Airway sensory replacement combined with nicotine replacement for smoking cessation. A randomized, placebo-controlled trial using a citric acid inhaler.
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 < or = 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.