Prevention and treatment of gastrointestinal mucosal injury with cytoprotective agents

Treatment of peptic ulcer disease in the arthritic patient

Dyspepsia associated with arthritis and non-steroidal anti-inflammatory drugs (NSAIDs) is a common clinical problem. Up to 80% of deaths attributable to peptic ulceration may be associated with NSAID usage. The problem is foremost in the elderly population, in which there has been an increase both in the incidence of peptic ulcers and in the use of NSAIDs. Although the development of duodenal ulceration is not clearly associated with NSAIDs, it is accepted that these drugs increase the risk of gastric ulceration and the occurrence of peptic ulcer complications. Asymptomatic peptic ulceration is common, and patients taking NSAIDs are often asymptomatic prior to presentation with life-threatening complications. The key principle in management of this problem is prevention through careful selection of patients for NSAID use, adequate treatment of peptic ulceration and maintenance of remission. A variety of effective drugs are available for the treatment of peptic ulcers, including H2-receptor antagonists, pirenzepine, sucralfate and colloidal bismuth subcitrate. However, it is recognised that peptic ulceration is a chronic disease with a relapsing-remitting course, often with asymptomatic ulcer episodes. The knowledge that current ulcer-healing strategies do not significantly alter this natural history has lead to increasing efforts to prevent relapse with effective 'maintenance' therapy.

Efficacy of sucralfate in refractory reflux esophagitis. Results of a pilot study

Patients with severe reflux esophagitis unresponsive to standard medical therapy constitute a vexing clinical problem. We evaluated 8 patients with long-standing gastroesophageal reflux disease complicated by peptic stricture (n = 6), Barrett's esophagus (n = 5), bleeding esophageal ulcer (n = 2), and/or failure or prior antireflux surgery (n = 4), and 4 patients with rapidly advancing esophagitis following surgical resection of the cardia. After an 8-week course of full-dose H2-receptor antagonists, domperidone and antacids, marginal clinical improvement and unchanged or worsened endoscopic appearance of esophagitis was observed in all patients. Thereafter, in an attempt to enhance esophageal mucosal resistance, sucralfate alone (4.0 g/d) was given for 8 weeks. Both symptoms and endoscopic appearance improved in all patients after sucralfate, and the need for dilatation of strictures was lessened. On follow-up, complete healing of esophagitis was demonstrated by endoscopy in 6 patients after 4 to 6 months of uninterrupted sucralfate therapy. The results of this pilot study indicate that (cyto)protection with sucralfate has an important therapeutic potential in reflux esophagitis. They also suggest that impaired esophageal epithelial resistance is an important pathophysiological factor in persistence of esophageal inflammation in esophagitis refractory to conventional treatment.

Gastric prostaglandin E2 release induced by aluminium hydroxide and aluminium hydroxide-containing antacids in rats. Effect of low doses and citric acid

Suspensions of aluminium hydroxide or a commercial antacid containing aluminium hydroxide (Trigastril) was instilled intragastrically in rats in doses comparable to high and low human therapeutic doses (aluminium hydroxide, 125 mg and 12.5 mg/kg, respectively). Corresponding experiments were carried out with 0.6% citric acid added to the antacid suspensions. Prostaglandin E2 (PGE2) in the gastric content was analysed by radioimmunoassay 6 h after drug administration. Both high and low doses of aluminium hydroxide and Trigastril increased the concentration of PGE2 significantly. Citric acid did not significantly affect the antacid-induced PGE2 release except in combination with a low dose of aluminium hydroxide, with which a significant increase was seen. Release of PGE2 by low doses of antacids implies the possibility that enhanced cytoprotection may be involved in the mechanism by which antacids promote the healing of peptic ulcers.

Future treatment of peptic ulcers

Drugs which abolish acid secretion and promise improved ulcer healing rates have produced dysplasia and tumours in experimental animals given large doses for long periods. Solutions to this problem will be based on better understanding of the mechanisms involved. Healing rates might be improved by combining inhibitors of acid secretion with ulcer protectors which, unlike currently available agents, are designed to work well in the presence of diminished acid secretion. Drugs which increase mucosal defence might best be used to prevent ulceration, so the need is to develop agents which are safe for long term use.