IMPORTANCE OF BASE-LINE COTININE PLASMA VALUES IN SMOKING CESSATION -RESULTS FROM A DOUBLE-BLIND-STUDY WITH NICOTINE PATCH

Nicotine replacement by transdermal patches is more effective than pla cebo in smoking cessation, but has a low success rate after one year ( 9-18%). We tested whether this was attributed to insufficient nicotine replacement. We conducted a randomized trial to investigate the effec t on outcome of different doses of transdermal nicotine replacement af ter stratification according to base-line plasma cotinine values. Two hundred and ninety seven adult smokers were enrolled Those with baseli ne cotinine less than or equal to 250 ng . ml(-1) (low cotinine) were randomly assigned to placebo (LC-P) or to 15 mg 16 h nicotine patches (LC-15), and those with baseline cotinine >250 ng . mL(-1) (high cotin ine) were randomly assigned to 15 mg (HC-15) or 25 mg (HC-25) 16 h nic otine patches. Plasma nicotine and cotinine values, expired carbon mon oxide and withdrawal symptoms were measured at scheduled intervals dur ing treatment. Smokers in the LC-15 group had a significantly higher s uccess rate than placebo (28 vs 9%). Smokers with high baseline cotini ne had lower success rates, and a high dose of nicotine did not increa se success rate (HC-25 9% vs HC-15 11%). Subjects in the HC-15 group h ad the lowest percentage of nicotine replacement and a higher prevalen ce of withdrawal symptoms than the HC-25 group. Replacement was simila r in groups LC-15 and HC-25, but the success rate was significantly lo wer in HC-25 group, despite similar levels of withdrawal symptoms. We conclude that a higher success rate was obtained after one year in smo kers with low baseline plasma cotinine values. Determination of plasma cotinine values may be, thus, helpful in identifying smokers who coul d benefit from transdermal nicotine replacement.