Cimetidine suppression of nocturnal gastric secretion in active duodenal ulcer.

Nocturnal pain and gastric hypersecretion are common in duodenal ulcer. Therefore, we investigated the antisecretory effects of a new H2-receptor antagonist, cimetidine, in 200-, 300- or 400-mg doses, taken orally at bedtime. The 200-mg dose did not cause a statistically significant change in nocturnal (midnight to 7 a.m.) acid output and had only a borderline effect on pH. However, the 300-mg and 400-mg doses significantly (P less than 0.001) lowered acid output and increased (P less than 0.01) intragastric pH. All doses caused substantial decreases in secretory volume output. After a 400-mg dose, half the patients remained anacidic for eight hours. Dose-related increases of drug blood levels were observed and correlated with the degree and duration of inhibition of acid output. Serum gastrin levels were unaffected. Cimetidine appears to be a potent inhibitor of nocturnal gastric secretion.