Cimetidine is a specific competitive
histamine H2-receptor antagonist which effectively inhibits gastric acid secretion and is advocated for the treatment of chronic peptic ulceration, haemorrhage from erosive
gastritis, and the control of gastric hypersecretion and peptic ulceration in the
Zollinger-Ellison syndrome. Placebo-controlled trials in outpatients have demonstrated its efficacy in promoting the healing of endoscopically diagnosed duodenal ulceration, during a period of 4 to 6 weeks, but its role in the treatment of
gastric ulcer is less clear. Preliminary evidence suggests that maintenance
therapy with
cimetidine reduces the rate of recurrence of
duodenal ulcer, but further studies are required to clarify its role in this situation and in the treatment of oesophagitis and acute gastrointestinal haemorrhage.
Cimetidine controls the peptic ulceration of
Zollinger-Ellison syndrome in most patients when given continuously for up to 2 years. Side-effects have generally been trivial and have very seldom necessitated withdrawal of
therapy except in the rare occurrence of gynaecomastia. The haematological abnormalities particularly
agranulocytosis, which lead to the withdrawal from clinical use of
metiamide, have not been reported with
cimetidine, except for 1 case of transient
neutropenia. The safety of long-term
cimetidine administration has yet to be determined.