How it works
Cytisine is a plant-based alkaloid that acts as a partial agonist at the α4β2 nicotinic acetylcholine receptor subtype in the brain — the same receptor subtype through which nicotine exerts its addictive effects. In the ventral tegmental area of the midbrain, α4β2 receptors on dopaminergic neurones control dopamine release into the nucleus accumbens, a core pathway of reward and reinforcement. By partially stimulating these receptors, cytisine reduces craving and withdrawal symptoms while simultaneously occupying the receptor to blunt the reinforcing effect of nicotine if smoking continues [PMID 37432430, PMCID PMC10336611]. The traditional 25-day regimen, using 1.5 mg tablets up to six times daily at the start then tapering down, was shown to be superior to placebo in a double-blind randomised trial (n=740, Poland). In that trial, 12-month continuous abstinence was 8.4% for cytisine versus 2.4% for placebo (relative risk 3.4). A larger open-label trial in New Zealand (n=1310) found 25 days of cytisine more effective than 8 weeks of nicotine replacement therapy at 6 months. A more recent phase 3 trial — ORCA-2, NCT04576949, published in JAMA 2023 — tested a novel 3 mg three-times-daily regimen given for 6 or 12 weeks versus placebo in 810 adults across 17 US sites. The 6-week course produced 25.3% verified continuous abstinence at end of treatment versus 4.4% for placebo (OR 8.0; 95% CI 3.9–16.3); the 12-week course produced 21.1% abstinence sustained to 24 weeks versus 4.8% for placebo (OR 5.3; 95% CI 2.8–11.1). No drug-related serious adverse events occurred [PMID 37432430, PMCID PMC10336611]. Cytisine has a mean elimination half-life of about 4.8 hours, which supports three-times-daily dosing in the newer schedules and explains why the traditional 25-day taper requires frequent administration. It is excreted largely unchanged in the urine. Hepatic or renal impairment were exclusion criteria in the major trials, so safety data in those populations are limited. Cytisine is not approved by the FDA but is authorised as a cessation medicine in several European countries and as a natural health product in Canada [PMID 37432430, PMCID PMC10336611].How to use
The course has two conditions that hold throughout it — the pack schedule, and the quit date.Follow the supplied 1.5 mg pack in order
Take tablets with water at the intervals printed on the pack.
Stop smoking no later than day 5
Choose the quit date before or by day 5 of the course.
Dose schedule
Days 1–3: one tablet every 2 hours
Days 1–3: one tablet every 2 hours
Take up to 6 tablets per day while reducing smoking and preparing to stop.
Days 4–12: one every 2.5 hours
Days 4–12: one every 2.5 hours
Take up to 5 tablets per day, and stop smoking no later than day 5.
Days 13–20: continue the taper
Days 13–20: continue the taper
Days 13–16 use one tablet every 3 hours, up to 4 daily. Days 17–20 use one every 5 hours, up to 3 daily.
Days 21–25: one or two daily
Days 21–25: one or two daily
Complete the final taper exactly as labelled. If the attempt is unsuccessful, stop the medicine and discuss when another attempt is appropriate rather than restarting immediately.
What has been reported
Contact your doctor if
- Chest pain, fainting, stroke symptoms, a sustained abnormal heartbeat, or a severe allergic reaction — seek urgent care
- Severe mood change, thoughts of self-harm, or symptoms that make continued treatment unsafe
- You cannot stop smoking by day 5, used nicotine throughout treatment, missed several timed doses, or want to restart a course
Storage
Keep in the original package, away from moisture and direct heat, and out of children’s reach. Follow the temperature limit on your pack and do not use it after the expiry date.What to expect
Cytisine partly stimulates nicotine receptors to reduce craving while nicotine use stops. The structured 25-day course and behavioural support can improve the chance of quitting, but results vary. Follow the exact pack schedule, use a firm quit date, and review an unsuccessful attempt with your doctor before repeating treatment.Who it is not suitable for
The consultation screens for medical conditions that make cytisine unsuitable. Tell the doctor about any heart condition, history of seizures, severe kidney or liver disease, or pregnancy or breastfeeding before starting treatment.Common questions
Can I drink alcohol while taking cytisine?
Can I drink alcohol while taking cytisine?
The product information does not list a specific interaction with alcohol. However, alcohol can weaken resolve during a quit attempt and may worsen side effects such as dizziness. Discuss your alcohol use with the prescribing doctor.
What if I cannot stop smoking by day 5?
What if I cannot stop smoking by day 5?
If you cannot stop smoking by day 5, used nicotine throughout treatment, or missed several timed doses, stop the medicine and discuss with your doctor when another attempt is appropriate. Do not restart immediately.
How does cytisine compare with varenicline?
How does cytisine compare with varenicline?
Both medicines partly stimulate nicotine receptors to reduce craving. Cytisine uses a 25-day taper whereas varenicline uses a different schedule. A doctor can discuss which approach may suit you better. See the varenicline guide.
Can I use nicotine replacement products alongside cytisine?
Can I use nicotine replacement products alongside cytisine?
The course is designed to stop nicotine entirely by day 5. Continued use of nicotine during treatment can worsen adverse effects. Do not continue smoking or using nicotine products unless a clinician has explicitly advised a plan.
What should I do if I miss a dose?
What should I do if I miss a dose?
Take the missed tablet as soon as you remember, then continue with the next scheduled dose. Do not double a dose to catch up. If you miss several doses, message the medical team for advice.
Are the side effects from cytisine or from nicotine withdrawal?
Are the side effects from cytisine or from nicotine withdrawal?
Some effects — irritability, anxiety, low mood, poor concentration and craving — may reflect nicotine withdrawal rather than the medicine. Digestive symptoms, sleep disturbance and vivid dreams are more likely from the medicine. Review the whole pattern with your doctor.