Cytisin

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Cytisin

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Method of action: N-Cholinomimetic

Treatment option: Nicotine Dependence

Medically reviewed

Laura Arias

Last updated on 22/12/2025

This page provides general, reference-level information compiled from official medical sources. It is not a substitute for professional medical advice, diagnosis, or treatment. For decisions about your health, please consult a qualified healthcare professional.

Overview of Cytisin

Quick Facts

Property Description
Active ingredient Cytisine
Form Oral film-coated tablet
Pharmacological class Nicotinic acetylcholine receptor partial agonist
Common use Smoking cessation aid
Origin Natural alkaloid (Plant-derived)

What Type of Medicine is Cytisin?

Cytisin is a prescription-only medicine containing the single active substance Cytisine, which is used as a pharmacological aid for smoking cessation. This drug is classified as a nicotinic acetylcholine receptor partial agonist, which aligns with its classification for treating nicotine dependence.

This classification defines the fundamental action: Cytisine engages the same receptors in the nervous system as nicotine, primarily the alpha4beta2-nicotinic receptors, but only activates them partially. This partial agonism is considered a key mechanism for modulating nicotine pathways, providing a foundation for its use in tobacco dependence treatment.


Is Cytisine a Natural Alkaloid or Synthetic Compound?

The active ingredient, Cytisine (C11H14N2O), is a natural alkaloid found in plants, specifically derived from the seeds of the Cytisus or Laburnum genera, confirming its origin as a plant-derived quinolizidine derivative. This distinction from synthetic anti-smoking aids is a differentiating factor in its composition.

Cytisin is manufactured as a single active ingredient product and is formulated as an oral film-coated tablet. This oral dosage form is administered via the oral route of administration, and its presentation as a compact, coated tablet is common across several popular brands with the same active substance, which historically gained recognition in Eastern European markets.


What is the General Purpose of Cytisine Therapy?

The general therapeutic purpose of Cytisine therapy is to provide pharmacological assistance in the treatment of tobacco dependence to facilitate smoking cessation. Its partial agonist mechanism is crucial: it effectively mitigates the physical and psychological withdrawal symptoms experienced when quitting, while also diminishing the pleasurable reward associated with smoking. Cytisine serves as an aid for long-term smoking cessation. This mechanism supports the medicine's role as a treatment option for individuals who have made the commitment to stop using tobacco.

What side effects are possible with Cytisin?

Official Classification of Adverse Reactions

The possible side effects of Cytisin are documented in regulatory sources and categorized by the System-Organ Class ( SOC) they affect and their frequency of occurrence. These classifications reflect how government bodies formally organize the medicine’s safety profile.

Adverse reactions are most frequently observed in the Nervous System and the Gastrointestinal System.


Frequency Classification of Documented Effects

The following is a selection of effects categorized by frequency according to official prescribing information:

Classification Examples of Documented Effects
Very Common (1/10) Insomnia, Headache, Dry mouth, Diarrhoea
Common (1/100 to < 1/10) Dizziness, Irritability, Mood change, Appetite increase, Constipation, Fatigue
Uncommon (1/1,000 to < 1/100) Tachycardia, Hypertension, Nightmares

Time-Related and Population-Specific Safety Notes

The official safety documents note that most side effects are typically observed at the beginning of treatment and often subside with continued administration. This defines a time-related safety pattern.

Serious Adverse Reactions documented in official labeling for smoking cessation aids include the potential for suicidal ideation and behaviour, which is noted as a high-level safety consideration.

Safety Restrictions (Contraindications) explicitly limit the use of Cytisin. It is formally restricted in patients with a history of recent myocardial infarction, recent stroke, unstable angina, or clinically significant arrhythmias. Furthermore, the medicine is not recommended for use in older adults ( over 65) or in those with renal or hepatic impairment due to limited clinical experience in these populations. The regulatory documents state it is contraindicated in pregnancy and breastfeeding.

Overdose and Emergency Response

Overdose Scope

Element Official Regulatory Statement
Documented overdose presentations Manifestations of acute overdose are consistent with nicotine intoxication. Symptoms include nausea, vomiting, diarrhea, abdominal pain (especially upper abdomen), tachycardia (increased heart rate), dizziness, general weakness, mental confusion, mydriasis (enlargement of the pupils), and difficulty breathing.
Physiological systems affected Gastrointestinal (vomiting, diarrhea), Cardiovascular (tachycardia), Neurological (confusion, convulsions), and Respiratory (dyspnea, respiratory paralysis).
Dose-related or exposure-related factors Overdose is associated with the consumption of higher than prescribed doses. Ingestion of toxic doses poses a risk of respiratory paralysis.
Emergency-response statements The patient must discontinue taking the medicine and consult a doctor or ask for help at the nearest hospital immediately.
When immediate medical help is required Urgent medical intervention is required for suspected overdose or if severe symptoms such as convulsions or significant difficulty breathing occur. Urgent hospital treatment is likely to be needed.

Overdose Classifications (High-Level)

Element Official Regulatory Statement
Severity classification The potential for convulsions and respiratory paralysis classifies high-dose exposure as a severe and potentially life-threatening poisoning.
Overdose-context constraints Overdose management is limited to symptomatic and supportive treatment because no specific antidote is known.

Resulting Overdose Structure

Official overdose statements:

  • Overdose may present with a syndrome mirroring nicotine intoxication, including gastrointestinal disturbances, tachycardia, mental confusion, and general weakness.
  • The most serious outcomes documented include convulsions and the risk of respiratory paralysis.
  • Management is strictly symptomatic and supportive, utilizing measures such as gastric lavage, activated charcoal, and monitoring of respiration, heart rate, and blood pressure.

Connection to the overall overdose profile: Regulatory documents define the Cytisine overdose profile by listing severe, dose-related manifestations of nicotinic poisoning that directly impact the CNS and respiratory system. Since no specific antidote is known, the official guidance places an absolute requirement on the patient to seek urgent medical attention to receive mandated supportive care, continuous monitoring, and procedural interventions necessary to manage these potentially life-threatening symptoms.

Therapeutic Uses of Cytisin

What Cytisine Treats: Main Uses and Benefits

Cytisine is a pharmaceutical aid commonly used in the treatment of nicotine and tobacco dependence to facilitate smoking cessation. It is used for smoking cessation and reduction of nicotine cravings in adult smokers willing to stop smoking. Its therapeutic role is primarily relevant for providing pharmacological support during the challenging process of quitting. Cytisine is relevant for addressing conditions presenting with intense dependence and recurrent cravings.


Assisting with Nicotine Withdrawal and Cravings

This medicine is applied across domains where additional symptomatic support is needed to directly manage the acute nicotine withdrawal syndrome, which is a common barrier to successful quitting. It helps reduce the intensity and frequency of severe urges or cravings to smoke, while also easing the accompanying symptoms related to irritability and general restlessness. This core benefit assists with maintaining functional stability and contributes to improved comfort during the initial, acute phase of abstinence.


Supporting Long-Term Abstinence

Cytisine is relevant for managing symptoms that interfere with daily comfort for adult smokers across the severity spectrum, including those with moderate to severe dependence who have experienced prior unsuccessful attempts to quit. By providing effective pharmacological assistance, the medication is used to support the achievement and maintenance of long-term abstinence from tobacco, and provides supportive relief for those committed to a smoke-free life.


Quick Facts: Therapeutic Scope

Element Description (Safe Framing)
Symptom Focus Helps manage symptom clusters that may become intense or disruptive (cravings, irritability)
Condition Context Relevant in conditions characterized by periods of heightened symptoms (nicotine withdrawal)
Patient Benefit Provides supportive relief when symptoms interfere with routine activities, assisting with functional stability

Eligibility and Restrictions for Use

The eligibility for Cytisin use is determined by official regulatory classifications, which define approved populations, absolute prohibitions, and populations requiring caution or exclusion. The medicine is formally indicated for use in adults aged 18 to 65 years who are willing to stop smoking.


Contraindicated Populations

The medicine is contraindicated and must not be used by patients with known hypersensitivity to any component of the formulation. Absolute exclusions also apply to conditions connected with severe cardiovascular impairment, including recent myocardial infarction, recent stroke, unstable angina, or clinically significant arrhythmias. Cytisin is also contraindicated during pregnancy and breastfeeding, and women of childbearing potential must use highly effective contraception while on treatment.


Age and Condition Restrictions

Use is not recommended for individuals under 18 years of age or those over 65 years of age due to limited clinical experience in these populations. Similarly, the drug is not recommended for patients with renal (kidney) or hepatic (liver) impairment as safety and efficacy data have not been established. Caution is required when prescribing to patients with conditions such as hypertension, heart failure, diabetes, ulcers, or certain psychiatric disorders.

What should I know about interactions with other medicines?

Interactions with other medicines and products

Official regulatory documentation defines the interaction profile of Cytisine based on direct prohibitions, additive effects, and indirect metabolic changes.

Documented Interaction Constraints

Classification Interacting Substances/Context Regulatory Statement
Contraindicated Anti-tuberculosis drugs Co-administration is formally prohibited.
Pharmacodynamic Risk Nicotine-containing products Simultaneous use may result in aggravated adverse reactions of nicotine.
Indirect Effect CYP1A2 Substrates (e.g., Theophylline) Stopping smoking may increase plasma concentrations of these medicines, necessitating dosage adjustment.
Caution Advised Statins, Antihypertensives, Physostigmine, Galanthamine Caution is advised due to the possibility of increased side effects when co-administered.

Pharmacokinetic and Timing Considerations

Cytisine is primarily cleared via renal excretion of the unchanged substance, which results in a low risk for direct pharmacokinetic interactions mediated by hepatic CYP450 enzymes. The regulatory profile notes that the medicine can be taken with or without food. Due to a lack of clinical data regarding altered clearance and exposure, Cytisine is not recommended for use in individuals with pre-existing renal impairment or hepatic impairment.

Furthermore, women using systemically acting hormonal contraceptives should employ a second barrier method, as it is currently unknown whether Cytisine may reduce the contraceptive's effectiveness.

Mechanism of Action

Modulation by Partial Receptor Agonism

Cytisine acts as a partial agonist for the mathbfalpha4beta2-nicotinic acetylcholine receptors ( nAChRs) in the brain. This engagement generates a sub-maximal signal compared to nicotine, attenuating the neural dysregulation associated with the absence of a full agonist. This action modulates the neuronal hyperexcitability that occurs upon full agonist withdrawal, thereby promoting the maintenance of basal dopaminergic signaling.


Competitive Blockade of Nicotine Reinforcement

The molecule also utilizes competitive binding due to its high affinity for the same nAChRs. By physically occupying the receptor sites, Cytisine prevents the full agonist from binding and triggering the maximal response. This mechanism significantly diminishes the physiological reward signal (reinforcement) typically associated with full agonist binding, thereby constraining the excessive activation of the mesolimbic system.

Dosage and Administration Information

How to Use Cytisin

The general principle of using the active substance Cytisin is defined by a fixed-duration, 25-day course with a gradually decreasing daily dose.


Administration Guidelines

Cytisin is administered via the oral route using a 1.5 mg tablet. The tablet must be taken with a suitable amount of water but may be consumed with or without food.

The 25-Day Tapering Schedule

Use of the medicine follows a specific tapering schedule designed to reduce the daily dose and frequency across five distinct phases:

Treatment Phase Daily Dosing Frequency Max Tablets/Day
Days 1–3 1 tablet every 2 hours 6
Days 4–12 1 tablet every 2.5 hours 5
Days 13–16 1 tablet every 3 hours 4
Days 17–20 1 tablet every 5 hours 3
Days 21–25 1 to 2 tablets per day 2

Procedural Conditions and Constraints

The total treatment duration is 25 days, during which a critical procedural condition is imposed: complete cessation of smoking must occur no later than on the 5th day of the course. If a dose is forgotten, the instruction is to not take a double dose to compensate, but to continue with the next scheduled dose. Furthermore, use is not recommended in patients with renal or hepatic impairment, or in adults over 65 years, due to limited clinical experience in these specific populations.

This structured regimen represents the standard application of the treatment.

Recent Clinical Evidence

Research evidence / Overview of studies for Cytisin

The Core Research: Studies for Smoking Cessation

The primary body of research for Cytisine involves clinical trials and meta-analyses exploring the compound in studies of adult smokers who wish to quit tobacco. The research examined Randomized Controlled Trials (RCTs), a common study design used in this research area.

In these trials, research explored the outcomes observed with Cytisine compared to an inactive pill, known as a placebo. The main focus of these studies was to measure continuous abstinence from smoking, typically verified by physical tests at long-term follow-up points, generally 6 months or 12 months after starting the study. Research also explored how patients reported their experiences, looking at outcomes related to physical discomfort and outcomes capturing phases of heightened symptom activity, such as cravings.

Findings describe patterns observed in the studies where higher rates of continuous abstinence were measured in the groups receiving Cytisine compared to groups receiving placebo. However, certainty remains low for some of the comparisons.


The Comparative Research Landscape

Research has explored how Cytisine compares to other established treatments used in smoking cessation studies, including Nicotine Replacement Therapy (NRT). The studies observed the continuous abstinence rates across these different study groups.

Comparative evidence is lacking for many direct comparisons against other prescription compounds, meaning the data available may not clearly establish a definitive difference in outcomes. Comparative evidence involving indirect analyses contributes to the broader evidence landscape but is associated with methodological limitations.


Long-Term Evidence and Research Gaps

Researchers designed studies to observe how outcomes persisted over time, with key studies monitoring participants for at least 6 months and up to 12 months. While these follow-up periods are critical for assessing sustained abstinence, there is limited information for long-term outcomes beyond the one-year mark in the synthesized data.

Also, the majority of research has focused on the general adult smoking population. As a reminder, the results apply only to the populations studied in the RCTs, and data for certain groups remain insufficient or limited.

Key Studies & References

  1. WHO Anatomical Therapeutic Chemical (ATC) Classification System - N07BA04 (Cytisine)

Frequently Asked Questions (FAQ)

Common questions about Cytisin (FAQ)

Q: Is Cytisin available over the counter, or is it prescription-only?

A: Cytisin is typically classified as a prescription medicine in many regions. This regulatory classification means that the drug is dispensed following consultation with a healthcare professional.

Q: What is the recommended storage temperature for Cytisin tablets?

A: Official documentation specifies that Cytisin should be stored at a temperature below 25°C (77°F). Furthermore, the tablets must be kept in their original packaging to protect them from moisture until they are ready to be used.

Q: What should be done if someone accidentally takes too much Cytisin?

A: Official guidance recommends immediately seeking emergency medical attention for a suspected overdose. Symptoms documented in regulatory information may include feelings of nausea and vomiting, or a rapid, irregular heartbeat.

Q: Are there any common interactions between Cytisin and antibiotics?

A: The body primarily removes Cytisin through the kidneys as the unchanged substance. This method of clearance is associated with a low risk of interaction with medicines, such as antibiotics, via the liver's primary enzyme systems. Specific interactions should be confirmed with official documentation.

Q: How long does the effect of one dose of Cytisin last in the body?

A: The substance is described as having a short half-life, often cited around 4.8 hours. This characteristic is consistent with the established administration schedule outlined in the product information.

Q: Can Cytisin affect my ability to drive or operate machinery?

A: Official safety information notes that Cytisin may cause some patients to feel dizzy or drowsy. Documentation states that individuals should exercise caution and assess how the medicine affects them before driving or operating machinery.

Q: Do you need a specific diagnosis to be eligible for Cytisin?

A: Cytisin is officially authorized for use in the context of smoking cessation in adults. Eligibility criteria described in regulatory summaries focus on the individual being an adult who uses tobacco and wishes to quit.

Q: Is Cytisin considered a controlled substance in the US or UK?

A: No, Cytisin is generally not classified as a controlled substance in the United Kingdom or the United States. It is often regulated as a prescription drug, but it does not fall under the same legal scheduling as highly controlled substances.

Q: Can Cytisin be used by people with a history of anxiety or depression?

A: Official safety information acknowledges the possibility of mood changes and notes the high-level safety consideration for suicidal ideation documented for smoking cessation aids. Some regulatory documents describe the need for caution if a person has a history of psychiatric disorders.

Q: What should be done if a user experiences a severe allergic reaction to Cytisin?

A: If any signs of a severe allergic reaction or hypersensitivity (e.g., swelling, difficulty breathing) occur, official safety guidance notes that the medicine should be stopped immediately, and emergency medical care should be sought.

Q: Are there any specific official warnings for people with stomach ulcers using Cytisin?

A: Some official documentation notes that caution is advised if a person has an exacerbated peptic ulcer (stomach ulcer) before using the product. This condition is described as requiring professional consideration.

Q: What is the molecular formula of Cytisin?

A: Cytisin is a plant-derived compound, and its molecular formula is officially documented as mathbfC11H14N2O. This formula describes the precise ratio and types of atoms that compose the molecule.

Q: What are the common reasons why a person might have to stop taking Cytisin?

A: The treatment course may be discontinued if a person experiences a severe adverse reaction (such as an allergic response). It may also be stopped if a new or worsened health condition that is listed as a contraindication (for instance, a recent heart event) develops.

Q: Are there any restrictions on foods or beverages while using Cytisin?

A: Official documentation generally states that the medicine can be taken with or without food. Primary regulatory sources do not universally list any specific, broad dietary restrictions required during the course.

Q: What happens if Cytisin is taken by someone who does not need it?

A: Official regulatory warnings state that simultaneous use of Cytisin with nicotine-containing products may result in aggravated adverse reactions associated with nicotine.

Q: Is it true that Cytisin has been used historically for a long time?

A: Yes, historical and regulatory context describes Cytisin as the world’s oldest smoking cessation aid. It has been in use in certain regions internationally for over 50 years.

Q: Can Cytisin be crushed or split, or must it be swallowed whole?

A: The product is administered via the oral route using a tablet designed to be taken with water. Regulatory documents detail the administration, but they do not typically authorize or specify the crushing or splitting of the tablet.

Q: Is there a generic version of Cytisin available?

A: Cytisin is the name of the active compound, and it is sold under various brand names internationally. Whether a specific formulation is considered a generic version depends on the regulatory approval and specific market in that country.

Q: Does Cytisin interact with any common pain relievers?

A: Since Cytisin is mainly cleared by the kidneys rather than the liver, it is associated with a low risk of direct interaction with many other medicines that rely on the liver’s major enzyme system. Specific interactions with pain relievers are not broadly listed in official documents.

Q: Why is Cytisin sometimes mentioned alongside nicotine replacement therapies?

A: Official research and guidelines often mention Cytisin alongside nicotine replacement therapies (NRT) because they are both established treatments utilized in smoking cessation studies and are often subjects of comparative research in this therapeutic area.

Q: Does taking Cytisin require any special dietary restrictions?

A: Official documents state that the medicine can be consumed with or without food. Generally, no specific, broad dietary restrictions are universally listed in the primary regulatory information.

Q: How does the structure of Cytisin differ from nicotine?

A: Although Cytisin and nicotine interact with the same brain receptors, they are structurally distinct compounds. Cytisin's official molecular formula is mathbfC11H14N2O, while nicotine's is mathbfC10H14N2.

Q: What is the typical starting dose mentioned in informational documents?

A: Informational documents describe the course beginning with the established highest frequency of administration, which is then gradually reduced over the treatment period, as defined in the official tapering schedule.

Q: How is the quality of Cytisin ensured by manufacturers?

A: Regulatory agencies, such as the EMA and MHRA, require manufacturers to comply with strict protocols, such as Good Manufacturing Practices (GMP), to ensure quality. These practices verify the purity, identity, and consistency of the drug substance.

Q: What is the official classification of Cytisin's safety profile?

A: Overall, Cytisin is generally described in research summaries as being well tolerated. Its safety profile is noted as comparable to other smoking cessation treatments, with most side effects being mild and temporary.

Q: Does Cytisin cause weight changes?

A: Official safety documents list appetite increase as a common side effect of Cytisin. However, the documentation does not contain a specific or formal statement classifying weight gain or loss as a primary, commonly observed adverse reaction.

Q: What official information is available about Cytisin use during pregnancy?

A: There is currently limited official data on the effects of Cytisin use during pregnancy in humans. Due to this lack of data, the use of Cytisin during pregnancy is generally limited according to official guidelines.

Q: What age groups are eligible to use Cytisin according to official guidelines?

A: Official guidelines state that use is not recommended in adults over 65 years due to limited clinical experience in that population. Eligibility typically begins in adulthood, but the specific minimum age for treatment should be confirmed with regulatory documentation.

Q: Are there any known differences in how Cytisin affects men vs. women?

A: One specific note for women is that those using systemically acting hormonal contraceptives should employ a second barrier method, as it is currently unknown if Cytisin may reduce the contraceptive's effectiveness. Other broad differences are not generally specified in core safety documentation.

Q: How is Cytisin eliminated from the body?

A: Cytisin is primarily cleared via renal excretion (through the kidneys) as the unchanged substance. This mechanism of elimination contributes to the drug’s low risk for direct interactions mediated by the liver’s enzyme systems.

How should Cytisin be stored and disposed of?

Storage and Disposal Requirements for Cytisine

The storage of cytisine film-coated tablets is defined by specific regulatory requirements to maintain product stability.

Official Storage Conditions

Item Requirement Entity
Storage Temperature Store below 25°C
Environmental Protection Keep in the original package to protect from moisture and light
Child Safety Keep out of the sight and reach of children

Cytisine must be kept in its original package at a temperature below 25°C. This is necessary to shield the tablets from moisture and light, which can affect the product's quality. Given that cytisine is a potent alkaloid, storing the medicine out of the sight and reach of children is mandatory.

Disposal Instructions

Unused or expired cytisine must not be thrown away via wastewater or household waste. Patients are instructed to ask their pharmacist how to throw away medicines no longer used, ensuring proper handling of pharmaceutical waste.

Attention! Always consult to a doctor or pharmacist before using pills or medicines.

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