Study	Reason for exclusion
Burstein 2006	RCT of tolerability and safety of varenicline in 24 elderly (≥ 65) smokers for 1 week. Not a cessation trial.
Chantix 2006	39 smokers randomised to NRT alone (17) or varenicline + NRT (22) for 12 days to test safety and side effects of co‐administration. 36% of combined group discontinued, compared with 6% of NRT alone group.
Cui 2012	Open‐label non‐randomised pre/post study of 36 HIV+ participants; all got varenicline, assessed at wks 12 and 24.
Dezee 2013	New for 2016 update. RCT in which all participants were given varenicline; intervention tested was in‐person vs internet counselling.
Dutra 2012	53 participants with schizophrenia given varenicline + CBT. Abstinence assessed at 12 weeks (end of treatment).
Ebbert 2009a	Open‐label, single‐arm Phase II study, for safety and efficacy of varenicline plus bupropion.
Ebbert 2009b	Cohort analysis of 104 participants on varenicline + NRT and 135 participants treated prior to release of varenicline (93% used NRT).
Ebbert 2014	New for 2016 update. RCT in which all participants were given varenicline; the intervention being tested was bupropion vs placebo. See also Hong 2011 NCT00492349
Falk 2014	Varenicline was used for alcohol reduction, not for smoking
Fatemi 2013 NCT01111149	New for 2016 update. 3‐arm RCT of varenicline, bupropion and placebo; only assessed to end of treatment (12 weeks).
Ferketich 2012	New for 2016 update. Pilot study of varenicline vs NRT; participants could choose their treatment; intervention being tested was the addition of a lung cancer screening programme.
Ferketich 2013	New for 2016 update. Safety of varenicline among smokers enrolled in the Lung HIV study. Participants could choose varenicline or NRT, and were only followed for 3 months.
Frye 2013	New for 2016 update. Small (9 participants) feasibility study in bipolar participants, open‐label, followed only until end of treatment (12 weeks).
Fucito 2011	RCT of 30 heavy‐drinking smokers, assigned to pre‐treatment varenicline or placebo, prior to 4 wks varenicline; primary outcome was effects on drinking behaviour, but smoking status at end of study (8 wks) was also measured.
Granatowicz 1976	Polish uncontrolled study of 1968 smokers, 71% taking cytisine, followed for 6m.
Gray 2012	New for 2016 update. Pilot study of varenicline vs bupropion in older adolescents; outcome was reduction rather than cessation, and participants were only followed for 3 months.
Hajek 2011	101 smokers randomised to preloaded varenicline or placebo; abstinence not measured beyond 12 weeks.
Hajek 2013	New for 2016 update. All were given varenicline, with the intervention tested being the addition of a NRT patch. Only followed to 3 months.
Hartwell 2014	Varenicline for drinking and smoking; smoking topography and pharmacogenetics rather than smoking cessation
Hawk 2012 NCT00835900	New for 2016 update. RCT of extended pre‐TQD varenicline vs standard regimen; all participants got varenicline, and were followed only until end of treatment (12 weeks).
Hong 2011 NCT00492349	New for 2016 update. Secondary analysis to Ebbert 2014, looking at depression in recipients of varenicline + bupropion vs varenicline alone
Hoogsteder 2014	New for 2016 update. All participants were given open‐label varenicline; the intervention being tested was the addition of NicVAX.
Hsueh 2014	New for 2016 update. Open‐label cohort study of smokers taking varenicline or NRT.
Jain 2014	New for 2016 update. RCT of smokeless tobacco users in India (to be covered in our review of interventions for smokeless tobacco).
Jennings 2014	New for 2016 update. The EUROACTION PLUS study; a complex nurse‐led intervention for smokers at high risk of CVD. Varenicline was a treatment option. Only followed to 16 weeks.
Jiménez‐Ruiz 2013	New for 2016 update. Cohort study of smokers not responding to standard varenicline dosage by 8 weeks treated with varenicline 3 mg/day in 2 Spanish smoking cessation clinics.
Kempe 1967	Bulgarian 1965 observational uncontrolled study of 30 male smokers given cytisine (Tabex) for 25 days and followed up for 6m.
Koegelenberg 2014	New for 2016 update. All participants took varenicline; the intervention being tested was the addition of NRT.
Maliszewski 1972	Polish uncontrolled study of 14 smokers on a 25‐day course of cytisine (Tabex); followed up for 2 wks.
Marakulin 1984	Russian trial of 620 smokers; no placebo, but autogenic training for control group. Follow‐up 6 wks
McColl 2008	RCT of varenicline's potential as an abuse drug in smokers and non‐smokers; not a smoking cessation trial.
McNaughton 2013	New for 2016 update. All participants received varenicline; the intervention being tested, as a relapse prevention aid, was interactive voice response phone calls
Metelitsa 1987	Russian uncontrolled study of 281 smokers, comparing anabasine hydrochloride, cytisine or a combination of both drugs, taken as biosoluble film on a paper or fabric patches. Followed for 6 ‐ 14m.
Mocking 2013	New for 2016 update. 7‐day administration of varenicline for emotional and cognitive processing in non‐smokers.
Mocking 2014	New for 2016 update. 7‐day administration of varenicline for cortisol levels, not for smoking cessation.
Monova 2004	Bulgarian RCT of 150 moderate+ smokers; investigators did not instruct participants to stop smoking, but monitored their smoking behaviour during and after a 25‐day course of cytisine (Tabex). Follow‐up was 60 days.
NCT00502216	New for 2016 update. Study of varenicline and naltrexone for tolerability and weight gain in smokers, not cessation.
NCT01308736	Outcome was 50% reduction in smoking, not abstinence (none succeeded in quitting completely).
NCT01806779	All participants got varenicline; the addition of bupropion was the intervention being tested.
Nollen 2011	RCT of 72 black smokers; all received varenicline, but half got extended counselling and half a single session. Cessation only measured to 3m endpoint.
Ostrovskaia 1994	Russian uncontrolled study of 74 smokers, comparing anabasin, cytisine or combination therapy, in film patches. (Relates to Metelitsa 4‐stage study). Followed for 6 ‐ 14m.
Park 2011	RCT of 49 smokers with lung cancer randomised to varenicline or placebo; Follow‐up only for 12 weeks to end of treatment.
Patterson 2010	New for 2016 update. Short‐term (3‐week) study of propensity to relapse with working memory deficits after 10 days of varenicline.
Paun 1968	Bulgarian controlled trial of cytisine (Tabex) (366 smokers) vs placebo (239 smokers) but followed only for 8 wks. Observational study of 230 cytisine‐users followed for 26 wks, but no comparator group.
Pfizer 2006	Phase II flexible‐dosing trial of varenicline in 312 participants. Treatment lasted 12 weeks, and cessation outcomes reported for continuous abstinence through weeks 9 ‐ 12.
Poling 2010	RCT of varenicline in 31 methadone‐maintained smokers; trial lasted 3m, and reduction was an outcome of interest (though 3m abstinence was reported).
Ramon 2014	New for 2016 update. RCT in which all participants received varenicline; intervention being tested was the addition of NRT.
Rose 2014	New for 2016 update. RCT of varenicline versus varenicline + bupropion, in smokers who had failed to quit on NRT. All got varenicline.
Schlienz 2014	New for 2016 update. 4 weeks treatment with varenicline; outcome was impact on behavioural economic indices, not smoking cessation.
Schmidt 1974	Non‐randomised trial of 16 smoking cessation preparations, including cytisine (Tabex) (200 smokers); participants allocated to treatment 'by chance', and followed up over 3m. Placebo group not directly matched to cytisine (Tabex) group.
Schnoll 2011	New for 2016 update. RCT of open‐label varenicline + counselling; intervention being tested was recruitment strategies, not smoking cessation.
Shim 2011	60 smokers with schizophrenia randomised to varenicline or placebo for 8 weeks; assessment at end of treatment, reduction but not abstinence rates reported.
Sicras‐Mainar 2010	Multicentre observational non‐randomised non‐controlled study.
Stapleton 2008	Non‐randomised trial of 412 attenders at a London smoking cessation clinic, choosing either NRT (single product or combination) or varenicline. NRT arm were historical controls. Effectiveness and safety were assessed separately in a subset of 111 participants receiving treatment for mental illness.
Stoyanov 1972	87 smokers (17 of them psychiatric patients); observational study with no comparator group and short but unstated length of follow‐up.
Swan 2010	All participants were given varenicline (treated as an included study for 2012 update).
Weiner 2011	9 smokers with schizophrenia randomised to varenicline or placebo; final assessment was at 12 weeks (end of treatment).
Zatonski 2006	Polish uncontrolled observational study of 342 smokers; at 12 months 13.8% abstinent.