Influence of chronic omeprazole treatment on gastric endocrine function

Abstract

The influence of a 4-week treatment with the substituted benzimidazole omeprazole (20 mg daily) or placebo on gastric endocrine function was tested in healthy male volunteers. Compared with placebo-treated subjects basal serum gastrin levels were slightly but significantly increased after treatment with omeprazole from 10 to 22 pg/ml (medians; P less than 0.05) but returned to pretreatment values after 2 weeks recovery (9 pg/ml). Antral gastrin tissue concentration increased and was still elevated after recovery; however, antral gastrin concentrations also increased in placebo controls, and increments immediately after cessation of omeprazole treatment (2.58 micrograms/g; median) were not significantly over control values (1.92 micrograms/g; P greater than 0.1). Postprandial gastrin release, basal and food-stimulated insulin release, antral somatostatin concentration, and volume densities of antral G and D cells were unaffected. It is concluded that, due to incomplete inhibition of gastric acid secretion at the omeprazole dose studied, only slight effects on the endocrine stomach are to be expected after 4 weeks of administration of omeprazole.

Omeprazole: Long-Term Safety

“…Four to eight weeks' treatment with 20-90 mg omeprazole daily significantly increased basal serum gas trin levels in different groups of subjects [2,[27][28][29]. In most cases, these increases in plasma gastrin are moderate due to a feed back response to acid inhibition as in animal studies.…”

Clinical Significance of Hypergastrinaemia: Relevance to Gastrin Monitoring During Omeprazole Therapy

“…43]. but the lower end of this range was reached in only I out of 30 patients with an intact stomach who were treated with omeprazole for 6-36 months [28]. Furthermore, pernicious anaemia had been diagnosed for a mean of 10.6 years before gas tric ECL-cell carcinoids were found in 5 out of 123 patients [II].…”

Risks of Therapeutic Achlorhydria

“…In man, increases are usually two-to three-fold (123,124). Unfortunately, the gastric inhibitory effects of omeprazole, and the circulating levels of gastrin, cannot be easily interpreted since the drug does not exert a graded dose-related effect on either of these indices of gastric function.…”

“…Thus it has been shown that omeprazole exerts what is almost an 'all-or-none' inhibitory effect on gastric secretion and gastrin release in man. For example, the currently 'recommended' dose is 20mg of omeprazole daily, a dose that inhibits gastric secretion in 5@70% of treated patients (118,(125)(126)(127) and increases gastrin levels in the same proportion (123). Unfortunately, no estimates of gastric secretion and gastrin release have been reported in the same individual patients.…”