Study objective: This study was conducted to determine if the combination of airway sensory replacement and nicotine replacement improves 10-week smoking abstinence rates over nicotine replacement alone.
Design: Double-blind, randomized, placebo-controlled trial.
Setting: Outpatient research clinic.
Participants: One hundred healthy volunteers who smoked at least one pack of cigarettes per day and desired to quit smoking.
Interventions: Subjects received either citric acid (n=41) or lactose placebo (n=59) inhalers to cope with smoking urges for 10 weeks. All subjects received self-help materials and nicotine patches for 6 weeks. Return visits were at weeks 1, 4, 6, and 10. Abstinence was defined as zero cigarettes smoked since the quit date verified by exhaled carbon monoxide ≤8 ppm at all return visits. Inhaler effects were measured by a standardized questionnaire.
Measurements and results: The primary outcome of continuous abstinence at the end of the 10-week treatment period was 19.5% (95% confidence interval [CI]=7.4 to 31.6%) for the citric acid group vs 6.8% (95% CI=0.4 to 13.2%) for the lactose group (p=0.05). Relief from craving and short-term abstinence increased as airway sensations from the inhaler also increased. Abstinence at 10 weeks for subjects receiving strong airway sensations from the inhalers was 33.3% (95%CI=14.5 to 52.1%). At 6 months, there was no difference in abstinence between the treatment groups (0% vs 5.1%, p=0.20).
Conclusions: When combined with the nicotine patch, the citric acid inhaler improved 10-week smoking abstinence over lactose inhaler. The combination of airway sensory replacement and nicotine replacement may prove beneficial for smoking cessation.