Smoking impairs therapeutic gastric inhibition.

Cigarette smoking reversed the inhibition of nocturnal gastric secretion produced by the H2-receptor antagonists cimetidine and ranitidine and by the phenothiazine derivative LM 24056. As a consequence of smoking, nocturnal secretion of acid increased by 91.5% and of pepsin by an average of 59% when compared with control studies when patients did not smoke. The inhibition of pentagastrin-stimulated gastric secretion produced by cimetidine or poldine was not affected by cigarette smoking. Since control of nocturnal secretion may be important in promoting ulcer healing and maintenance of remission, patients receiving antisecretory drugs should be advised not to smoke after having taken their nocturnal dose of the drug.