Placebo-controlled trial of cytisine for smoking cessation.


This single-center, double-blind, placebo controlled trial found that treatment with cytisine for 25 days was significantly more effective than placebo for smoking cessation. Although a 12-month abstinence rate of 8.4% is relatively low, it was triple the rate of the placebo group, and the minimal counseling and follow up were meant to mimic real world clinical scenarios. Because of its lower cost, cytisine may be a useful component in smoking cessation efforts.


  • N=740 adult smokers, randomized to receive minimal counseling (to simulate normal clinical treatment) and 25 days of:
    • Cytisine (n=370)
    • Placebo (n=370)
  • Medication regimen started with six tablets per day (taken every 2 hours), and tapered down to two tablets per day by the end of the 25-day treatment. Target quit day was the fifth day of medication treatment.
  • Setting: One site: a smoking-cessation clinic in Warsaw, Poland.
  • Follow up: telephone calls during treatment, and at 6 and 12 months after treatment, with clinic visits for those claiming abstinence.
  • Primary outcome: smoking abstinence for 12 months after treatment, verified with carbon monoxide concentration in exhaled breath.
  • Secondary outcome: abstinence for 6 months.


  • Rate of 12-month abstinence (P<0.001):
    • 8.4% (31/370) for cytisine
    • 2.4% (9/370) for placebo
  • Rate of 6-month abstinence (P<0.001):
    • 10.0% (37/370) for cytisine
    • 3.5% (13/370) for placebo
  • Cytisine group reported significantly more gastrointestinal adverse events than the placebo group.


West R, Zatonski W, Cedzynska M, et al. Placebo-controlled trial of cytisine for smoking cessation. N Engl J Med. 2011;365(13):1193-1200. doi:10.1056/NEJMoa1102035.

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