be used with caution and only on the advice of your doctor.

You must tell your doctor if you have experienced:

  • Cardiovascular disorder symptoms including heart attack, stroke or raised blood pressure.
  • A history or mental illness, low mood, depression, bipolar disorder, or anxiety. Some people may develop unexpected changes in behaviour and mood.
  • Seizures, convulsions and fits.
  • An allergy to any of the ingredients.
  • Kidney problems.
  • Haemodialysis treatment.
  • Heart disease or other cardiovascular condition.

You must tell your doctor as soon as possible if you have unexpected changes in behaviour or mood. People who quit smoking may experience emotional and mood disturbances without taking Champix as it can be a side of effect of nicotine withdrawal. If you are in any doubt or notice serious mood changes speak to your doctor.


When you stop smoking your body undergoes a variety of changes, most of those are for the better as you clear tar, nicotine and chemicals from your system, however, this process may also change how some medicines work, even if you do not use Champix. Certain medicines may remain in your system for a longer time when you quit smoking, increasing the levels in your bloodstream, and the potential for side effects.

If you take, have taken or plan to take other medicines, you must tell your prescribing doctor, dentist or pharmacist, so they can adjust any dosages if necessary. This includes herbal remedies, over the counter medicines, and diet pills as well as prescription medicines.

Quitting cigarettes may change the actions of:

  • Some asthma medications
  • Insulin
  • Some benzodiazepines
  • Some beta-blockers
  • Theophylline used to treat breathing problems
  • Tricyclic antidepressants
  • Warfarin used to treat blood clotting
  • If you have severe kidney disease avoid taking cimetidine as this may cause increased blood levels of Champix

This is not a definitive list of contraindications and your doctor will advise whether you should take Champix with your current medication. You may still be able to take Champix with monitoring, a medication dosage change, or a reduced dose of Champix instead. If in doubt, you should consult your doctor or pharmacist.

There have been reports that Champix interacts with alcohol to increase the intoxicating effects. There is no scientific study to prove this, but it’s recommended you avoid alcohol when you are using Champix, not least because it may break your resolve to quit smoking.

Champix is clinically proven to minimise cravings and reduce the pleasure associated with smoking cigarettes, however, you may not tolerate the drug, or be unsuitable. Speak to your doctor if you are interested in Champix to help quit smoking. If you are not able to take it there are other options available such as nicotine replacement therapies, and support services.