General Health · Medication Guide
Varenicline in Thailand
What varenicline is, how well it works for quitting smoking, its side effects, and where its supply stands in Thailand after the 2021 recall. Reviewed by a licensed physician at a MOPH-registered men's health clinic.
- Standard course: 12 weeks
- Prescription only · ordered per patient
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Medically reviewed by Dr. Noppon Arunkajohnsak (Win)
Menscape Clinic
Last reviewed
11 July 2026
2.3×
Quit odds vs placebo
high-certainty Cochrane evidence, 41 trials³
12
Weeks per course
with an optional 12-week extension¹
1 wk
Before your quit date
you start the tablets while still smoking¹
2006
First approved
by the US FDA; two decades of use¹
Key takeaways
Varenicline is a prescription tablet for quitting smoking. It works on the brain's nicotine receptors, easing withdrawal while making cigarettes less rewarding.
In the largest smoking-cessation trial ever run (EAGLES, 8,144 smokers), varenicline outperformed bupropion, the nicotine patch, and placebo.
Global supply has been unstable since a 2021 impurity recall of the originator product. Availability in Thailand is intermittent; Menscape does not hold it in stock and confirms supply per patient.
Nausea affects roughly 1 in 3 users, and anyone with a psychiatric history needs monitoring. A doctor decides whether it is right for you.
01
What varenicline is & how it works
Varenicline is an oral prescription medicine for smoking cessation. It was designed specifically for quitting: it is a partial agonist at the α4β2 nicotinic acetylcholine receptor, the receptor nicotine binds to when you smoke.
That dual action is what makes it different from patches or gum. It gently stimulates the receptor, which takes the edge off cravings and withdrawal. At the same time it occupies the receptor, so if you do smoke, the cigarette delivers less of its usual reward. Most people notice smoking starts to feel flat within the first weeks.
The standard course is 12 weeks, started about one week before a planned quit date, with the option of a second 12 weeks to protect the quit. Whether varenicline is the right tool, and whether it can currently be sourced in Thailand, is decided at a doctor consultation.
Nicotine drives the loop
Each cigarette hits α4β2 receptors in the brain and triggers a dopamine reward, reinforcing the habit.
Varenicline takes the seat
It binds the same receptors and stimulates them partially, easing withdrawal and cravings between cigarettes.¹
Cigarettes lose their kick
With the receptor occupied, nicotine from a lapse cigarette produces much less reward. Smoking feels flat.
You quit on a set date
Dosing steps up over week 1 (0.5 mg daily to 1 mg twice daily); the quit date is typically day 8, flexible up to day 35.¹
02
Getting varenicline in Thailand
Thai legal status & supply
Varenicline is a prescription-only medicine in Thailand, sold under brands such as Champix and historically dispensed through hospital smoking-cessation clinics. Since the originator's worldwide 2021 recall over a nitrosamine impurity, supply in Thailand has been intermittent.⁵
How to get it through Menscape
Menscape does not keep varenicline on the shelf. After a doctor consultation, the clinic checks current supply and orders it per patient if it can be sourced. If it cannot, the doctor prescribes an alternative quit plan the same visit.
Avoid grey-market sellers
Post-recall scarcity created a grey market of imported tablets sold online with no impurity testing and no accountable pharmacist. Given the recall was about a contaminant, buying unverified stock defeats the point. Use licensed channels only.
Prescription medicines in Thailand may only be dispensed by a licensed pharmacist or prescribed by a licensed physician under the Drug Act. Availability of individual products changes with Thai FDA registration and importer supply; the clinic verifies status at the time of consultation.⁶
03
Does it work? The evidence
Varenicline has the strongest evidence base of any single quit-smoking medicine. In the EAGLES trial, the largest smoking-cessation study run to date (8,144 smokers, with and without psychiatric conditions), 33.5% of people on varenicline stayed continuously abstinent through weeks 9–12, versus 22.6% on bupropion, 23.4% on the nicotine patch, and 12.5% on placebo.² A 2023 Cochrane review rates the evidence as high-certainty: varenicline more than doubles the chance of quitting compared with placebo.³
Two honest caveats. First, quit rates decline over time in every study arm; at six months roughly one in five varenicline users in EAGLES remained abstinent, which is still around double the placebo rate.² Second, tablets do not replace a plan: medication works best combined with counselling and a fixed quit date, and relapse after the course is common without follow-up.
33.5%
Varenicline
continuously abstinent, weeks 9–12
12.5%
Placebo
same measure, no active drug
EAGLES randomised controlled trial, 8,144 smokers, Anthenelli et al., Lancet 2016. Individual results vary.
04
Side effects & who shouldn't take it
Common side effects
Nausea is the big one, affecting roughly 30% of users; taking the tablet with food and a full glass of water helps, and it often settles. Vivid or unusual dreams, insomnia, headache and constipation are also common.¹
Mood & rare serious effects
Reports of mood changes led to a US boxed warning in 2009. EAGLES was run to test this: it found no significant increase in serious neuropsychiatric events versus placebo, and the warning was removed in 2016.²⁴ Doctors still monitor mood, especially with a psychiatric history. Seizures are rare; heart-safety reviews have been broadly reassuring but recent cardiac events should be flagged.
Not suitable for
Under-18s (efficacy not demonstrated), pregnancy unless clearly needed, and anyone with a previous serious reaction to varenicline. Severe kidney impairment requires a reduced dose, so kidney disease must be declared at consultation.¹
Interactions & warnings
Varenicline has few direct drug interactions, but alcohol can hit harder on it: increased intoxication and unusual behaviour have been reported, so cut back until you know your response.¹ Quitting smoking itself raises blood levels of some drugs (clozapine, olanzapine, theophylline, warfarin, caffeine), which may need dose adjustment. Combining with nicotine patches increases nausea.
05
Alternatives & combinations
OTC · first stop
Nicotine replacement
Patches, gum and lozenges are available in Thai pharmacies without prescription. They roughly increase quit odds by half, and combining a patch with gum works better than either alone. In EAGLES, varenicline outperformed the patch.
Oral · prescription
Bupropion
An oral prescription medicine that reduces cravings through a different mechanism. A realistic option when varenicline is unsuitable or cannot be sourced; not for anyone with a seizure history.
Behavioral · free
Counselling & the 1600 Quitline
Thailand runs a free national quitline on 1600. Structured support roughly doubles the effect of any medication, and medication plus counselling beats either alone in trials.
06
How prescription works at Menscape
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Book a consultation and set your quit date.
Message us on WhatsApp or LINE
Five minutes on your phone: cigarettes per day, past quit attempts, health history, current medications. PDPA-protected.
Doctor consultation
A licensed Thai physician reviews your case by video call or in clinic at Asoke, builds a quit plan with you, and decides whether varenicline is appropriate.
Supply check & prescription
Varenicline is not held in stock; if prescribed, the clinic verifies current availability and orders it for you. If it cannot be sourced, the doctor prescribes an alternative such as nicotine replacement or bupropion.
Follow-up through the course
Check-ins around your quit date and at weeks 4 and 12: side-effect review, dose adjustment if nausea is a problem, and a decision on the optional 12-week extension.
The doctor decides. Starting a conversation is not a commitment and does not guarantee a prescription. Varenicline is subject to a supply check; if it is not right for you or not available, your doctor will say so and plan an alternative.
Medically reviewed by
Dr. Noppon Arunkajohnsak (Win)
Menscape Clinic, Bangkok
“Most smokers I see have already tried cold turkey three or four times. Medication roughly doubles the odds of a quit sticking. Using it is not weakness; going in without a plan is what fails.”
- Reviewed
- 11 July 2026
- Next review
- January 2027
- Editorial standard
- Each guide is checked against the Thai FDA label and the primary literature, then reviewed by a licensed physician.
07
Frequently asked questions
Can I buy varenicline over the counter in Thailand?
No. Varenicline is a prescription-only medicine in Thailand. It must be prescribed by a licensed doctor and dispensed through a licensed pharmacy. Online sellers offering it without a prescription are illegal, and post-recall grey-market stock carries a real contamination risk.
Is varenicline still available after the 2021 recall?
Partially. The originator recalled the product worldwide in 2021 over a nitrosamine impurity, and supply has been patchy since; generic versions have returned in some markets. In Thailand availability is intermittent, which is why Menscape checks supply per patient rather than promising stock.
How does varenicline compare with nicotine patches or gum?
In the EAGLES head-to-head trial, 33.5% of varenicline users stayed abstinent through weeks 9–12 versus 23.4% on the nicotine patch. Patches and gum are still worthwhile, are easier to get in Thailand, and can be a doctor's first recommendation when varenicline cannot be sourced.
Will it make me depressed or change my personality?
EAGLES was designed to answer exactly this in 8,144 smokers, including people with psychiatric conditions. It found no significant increase in serious neuropsychiatric side effects versus placebo, and the US boxed warning was removed in 2016. Doctors still monitor mood, so mention any psychiatric history at your consultation.
When do I actually stop smoking after starting the tablets?
You keep smoking at first. The usual plan is to start varenicline one week before a fixed quit date, so the drug reaches full effect as you stop. A flexible approach, quitting anywhere between days 8 and 35, is also on the label and works comparably.
What can I do about the nausea?
Take each dose with food and a full glass of water. Nausea affects roughly 30% of users, is usually mild to moderate, and often fades over the first weeks. If it does not, the doctor can halve the dose, which most people tolerate well.
Can I drink alcohol while taking varenicline?
Be careful at first. Some users report getting drunk faster, and unusual or aggressive behaviour after drinking has been reported. Cut back on alcohol until you know how varenicline affects you, and mention heavy drinking to your doctor.
What happens if I relapse after the 12 weeks?
Relapse is common and is not a personal failure; most successful quitters needed several attempts. The label allows a second 12-week course for people who quit, and a repeat course later is also an option. Your doctor will adjust the plan rather than write you off.
08
References
1. U.S. FDA. Chantix® (varenicline) prescribing information. Pfizer. Accessed July 2026.
2. Anthenelli RM, et al. Neuropsychiatric safety and efficacy of varenicline, bupropion, and nicotine patch in smokers with and without psychiatric disorders (EAGLES): a randomised, double-blind, placebo-controlled trial. Lancet. 2016;387(10037):2507-2520.
3. Livingstone-Banks J, et al. Nicotine receptor partial agonists for smoking cessation. Cochrane Database Syst Rev. 2023.
4. U.S. FDA Drug Safety Communication: FDA revises description of mental health side effects of the stop-smoking medicines Chantix (varenicline) and Zyban (bupropion). December 2016.
5. U.S. FDA. Pfizer voluntary recall of Chantix (varenicline) tablets due to N-nitroso-varenicline content. 2021.
6. Thai Food and Drug Administration — drug registration database, ndi.fda.moph.go.th. Accessed July 2026.
This guide is educational information, not medical advice. Varenicline is a prescription medicine that must be prescribed and monitored by a licensed physician, and its availability in Thailand is subject to supply.
This guide is part of the Menscape general-health library
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