Summary of controlled trials of cytisine for smoking cessation
| First author | Study design and quality* | Study population | Behavioural support | Length of follow-up | Main results | Confounders/ comments |
|---|---|---|---|---|---|---|
| Paun (1968) | Placebo-controlled trial (−) | Cytisine: N=366 Placebo: N=239 | Unclear | 8 weeks | Cytisine: 55% (n=202) Placebo: 33% (n=80) (p<0.001) | No validation of abstinence Non-randomised, results of 2 sites using drug compared with 3rd site using placebo |
| Scharfenberg (1971), Benndorf (1968), Benndorf 1968 | Randomised placebo-controlled trial (+) | Exclusions: hypertension, arteriosclerosis Cytisine: N=607 Placebo: N=607 | Initial session and follow-up 4–6 weeks after starting treatment | 4 weeks 6 months 2 years | Cytisine: 65% (n=395) Placebo: 41% (n=246) (p<0.001) Cytisine: 30% (n=185) Placebo: 16% (n=97) (p<0.001) Cytisine: 21% (n=127) Placebo: 13% (n=79) (p<0.001) | No validation of abstinence Two-year follow-up by mail with 66% response rate |
| Schmidt (1974) | Randomised placebo-controlled trial (+) | N=2470 smokers recruited via TV and newspaper ads Cytisine: N=250 Placebo: N=270 | Single information lecture | 4 weeks 3 months | Cytisine: 41% (n=103) Placebo: 31% (n=84) (p<0.05) Cytisine: 25% (n=68) Placebo: 21% (n=57) (NS) | No validation of abstinence All contacts by post, 74% response rate at 3 months |
| Marakulin (1984) | Controlled trial (−) | Autogenic training (AT): N=232 Autogenic training + cytisine: N=388 | Inpatient autogenic training treatment | 3 weeks | AT alone: 53% (n=123) AT+cystisine: 70.1% (n=272) (p<0.5) | No validation of abstinence Unclear allocation to groups No placebo |
| Monova (2004) | Randomised placebo-controlled trial (−) | Cytisine: N=75 Placebo: N=75 | 8 visits over 60 days to review smoking diary and for laboratory tests | 26 days | Cytisine: 37% (n=28) Placebo: 3% (n=2) (p<0.5) | Unclear whether double blind Collected urinary cotinine but unclear if used |
| Vinnikov (2008) | Randomised placebo-controlled trial (++) | Exclusions: Serious or unstable medical conditions Cytisine: N=85 Placebo: N=86 | ‘2 weeks screening and counselling’ followed by medication use | 8 weeks 6 months | Cytisine: 10.6% (n=9) Placebo: 5.8% (n=5) p=0.36 Cytisine: 10.6% (n=9) Placebo: 1.2% (n=1) p=0.01 | Russell Standard outcome CO validated |
| West (2011) | Randomised placebo-controlled trial (++) | Exclusions: Current psychiatric disorder Cytisine: N=370 Placebo: N=370 | Baseline visit, telephone calls on quit date and 1 week, a visit at 4 weeks | 6 month 12 months | Cytisine: 10.0% (n=37) Placebo: 3.5% (n=13) p<0.001 Cytisine: 8.4% (n=31) Placebo: 2.4% (n=9) p<0.001 | Russell Standard outcome CO validated |
*Quality ratings take into account study design and features highlighted in the column confounders/comments.