Cytisine side effects - what goes away on its own and when to stop the course

Side effects of cytisine (Desmoxan, Tabex, Recigar) appear most often in the first days of the course, when you take the most tablets. While taking Desmoxan or Recigar, at least 1 in 10 people have a dry mouth, nausea, abdominal pain, sleep disturbances with nightmares, a headache or a faster heartbeat. These complaints are usually mild or moderate and ease during treatment. Some of them may also be caused by nicotine withdrawal itself. From 6% to 15.5% of patients stopped the course because of side effects, and in controlled trials this proportion was similar to that in the placebo groups. Information on how often individual symptoms occur differs between products. Some symptoms mean you need to stop taking the medicine and consult a doctor or pharmacist.

In brief

• Dry mouth, nausea, upper abdominal pain, sleep disturbances, headache, irritability, anxiety and a faster pulse are very common side effects of Desmoxan tablets and Recigar. Constipation, diarrhoea, vomiting, dizziness, raised blood pressure and rash are classified differently: as very common for Desmoxan and as common for Recigar.
• Most complaints occur at the start of the course and ease as it goes on. Irritability, anxiety and insomnia are also symptoms of nicotine withdrawal, which are strongest in the first week without cigarettes.
• If you miss a tablet, do not take a double dose. Without consulting a doctor or pharmacist, do not change when you take the medicine or the number of doses, and do not use nicotine patches or gum on top of it.
• If you have symptoms resembling nicotine poisoning, a symptom not listed in the leaflet, or low mood with suicidal thoughts, you need to stop taking the medicine and contact a doctor.

What side effects can cytisine cause, and how common are they?

The most common side effects of cytisine are dry mouth, nausea, upper abdominal pain, sleep disturbances, headache, irritability, anxiety, a faster heartbeat and increased appetite. For Desmoxan tablets and Recigar, these fall into the very common category.

Very common means at least 1 in 10 people, common 1 to 10 in 100 people, and uncommon 1 to 10 in 1000 people. Instead of these categories, the SmPCs for Tabex and Desmoxan capsules give percentages from clinical trials, and for many symptoms they give a range of values rather than a single figure.

The table brings together selected symptoms from three Polish summaries of product characteristics (SmPCs): Desmoxan tablets (1), Recigar tablets (2) and Tabex (3). The percentages for Tabex are the same as for Desmoxan capsules (4).

Less common side effects of Desmoxan and Recigar, occurring in 1 to 10 in 1000 people, include watery eyes, shortness of breath, increased sweating, excessive salivation, reduced sex drive and raised liver enzymes (aminotransferases).

Why does side effect information differ between cytisine products?

Constipation, diarrhoea, vomiting, dizziness and rash are listed as very common side effects for Desmoxan tablets but as common for Recigar. Raised blood pressure is described as very common for Desmoxan tablets and Recigar Active oral solution (5), as common for Recigar tablets, and it occurred in 7% of patients taking Tabex. These data do not come from a direct comparison of the products, so they cannot be used to conclude that any one of them causes milder side effects.

When do cytisine side effects go away?

Most side effects occur at the start of treatment and gradually ease during the course.

You take the most tablets, up to 6 a day, on days 1-3, and from day 21 you take only 1 or 2 tablets a day. Dosing on the following days of the course is described in our article on the 25-day cytisine course.

In a 2023 Cochrane review (6), serious adverse events were reported about as often with cytisine as with a placebo (3 studies, 3781 participants). The authors considered this result to be of low certainty, and the studies did not provide data on serious side effects affecting mental health or the heart. If any of the symptoms that require stopping the course appears, contact a doctor, even on the second day of treatment, instead of waiting for the symptom to go away.

Is a symptom caused by cytisine, nicotine withdrawal or too much nicotine?

The same complaints during the course can have three sources: the effect of cytisine, nicotine withdrawal after quitting smoking, and too much nicotine in someone who is still smoking. Some symptoms on the list of side effects may be caused by stopping smoking rather than by the medicine.

In a review of 120 papers on tobacco withdrawal (7), the author lists anger, anxiety, low mood, difficulty concentrating, impatience, insomnia and restlessness as withdrawal symptoms confirmed in studies. These symptoms are strongest in the first week without cigarettes and last from 2 to 4 weeks. The author considered constipation, cough, dizziness, more frequent dreams and mouth ulcers to be possible effects of withdrawal, and sleepiness and fatigue to be unrelated to it.

The last column is a clue, not a diagnosis. In the Warsaw study involving 740 smokers, gastrointestinal complaints were reported 5.7 percentage points more often with cytisine than with a placebo (8). In a New Zealand study involving 1310 people, participants taking cytisine reported nausea, vomiting and sleep disturbances more often than those using nicotine patches and gum (9).

How can you tell what caused a symptom during a cytisine course?

1. When did the symptom start? If the symptom started before you stopped smoking, it is less likely to be caused by nicotine withdrawal. The timing of a symptom alone does not establish its cause.
2. Are you smoking or using another nicotine product at this time? If so, the symptoms may be due to the stronger effect of nicotine.
3. Does the symptom persist after the last tablet? The level of cytisine in the blood falls by half after about 4 hours on average, and 64% of the dose is excreted in the urine within a day. A symptom that lasts for weeks after the end of the course is therefore hard to attribute to the medicine. Nicotine withdrawal symptoms usually last a few weeks, and bouts of nicotine cravings can keep coming back long afterwards. We describe this in our article on quitting smoking day by day.

What happens if you smoke during a cytisine course?

Smoking during a cytisine course can make the side effects of nicotine worse. This applies to Desmoxan, Recigar and Tabex. During treatment with Recigar, you should not smoke or use other nicotine products.

You need to stop smoking cigarettes by day 5 of the course at the latest, and if you take Desmoxan capsules, you should start cutting down on cigarettes from day 1. Symptoms of an overdose of cytisine itself are similar to those of nicotine poisoning: feeling unwell, nausea, vomiting, a fast heart rate, fluctuating blood pressure, breathing and vision problems, and seizures. If even one of these symptoms appears while you are taking Desmoxan tablets, Recigar or Tabex, you need to stop taking the medicine and contact a doctor or pharmacist. If such symptoms appear after smoking a cigarette or using an e-cigarette or a nicotine pouch, it is sensible to do the same.

What are the most common side effects of cytisine like?

Gastrointestinal complaints are the most common group of cytisine side effects. For Desmoxan tablets, sleep disturbances, dry mouth, a faster pulse and raised blood pressure are also very common.

Does cytisine cause nightmares and insomnia?

Sleep disturbances during the course can include insomnia, sleepiness, drowsiness, strange dreams and nightmares. In the studies cited for Tabex, sleep disturbances were reported by 1% to 21% of participants (3). More frequent dreams can also result from nicotine withdrawal, and insomnia is a confirmed withdrawal symptom, so in the first week after quitting, both the medicine and nicotine withdrawal can disturb your sleep at the same time.

Taking the last tablet of the day earlier than scheduled, without moving the other doses, shortens the interval since the previous dose. Such a change needs to be agreed with a doctor or pharmacist.

Does cytisine cause nausea, abdominal pain and constipation?

Yes, gastrointestinal complaints are the most common group of cytisine side effects. Cytisine is used with caution in people with stomach or duodenal ulcers and gastro-oesophageal reflux disease. If you have one of these conditions and your heartburn or upper abdominal pain gets worse during the course, tell your doctor. Vomiting with nausea and a fast heartbeat resembles the symptoms of an overdose, which mean you need to stop taking the medicine. Constipation can be caused by both the medicine and nicotine withdrawal.

Does cytisine cause a dry mouth?

In the studies cited for Tabex, 35% of participants reported a dry mouth (3). Changes in taste and a burning tongue can also occur during the course. During the day, you can sip water or chew nicotine-free gum.

Does cytisine speed up the heart and raise blood pressure?

A fast heart rate is a very common side effect of Desmoxan and Recigar. In the data for Tabex, the proportion of trial participants with this symptom ranged from less than 1% to 14% (3). Cytisine is used with caution in coronary heart disease, heart failure and high blood pressure. It is not used at all after a recent heart attack, in unstable angina or in clinically significant heart rhythm disorders. A person with high blood pressure who has a blood pressure monitor at home can measure their blood pressure during the course and write down the results for their doctor.

Coffee also affects heart rate and sleep. In a German study of 12 people who smoked at least 20 cigarettes a day (10), after quitting smoking the participants' bodies cleared caffeine 36% more slowly, and the difference appeared within a few days. The same amount of coffee you drank before quitting may therefore have a stronger effect.

How should you deal with cytisine side effects?

On your own, you can sip water, cut down on coffee and write down your symptoms. Without consulting a doctor or pharmacist, do not change the dosing schedule or the doses of other medicines, and do not use extra nicotine.

What can you do yourself during a cytisine course?

• You can take the tablets with water and also sip water to ease a dry mouth.
• You can cut down on coffee, especially in the afternoon.
• You can keep a short diary, noting the day of the course, the time you took the tablet, any symptom and whether you smoked a cigarette that day. With such a record, it is easier to talk to a doctor and to tell the effects of the medicine apart from withdrawal symptoms.
• From day 5 of the course, do not smoke cigarettes or use e-cigarettes or nicotine pouches.

What should you not change in a cytisine course without consulting a doctor?

• The intervals between doses. A fixed dosing schedule applies: in the first days, you take 1 tablet every 2 hours, and at the end of the course 1-2 tablets a day.
• The dose after a missed tablet. If you miss a tablet of Desmoxan or Recigar, do not take a double dose.
• The maximum daily dose. On days 1 to 3, this is 6 tablets, and after that 5, 4, 3 and 2 tablets a day in turn.
• Extra nicotine. Nicotine patches, gum or sprays used during the course can make the side effects of nicotine worse.
• The doses of other medicines. After you stop smoking, the body breaks down some medicines more slowly. Slower breakdown of theophylline, tacrine, clozapine and ropinirole may matter for treatment. Levels of imipramine, olanzapine, clomipramine and fluvoxamine may also rise, although there are no data to confirm this. The dose is changed by the doctor who prescribed the medicine, so you need to tell them in advance that you are quitting smoking.

It is easiest to assess whether other medicines need a dose change before starting the course. In the 3-month nicotine dependence treatment plan, in the medical interview, the doctor asks about your medical conditions and the medicines you take, and issues an e-prescription for a medicine chosen on the basis of that interview. In the app, you get a reminder to take every dose and access to a diary.

When should you stop a cytisine course and contact a doctor?

You need to stop the cytisine course and contact a doctor or pharmacist if you have symptoms resembling nicotine poisoning, a symptom not listed in the leaflet or low mood with suicidal thoughts, and if you become pregnant.

• Feeling unwell, nausea with vomiting, a fast heart rate, fluctuating blood pressure, breathing or vision problems, seizures. These are symptoms of a cytisine overdose, similar to those of nicotine poisoning. Shortness of breath and seizures require urgent medical help.
• A symptom that is not listed in the leaflet. Tell a doctor or pharmacist about any such symptom. If you are taking Desmoxan tablets, Recigar or Tabex, you then need to stop taking the medicine; this recommendation appears in the overdose section of the leaflets.
• Low mood with suicidal thoughts. Low mood, rarely with suicidal thoughts or a suicide attempt, can be a symptom of nicotine withdrawal, and quitting smoking can make depression and other mental illnesses worse. If you have thoughts of taking your own life, do not wait for your next appointment: talk to a doctor or seek urgent help that same day, and tell someone close to you.
• Chest pain, palpitations with feeling faint or fainting, sudden weakness in an arm or leg, or speech problems. Cytisine is not used in unstable angina, significant heart rhythm disorders or after a recent stroke, so such a symptom during the course needs an urgent assessment by a doctor.
• Shortness of breath, wheezing or swelling after taking the medicine. Hypersensitivity to the medicine is a contraindication. The sodium metabisulfite contained in Recigar Active rarely causes severe hypersensitivity reactions and bronchospasm.
• Pregnancy. Cytisine is contraindicated in pregnancy and while breastfeeding.

The recommendations on stopping the course differ between products. With Desmoxan capsules (11), you need to stop the medicine and contact a doctor if you have any of the side effects listed in the leaflet, including dry mouth or a change in appetite. With Desmoxan tablets (12), Recigar and Tabex, you need to stop taking the medicine if you have symptoms of an overdose or a symptom not listed in the leaflet. Follow the recommendations in the leaflet for the product you are taking. If a symptom does not need urgent help but does not ease after a few days, decide together with a doctor or pharmacist whether to continue the course.

This article does not replace a medical consultation.

Frequently asked questions

How long do cytisine side effects last?

Cytisine side effects appear mainly at the start of the course and ease over time. In the first days, they overlap with nicotine withdrawal symptoms, which are strongest in the first week and usually last from 2 to 4 weeks. Cytisine is quickly eliminated from the body, so a symptom that does not go away, or gets worse, long after the last tablet is worth discussing with a doctor.

Does cytisine make you gain weight?

Cytisine can contribute to weight gain: increased appetite and weight gain are among the very common side effects of Desmoxan and Recigar. In the studies cited for Tabex, increased appetite occurred in 47% and weight gain in 21% of participants (3). According to the US National Cancer Institute (13), increased appetite is also a typical symptom of nicotine withdrawal. Our article on weight gain after quitting smoking explains how to limit weight gain without going back to cigarettes.

Can you drive during a cytisine course?

You can drive during a course of cytisine. Desmoxan and Tabex do not affect the ability to drive, and Recigar has no or negligible influence on it. However, dizziness and sleepiness can occur during treatment. If you feel dizzy or have trouble concentrating in the first days of the course, it is wiser to wait until the symptoms pass before driving.

Can you start a cytisine course again after stopping it?

If the first course of Desmoxan, Recigar or Tabex did not have a satisfactory effect, another one can be started after a break of 2-3 months. If the course was stopped because of side effects, it is worth discussing with a doctor which symptoms you had before starting again, because a different medicine may be needed. Our article on why cytisine sometimes does not work explains what to do when the medicine has not helped.

Sources

1. Charakterystyka Produktu Leczniczego Desmoxan 1,5 mg, tabletki (zmiana tekstu 31.10.2025). Rejestr Produktów Leczniczych
2. Charakterystyka Produktu Leczniczego Recigar 1,5 mg, tabletki powlekane. Rejestr Produktów Leczniczych
3. Charakterystyka Produktu Leczniczego Tabex 1,5 mg, tabletki powlekane. Rejestr Produktów Leczniczych
4. Charakterystyka Produktu Leczniczego Desmoxan 1,5 mg, kapsułki twarde. Rejestr Produktów Leczniczych
5. Charakterystyka Produktu Leczniczego Recigar Active 1,5 mg/dawkę, roztwór doustny. Rejestr Produktów Leczniczych
6. Livingstone-Banks J, Fanshawe TR, Thomas KH et al. Nicotine receptor partial agonists for smoking cessation. Cochrane Database Syst Rev. 2023;5(5):CD006103. PMID 37142273, DOI
7. Hughes JR. Effects of abstinence from tobacco: valid symptoms and time course. Nicotine Tob Res. 2007;9(3):315-327. PMID 17365764, DOI
8. West R, Zatonski W, Cedzynska M et al. Placebo-controlled trial of cytisine for smoking cessation. N Engl J Med. 2011;365(13):1193-1200. PMID 21991893, DOI
9. Walker N, Howe C, Glover M et al. Cytisine versus nicotine for smoking cessation. N Engl J Med. 2014;371(25):2353-2362. PMID 25517706, DOI
10. Faber MS, Fuhr U. Time response of cytochrome P450 1A2 activity on cessation of heavy smoking. Clin Pharmacol Ther. 2004;76(2):178-184. PMID 15289794, DOI
11. Ulotka dla pacjenta Desmoxan 1,5 mg, kapsułki twarde. Rejestr Produktów Leczniczych
12. Ulotka dla pacjenta Desmoxan 1,5 mg, tabletki. Rejestr Produktów Leczniczych
13. National Cancer Institute. Handling Nicotine Withdrawal and Triggers When You Decide To Quit Tobacco. cancer.gov