Quitting smoking with varenicline, week by week

Medically reviewed by Muhammad A Jalil, Superintendent Pharmacist (GPhC Reg No: 2236161)

Published 2026-08-22 · Clinically reviewed 2026-08-22 · Updated 2026-08-23

What varenicline does, the week-by-week plan UK prescribers use, side effects to expect and how to give a quit attempt its best chance of sticking.

Varenicline roughly triples your chance of quitting smoking compared with willpower alone, and it is the most effective single stop-smoking medicine available in the UK. It works best when you know the shape of the course in advance: you start the tablets one to two weeks before your quit date, step the dose up over the first eight days, and continue for twelve weeks — smoking is allowed in week one, cravings fade rather than vanish, and the strange vivid dreams are normal. Here is the whole course, week by week.

How varenicline works

Cigarette addiction runs on nicotine locking into receptors in the brain and triggering a dopamine reward. Varenicline occupies those same receptors and does two things at once: it stimulates them gently, taking the edge off craving and withdrawal, and it blocks nicotine from landing — so if you do smoke, the cigarette is strangely unrewarding. Smokers describe it as cigarettes "losing their point". That double action is why varenicline outperforms nicotine patches and gum in head-to-head trials, and why it returned to UK prescribing (as generic varenicline, after the branded product's long absence) with guidance recommending it as a first-line option.

The week-by-week plan

Week 1 — keep smoking, start the tablets. Days 1–3: 0.5 mg once daily. Days 4–7: 0.5 mg twice daily. The slow build lets your stomach adjust. Pick a quit date between day 8 and day 14 and tell people about it.

Week 2 — full dose, quit day. From day 8: 1 mg twice daily, morning and evening, with a full glass of water and ideally food. On your quit date, stop smoking completely — the receptors are now largely occupied, and most people find cigarettes taste flat if they lapse.

Weeks 2–4 — the hard yards. Withdrawal irritability and cue-driven cravings peak here, even with the tablets softening them. Cravings arrive in waves of a few minutes: have a plan for the wave (water, walking, the 4 Ds — delay, deep breathe, drink water, do something else). This is also when behavioural support earns its keep — combining varenicline with structured support roughly doubles success again versus tablets alone, and UK stop-smoking services are free.

Weeks 5–12 — consolidation. Cravings space out and weaken. Keep taking the tablets to the end of the twelve weeks even if you feel cured — stopping early is strongly linked with relapse. If you slipped and smoked in the early weeks, do not abandon the course; keep going and re-quit within it.

After week 12. Most people stop the tablets there. If you have quit but feel fragile, a second twelve-week course is licensed and sometimes prescribed to protect the gain.

Side effects, honestly

Nausea is the headline side effect — up to a third of people get some, usually mild and settling over weeks; taking each dose with food and water blunts it. Vivid, cinematic dreams and some sleep disturbance are common and oddly popular as anecdotes; taking the evening dose earlier (with the evening meal rather than at bedtime) helps. Headache, dry mouth and constipation appear on the list too.

Two sensible cautions. First, alcohol can feel stronger on varenicline — go carefully until you know your response. Second, any marked low mood or unusual behaviour change during a quit attempt deserves prompt medical advice; large trials have reassured on varenicline's psychiatric safety versus placebo, but quitting itself is a turbulent time and support matters. People with epilepsy, significant kidney impairment, or who are pregnant or breastfeeding need an individual discussion — pregnancy usually points to other options first.

If you are ready to set a quit date, you can check your eligibility for varenicline online — a UK clinician reviews your health background and, where suitable, prescribes the full course with the titration pack to start.

Stacking the odds

Set a real quit date in week one and treat it as fixed.
Take the free support. Local stop-smoking services and quitline coaching double down on the tablets' effect.
Clear the environment — bin cigarettes, lighters and ashtrays on quit eve; change the routines welded to smoking (coffee spot, smoking break timing).
Expect weight and mood wobbles — a few pounds and some irritability are normal physiology, not failure, and both are far kinder to your health than smoking.
If you relapse fully, wait, regroup, and go again — most successful quitters needed several attempts, and a previous varenicline course does not stop a future one working.

Frequently asked questions

Can I smoke while taking varenicline?

In week one, yes — that is by design, while the dose builds and the receptors fill. After your quit date the aim is zero, but a lapse is not a medical problem (the cigarette will mostly feel pointless); the mistake is letting a lapse cancel the attempt.

How does varenicline compare with patches, gum or vaping?

Trials place varenicline above single-form nicotine replacement and roughly level with — or slightly above — combination patches-plus-gum. E-cigarettes also outperform patches in UK trials and some people use them successfully; varenicline offers a medicine-based route with a defined end point, and unlike nicotine products it contains no nicotine at all.

What happens if I miss a dose?

Take it when you remember unless the next dose is close — never double up. Missing occasional doses will not sink the attempt, but erratic taking weakens the receptor blockade that makes cigarettes unrewarding, so build the doses into fixed routines like breakfast and dinner.

Do the tablets work for everyone?

No medicine does — around one in four to one in five smokers on varenicline with support are still smoke-free at a year, which sounds modest until you compare it with the 3–5% of cold-turkey attempts that last that long. If a course does not get you there, the next attempt can try a different combination.