Background:
Hookah tobacco smoking has increased worldwide yet there is little evidence for the efficacy of pharmacological therapies to achieve abstinence among hookah smokers. Our objective was to assess the efficacy of varenicline when added to behavioural support for hookah tobacco cessation.

Methods:
In 2016, we conducted a double-blind, placebo controlled, randomized trial in Pakistan enrolling 510 daily hookah users who were willing to quit. All participants received behavioural support and either varenicline or placebo at randomisation. The primary outcome was 25 weeks continuous abstinence biochemically verified by a carbon monoxide level of < 10 ppm.

Results:
Among the 510 trial participants, 429 (84%) were male and 81 (16%) female; 249 (49%) smoked only hookah and 261 (51%) smoked both hookah and cigarettes. 21 participants withdrew from treatment mainly due to adverse events. We recently completed the last follow-up (25 weeks) on May 23^rd, 2017 with a 93% (475/510) retention rate. The data will remain blinded for treatment allocation until the primary analysis is complete.


[Trial Flow Chart]



Conclusions:
We will report our primary outcome results at the '17th World conference on Tobacco or Health' in Cape Town for the first ever trial of varenicline among hookah smokers. The findings of this pharmacotherapy trial will have major implications for knowledge translation, practice and policy regarding hookah tobacco use.