Randomized, controlled trial of clonidine for smoking cessation in a primary care setting.

Clonidine hydrochloride has been reported to reduce tobacco withdrawal symptoms and facilitate smoking cessation. We enrolled 185 subjects, 92 receiving clonidine and 93 receiving placebo, in a randomized, double-blind study of clonidine for smoking cessation in a primary care setting. Clonidine had no demonstrable effect on withdrawal (8 of 11 measures favoring placebo). At 4 weeks, 17 (18%) subjects receiving clonidine had quit compared with 13 (14%) receiving placebo (chi 2 = 0.7; 90% confidence interval of benefit from clonidine, -4% to 13%). At 4 weeks, the mean number of cigarettes smoked was 17.7 for those receiving clonidine and 17.5 for those receiving placebo (t = 0.1; 90% confidence interval of benefit from clonidine, -4.1 to 3.7 cigarettes per day). These results provide little support for a beneficial effect of clonidine on tobacco withdrawal symptoms, quitting, or smoking reduction in a primary care setting.