Cytisine: The Quit-Smoking Drug Most Americans Cannot Get

There is a smoking cessation drug that works about as well as varenicline, costs a fraction of the price, has been used by millions of people in Eastern Europe since the 1960s, and is not available in the United States. Cytisine is a partial agonist at nicotinic acetylcholine receptors, the same mechanism as varenicline. A 2023 trial of 1,452 participants found it non-inferior to varenicline for six-month continuous abstinence [1]. A course of cytisine costs roughly $20-30 in countries where it is available. A course of varenicline costs several hundred dollars in the US without insurance.

What cytisine is

Cytisine is a naturally occurring alkaloid found in the seeds of the laburnum tree (Cytisus laburnum). It binds to the alpha-4-beta-2 nicotinic acetylcholine receptors, the same receptor subtype that nicotine and varenicline target. Like varenicline, it acts as a partial agonist: it provides enough receptor stimulation to reduce withdrawal symptoms and cravings while simultaneously blocking nicotine from producing its full rewarding effect [5].

The pharmacological similarity between cytisine and varenicline is not coincidental. Varenicline was developed in the 1990s partly by studying cytisine’s binding properties and then designing a synthetic molecule with optimized receptor affinity and pharmacokinetics. In a sense, varenicline is the pharmaceutical refinement of cytisine, engineered for longer half-life and more consistent receptor occupancy. Cytisine is the original, and it has decades of real-world use behind it.

It has been marketed in Eastern Europe as Tabex since 1964, initially in Bulgaria and later across central and eastern European countries including Poland, Russia and the Baltic states. Millions of courses have been dispensed over that period. The safety profile from decades of use is broadly reassuring, though the pharmacovigilance systems in those markets during the earlier decades were less rigorous than current Western standards, which is one reason Western regulators have required modern trial data before considering approval.

The trial evidence

The evidence base has strengthened substantially in recent years, with trials published in the New England Journal of Medicine providing the kind of data that regulatory agencies outside Eastern Europe require.

CESSATE trial (2023). This was the pivotal study. A randomized, active-controlled, non-inferiority trial of 1,452 participants in New Zealand compared cytisine (given over 25 days) to varenicline (given over 12 weeks). The primary endpoint was continuous abstinence from weeks 9 to 24. Cytisine met the non-inferiority criterion: its quit rates were statistically not worse than varenicline’s [1]. This is the key finding for cytisine’s future: it performs comparably to the strongest existing cessation medication in a well-designed, adequately powered trial.

The trial also collected safety data in a population not previously exposed to cytisine in large numbers. Adverse event rates were comparable between groups, with nausea being the most common side effect in both arms.

Cytisine vs. NRT (2014). A trial of 1,310 participants, also from New Zealand, compared cytisine to nicotine replacement therapy. Cytisine was superior to NRT at the one-month follow-up, with similar rates at six months [2]. This places cytisine at least comparable to NRT in sustained effectiveness, with a possible advantage in early abstinence.

Placebo-controlled trials. Earlier trials established that cytisine significantly outperforms placebo, roughly doubling quit rates in a pattern consistent with the effect sizes seen for NRT and bupropion [3]. These trials were smaller and conducted primarily in Eastern European populations, but the direction and magnitude of the effect are consistent with the later, larger studies.

Network meta-analysis. A 2013 Cochrane network meta-analysis included cytisine alongside varenicline, NRT and bupropion and found it positioned favorably in the efficacy ranking [4], though the evidence available at that time was limited compared to the other agents.

How cytisine compares

Method	Six-month quit rate	Treatment duration	Approximate cost per course	Prescription required	Evidence volume
Cytisine	Comparable to varenicline	25 days	$20-30 (where available)	Varies by country	Growing; pivotal trial published 2023
Varenicline	~25-30% (vs. ~10% placebo)	12 weeks	$300-600 (US without insurance)	Yes	39 Cochrane trials
Combination NRT	~15-25% higher than single NRT	8-12 weeks	$100-200	No	Multiple trials
Single NRT	~15-20%	8-12 weeks	$50-150	No	136+ Cochrane trials
Bupropion	~15-20%	7-12 weeks	$50-200 (US)	Yes	46 Cochrane trials

The cost difference is the most striking feature of this comparison. Cytisine is derived from a commonly available plant, has been off-patent for decades, and requires a shorter treatment course (25 days compared to 12 weeks for varenicline or 8-12 weeks for NRT). The drug itself is inexpensive to manufacture. If cost is a barrier to cessation pharmacotherapy, and it frequently is, particularly in low-income populations and in countries without universal cessation coverage, cytisine could substantially change the accessibility equation.

The shorter treatment course is also worth noting. A 25-day course presents a lower adherence burden than a 12-week course. Whether this is an advantage or a disadvantage in practice depends on the individual: some people may benefit from the shorter commitment, while others may need longer pharmacological coverage through the high-relapse period that extends well past the first month.

Why it is not available in the US

Cytisine was developed and marketed in the Soviet bloc during a period when Western pharmaceutical regulatory pathways did not apply. No company submitted it for FDA approval during the decades it was in use in Eastern Europe, because the commercial incentive was limited: the drug was cheap, off-patent, and the FDA approval process requires expensive clinical trials and regulatory submissions that are difficult to justify for a low-margin product.

This is a structural problem in pharmaceutical economics. The FDA approval process is designed for novel, patented drugs whose commercial potential justifies the investment. Cytisine is the opposite: a cheap, old drug with no patent protection and limited profit margin. The result is that an effective cessation medication has been available to Eastern European smokers for decades while being unavailable in the market where smokers arguably need it most.

Regulatory submissions are now in progress, driven partly by the CESSATE trial data and partly by organizations focused on affordable cessation access. The timeline for potential US availability is uncertain. In some countries outside the US, including Australia, New Zealand and parts of the EU, cytisine has become available more recently following independent regulatory reviews.

Side effects

The side effect profile is similar to varenicline, which is expected given the similar mechanism. Nausea is the most common adverse effect, followed by headache, upper abdominal discomfort and other gastrointestinal symptoms. In the CESSATE trial, adverse event rates were comparable between cytisine and varenicline groups [1], which is consistent with the shared pharmacology: both drugs act at the same receptor, so the mechanism-related side effects are similar.

The shorter treatment course (25 days vs. 12 weeks) means the total duration of side effect exposure is substantially less than with varenicline. For people who find the nausea manageable but unpleasant, knowing it lasts three to four weeks rather than three months may affect adherence.

No serious safety signals have emerged from the modern trials or from the decades of post-marketing use in Eastern Europe, though the pharmacovigilance data from the earlier decades is less rigorous than modern Western standards. The psychiatric safety question that dominated the varenicline conversation has not been a prominent concern for cytisine, partly because cytisine was widely used before the post-marketing surveillance systems that flagged the varenicline concern were in place, and partly because the CESSATE trial did not find a signal.

What this means if you’re deciding

If you are in the US, cytisine is not currently available to you through standard channels. The methods with the strongest accessible evidence remain varenicline, combination NRT and bupropion.

If you are in a country where cytisine is available (parts of Europe, New Zealand, Australia), it is a reasonable first-line option, particularly if cost is a factor. The CESSATE trial provides strong evidence that it performs comparably to varenicline at a fraction of the cost and with a shorter treatment course [1].

For smokers with COPD, cytisine’s mechanism (partial nicotinic agonist) is the same as varenicline, which has dedicated trial evidence in COPD populations. Direct COPD-specific cytisine trials are limited, but the pharmacological similarity is close enough that the evidence for varenicline in COPD is reasonably transferable. Where cytisine is available and affordable, it is a reasonable option for this population, with the same caveat that applies to all cessation methods: using the highest-efficacy method available is the most protective approach when lung function is at stake.

Open questions

Whether cytisine will receive FDA approval and when remains the primary open question for the US market. The commercial pathway is unusual: the drug is too cheap to generate the margins that typically fund regulatory submissions, which means the approval effort depends on non-traditional stakeholders, academic groups, public health organizations and governments interested in affordable cessation.

Whether cytisine can be effectively combined with NRT, as varenicline has been studied in combination, is not established. Whether the 25-day treatment course is sufficient for heavy smokers who may need longer pharmacological coverage through the relapse-prone period is also not settled; some practitioners in countries where cytisine is available prescribe a second course for people at high relapse risk.

The most important open question is arguably about access rather than efficacy. The efficacy question has been answered by the CESSATE trial. The question of how to make an effective, cheap cessation drug available in the markets where it is most needed is a policy problem, not a scientific one.

A doctor or pharmacist can help choose the right approach for your health history. The Quitline (1-800-QUIT-NOW) provides free coaching and can sometimes supply NRT.