In a double-blind study, 19 adults received bedtime doses of either 150
mg of doxepin hydrochloride (N = 9) or placebo (N = 10). After 3 weeks the
subjects were instructed to stop smoking and continue taking medication for
4 additional weeks. Cessation was reported by all nine doxepin subjects 1
week after cessation and by seven doxepin subjects 9 weeks after cessation.
One placebo subject reported cessation. Cotinine assays generally confirmed
cessation but were subject to interpretation. Doxepin assays suggested that
the precessation level was associated with cessation. Further studies with
larger samples and extended follow-up are needed to determine the
reliability of these results.