Therapeutic achlorhydria and risk of gastric cancer

Proton Pump Inhibitors in the Elderly, Balancing Risk and Benefit: an Age-Old Problem

PURPOSE OF REVIEW

Proton pump inhibitors (PPIs) are one of the most prescribed drugs in the developed world and elderly patients are particularly likely to be prescribed acid suppression. There have been reports of many diseases being associated with PPI therapy and the elderly would be particular at risk of any harms these drugs may cause. This review therefore reviews the evidence of the risks and benefits of these drugs.

RECENT FINDINGS

PPIs are very effective at treating acid-related disorders. Recent randomized trials have suggested that the associations between PPI and various diseases are likely to be related to bias and residual confounding and these drugs appear to be safe apart from a possible increase risk of enteric infections. PPIs should be used at the lowest dose and for the shortest duration possible. They are still relatively safe drugs but should only be prescribed for proven indications.

Maintenance therapy for peptic ulcer disease

Peptic ulcers tend to recur; recurrence may be associated with an increased risk of potentially lethal complications, such as haemorrhage or perforation. Therapy aims to keep ulcers in remission. Currently, the optimal maintenance therapy is long-term, continuous administration of antisecretory drugs. More than 80% of patients remain in remission during maintenance therapy. Maintenance therapy may be required for the life of the patient, but it is acceptable to patients and is safe.

Gastric gland degeneration induced in monkeys by the CCK-B/gastrin receptor antagonist CI-988

Gastric effects of subchronic treatment with the cholecystokinin-B (CCK-B)/gastrin receptor antagonist CI-988 were investigated in cynomolgus monkeys. In preliminary range-finding studies, CI-988 was given orally to 1 monkey per sex for 14 days at doses of 50, 100, 200, and 500 mg/kg/day. Subchronic studies of CI-988 were subsequently conducted using 5 monkeys per sex at doses of 0, 5, 25, and 75 mg/kg for 4 or 13 wk. High-dose monkeys were dosed initially at 100 mg/kg, but the dose was not well tolerated and was decreased to 75 mg/kg after 8 days of treatment. One male monkey at 75 mg/kg was euthanatized in extremis on day 23. In the range-finding study, minimal to moderate, multifocal to diffuse degeneration of gastric glands, primarily in the fundic region, was observed at 100 mg/kg and above, with frank gastric mucosal atrophy occurring at 200 and 500 mg/kg. Minimal to mild gastric gland degeneration was also observed in the subchronic study after 4 wk at 25 and 75 mg/kg, but histopathologic gastric changes were remarkably absent after 13 wk. Mucosal height in the stomach fundus was decreased 19.8% in 75-mg/kg males at week 4, and although gastric mucosa appeared histologically normal after 13 wk, mucosal height remained 28.6% less than that of controls. In females at 75 mg/kg, fundic mucosal height was decreased 7% and 5% at weeks 4 and 13, respectively, but decreases were not statistically significant. Mean serum gastrin concentrations were increased 10-fold in males only after 4 wk at 75 mg/kg, but were comparable to controls during week 13. CI-988-induced gastric gland degeneration is consistent with antagonism of gastrin's trophic activity toward gastric mucosa. Notwithstanding decrements in gastric mucosal height, disappearance of mild histopathologic findings despite continued treatment with the ligand suggests some degree of adaptation to subchronic CCK-B/gastrin inhibition, although the mechanism of accommodation has yet to be delineated.

Review article: maintenance treatment with H2-receptor antagonists for peptic ulcer disease

In recent years a number of different strategies for managing patients with peptic ulcer disease have become available. The present review discusses the relative merits of each form of treatment. Intermittent treatment (whether given in response to symptoms or as a prophylactic regimen prescribed seasonally or at weekends) fails to prevent ulcer recurrence and leaves patients at risk of haemorrhage and perforation. Anti-Helicobacter pylori therapy, although useful in certain circumstances, cannot be recommended for all patients with ulcer disease because of side effects and, in any case, requires further assessment of efficacy. Gastric surgery reduces ulcer recurrence and complications, but operations which have a low incidence of side effects are associated with higher rates of ulcer recurrence, particularly when patients are followed up for more than 10 years. Long-term continuous maintenance treatment with H2-receptor antagonists for 5 or more years effectively prevents ulcer recurrence in the majority of patients and significantly reduces the risk of ulcer complications. In addition, maintenance treatment has proved to be safe and is well tolerated by patients. Maintenance treatment with H2-receptor antagonists is the preferred option for the management of patients with peptic ulcer disease.

Is hypergastrinaemia dangerous for man?

Several gastric mucosal diseases and the response to powerful gastric secretory inhibitors are accompanied by hypergastrinaemia. When the gastric mucosa is functioning normally, hypergastrinaemia may be dangerous as a consequence of gastric hypersecretion. When the gastric mucosa is functionally abnormal, hypergastrinaemia produces no apparent adverse effects on health. However, the diseases giving rise to hypergastrinaemia are very dangerous because they are often the precursors of gastric cancer. In view of the probable mechanisms of gastric carcinogenesis, it is argued that therapeutic achlorhydria is also potentially dangerous irrespective of the absence or presence of 'hypergastrinaemia'.