Transdermal nicotine in smoking cessation and involvement of non-specific influences

The efficacy of a nicotine transdermal therapeutic system (TTS) (available size 10, 20 and 30 cm2; nicotine delivery rate = 0.7 mg/cm2/24 h) as an aid for smoking cessation, was evaluated in a randomized, single-blind, placebo-controlled, monocenter study using 160 heavy-smokers (> 20 cigarettes/day), male and female, who were divided into two matched parallel groups. The nicotine replacement treatment lasted for 3 months and was carried out according to the manufacturers recommendations. Abstinence was defined as smoking no cigarette during the last week of each month and COHb-levels < or = 1.2%. Efficacy was assessed using abstinence rates, withdrawal symptoms and cigarette consumption. Although at the commencement of the study all subjects expressed a high motivation to stop smoking, about a third were lost to follow-up at 4 weeks. This was attributed mainly to the lack of counselling and group dynamics. The greatest effect on smoking cessation and cigarette consumption was attributable to a non-specific aspect of treatment, i.e. the motivation to stop smoking on application of the first patch. On an intention-to-treat basis (all subjects), abstinence rates were 24% and 18% after 1 month, 24% and 14% after 2 months and 14% and 6% after 3 months for the nicotine-TTS and placebo-TTS, respectively. Nicotine-TTS was at least twice as effective as placebo in maintaining nicotine abstinence. The superiority of the nicotine-TTS was supported by the trend to a higher craving-for-cigarettes score and significantly higher blood COHb and cigarette consumption in the non-abstainers treated with placebo.