Sucralfate, Bismuth Compounds, Substituted Benzimidazoles, Trimipramine and Pirenzepine in the Short- and Long-term Treatment of Duodenal Ulcer

Maintenance therapy for duodenal ulcer: a randomized controlled comparison of seven forms of treatment

PURPOSE

We performed a randomized controlled trial to compare the efficacy of seven forms of maintenance treatment of duodenal ulcer, including a mealtime regimen of antacids.

PATIENTS AND METHODS

We randomized 785 patients with healed duodenal ulcer to receive: (1) no treatment; (2) mealtime antacids with an acid-neutralizing capacity of 80 mmol/day; (3) an antidepressant, trimipramine 25 mg; (4) an anticholinergic, pirenzepine 50 mg; (5) cimetidine 200 mg; (6) cimetidine 400 mg; (7) ranitidine 150 mg; or (8) sucralfate 1 g twice a day. Symptomatology and side effects were assessed every 2 months and endoscopy was performed every 4 months up to 1 year.

RESULTS

The patients were comparable in the majority of clinical characteristics before entry. The cumulative percentages of patients with relapse of ulcers at 12 months by life-table analysis were 61% with no treatment, 38% with mealtime antacids, 60% with trimipramine, 52% with pirenzepine, 46% with cimetidine 200 mg, 44% with cimetidine 400 mg, 30% with ranitidine 150 mg, and 40% with sucralfate. Cimetidine 400 mg, antacids, ranitidine 150 mg, and sucralfate were significantly better than no treatment and the other forms of treatment. Ranitidine was significantly better than antacids, cimetidine, and sucralfate in preventing endoscopically documented duodenal ulcer relapse by multiple comparison at 12 months, but not by life-table analysis nor when symptomatic relapses were compared. No significant difference was detected among antacids, cimetidine, and sucralfate. No major side effects occurred with the seven forms of treatment, but those receiving antacids had the highest incidence of minor adverse events (26%).

CONCLUSION

This study suggests that mealtime antacids are as effective as H2-receptor antagonists and sucralfate in the maintenance treatment of duodenal ulcer disease, but have to be taken three times a day and had the highest incidence of reported minor adverse events. The relapse rate was lower with ranitidine than with cimetidine, sucralfate, and antacids, but the difference was small and may not be clinically important.

Combination therapy of sucralfate and ranitidine, compared with sucralfate monotherapy, in patients with peptic reflux esophagitis

A double-blind, multicenter, randomized study was performed in 75 patients with endoscopically documented reflux esophagitis. Patients were randomly given 1 g sucralfate four times a day or the combination of sucralfate three times a day and 300 mg ranitidine after dinnertime. Endoscopy was performed at the beginning of the study, after 8 weeks, and, if, the reflux esophagitis was not healed, after 16 weeks. Four patients had to be excluded from evaluation; 71 patients could therefore be evaluated. Both groups showed symptomatic improvement to similar extents. Endoscopy showed symptomatic improvement in 67% of the patients treated with sucralfate and in 74% of the combination therapy group. Complete healing or Savary-Miller stage 1 was seen in 26.5% and in 31.4%, respectively. We conclude that sucralfate monotherapy in patients with milder forms of reflux esophagitis is comparable with a combination of sucralfate during the day and ranitidine after dinnertime. This study does not support the commonly used combination of sucralfate and H2-receptor antagonists in reflux esophagitis.

Histological maturity of healed duodenal ulcers and ulcer recurrence after treatment with colloidal bismuth subcitrate or cimetidine

The relationship between histological maturity of healed duodenal ulcers and ulcer recurrence after 6 weeks of treatment with colloidal bismuth subcitrate or cimetidine was investigated. There was no significant difference in healing rates between colloidal bismuth subcitrate- and cimetidine-treated patients (85.7% and 71.8%, respectively; P greater than 0.05). Histologically, the regenerating mucosa of healed ulcers was divided into three categories--good, fair, and poor--according to pattern. Sixty percent of healed colloidal bismuth subcitrate-treated and 30.9% of healed cimetidine-treated ulcers had a good pattern; the difference was statistically significant (P = 0.027). The difference in recurrence rates between healed colloidal bismuth subcitrate-treated and healed cimetidine-treated patients was statistically significant at 3 months (3.45% and 20%, respectively; P = 0.044). All recurrent ulcers in both groups had fair or poor patterns of regenerating mucosa. It was concluded that the greater histological maturity of the regenerating mucosa may contribute to the lower recurrence rate in colloidal bismuth subcitrate-treated patients than in cimetidine-treated patients.

Role of acid milieu in the gastroprotective and ulcer-healing activity of sucralfate

Sucralfate prevents the formation of acute gastric lesions induced by various ulcerogens and enhances the healing of chronic gastroduodenal ulcerations, but the mechanism of these effects has not been fully explained. This study was designed to determine the importance of intragastric pH in the sucralfate-induced gastroprotection against 100% ethanol, acidified aspirin, taurocholate, or stress, and in the healing of chronic gastroduodenal ulcerations induced by acetic acid. Sucralfate acidified to pH 2.0 showed significantly stronger protective activity against all four irritants, its protective potency against 100% ethanol being about eight times greater and the duration of the protection about four times longer than those obtained with sucralfate at its pH of 5.0. Pretreatment with indomethacin to suppress mucosal generation of prostaglandin or the removal of salivary glands to eliminate the endogenous source of epidermal growth factor failed to affect sucralfate-induced gastroprotection. In contrast, the rate of healing of chronic gastric ulcerations was significantly delayed by indomethacin or sialoadenectomy; but sucralfate enhanced the healing, and a marked inhibition of gastric acid secretion by ranitidine did not eliminate this enhancement. We conclude that the protective activity of sucralfate depends on the presence of acid milieu in the stomach, but that the ulcer-healing effects of this drug occur even after a marked inhibition of gastric acid secretion.

Efficacy of misoprostol and ranitidine in the prevention of duodenal ulcer relapse and its correlation with endogenous gastric prostanoid synthesis

We determined endogenous gastric prostaglandin synthesis and its correlation with the prevention of duodenal ulcer relapse by misoprostol and ranitidine. Sixty-one patients with recent endoscopically healed duodenal ulcer were randomly allocated in a double-blind fashion for one year of treatment with misoprostol 400 micrograms nocte, ranitidine 150 mg nocte or placebo. Patients were followed every two months. Endoscopy was repeated at six and 12 months or beforehand, if relapse was suspected. Antral and fundic biopsies, 3-4 from each region, were obtained at each endoscopy for determination of prostaglandin synthesis. During the one year of treatment, 11 out of the 12 placebo treated patients flared up, as opposed to 10 out of 25 and four out of 24 misoprostol and ranitidine treated patients, respectively. The difference between all treatment groups was significant (P less than 0.0001). In all subjects who flared up, pretrial endogenous antral and fundic prostaglandin E2 synthesis were not different from their respective synthesis in those who did not relapse.

Bismuth subsalicylate reduces peptic injury of the oesophagus in rabbits

Bismuth subsalicylate was tested in an in vivo perfused rabbit model of oesophagitis for its ability to prevent the mucosal injury caused by pepsin. Treatment efficacy was assessed under both a treatment-before-injury protocol and a treatment-after-injury protocol. Oesophageal mucosal barrier function was evaluated by measuring flux rates of H+, K+, and glucose. The degree of oesophagitis was determined by gross and microscopic examination of the mucosa by several independent observers. Results showed that under both treatment protocols, bismuth subsalicylate significantly reduced the pepsin induced disruption of the mucosal barrier, as well as the morphologic changes. Bismuth subsalicylate when given after exposure to pepsin was also found to protect against the morphologic injury in a dose dependent manner. Experiments in vitro suggested that bismuth subsalicylate inhibits the proteolytic action of pepsin by interacting with pepsin, rather than with the pepsin substrate. We conclude that bismuth subsalicylate can protect the oesophageal mucosa against peptic injury, probably through inactivation of pepsin.

Combination therapy of sucralfate and cimetidine, compared with sucralfate monotherapy, in patients with peptic reflux esophagitis

A double-blind multicenter, randomized study was performed in 70 patients with endoscopically documented reflex esophagitis. Patients were randomly given 1 g sucralfate four times a day or the combination of sucralfate 1 g three times a day and 400 mg cimetidine at night. After healing of the esophagitis, patients were randomly given either sucralfate maintenance 2 g daily or placebo for a period of six months. Endoscopy was performed at the beginning of the study, after eight weeks, and, in cases with no healing, after 16 weeks of therapy. Sixty-three of the 70 patients who initially entered the study could be evaluated after eight weeks. Both groups showed good symptomatic improvement, and no side effects necessitated withdrawal of subjects. Endoscopy showed complete healing in 19.4 percent of the sucralfate group and in 21.9 percent of the combination sucralfate and cimetidine group. Endoscopic improvement was found in 50 percent of the sucralfate group and in 50 percent of the combination group. After 16 weeks, 56 patients could be evaluated. In the sucralfate group, improvement was seen in 78.6 percent, and healing in 31 percent. For the combination group these values were 59.3 percent and 37 percent (not significant). Twenty-six patients entered the maintenance phase of the study; 15 received sucralfate and 11 received placebo. Evaluation of 20 patients after six months showed endoscopic and/or symptomatic relapse of esophagitis in three of 12 patients receiving sucralfate and in two of the eight patients receiving placebo. It is concluded that sucralfate monotherapy in patients with reflux-esophagitis is effective and comparable with a combination of sucralfate during the day and cimetidine at night. No difference was found between sucralfate and placebo in terms of the relapse rate of esophagitis during long-term treatment.

Bismuth: effects on gastritis and peptic ulcer

The healing properties of colloidal bismuth subcitrate (CBS) on peptic ulcer are well established and several studies have shown that healing with CBS is associated with a lower relapse rate than that produced by H2-receptor antagonists. The recent observation that CBS is effective against Campylobacter pylori has shed light on this because recent studies have shown that eradication of C. pylori by CBS leads to resolution of the associated gastritis and this may explain the low relapse rates. CBS is also effective in C. pylori positive patients with non ulcer dyspepsia (NUD) in whom clearance of these organisms from the stomach is associated with significant improvement of the associated gastritis and symptoms.

De-Nol stimulates gastric and duodenal alkaline secretion through prostaglandin dependent mechanism

This study was designed to determine the effects of colloidal bismuth subcitrate De-Nol on gastric HCO3- secretion in 24 healthy subjects and on gastric and duodenal HCO3- secretion in dogs with gastric and duodenal fistulae. Alkaline secretion was measured after pretreatment with ranitidine to abolish the H+ secretion using a constant perfusion aspiration system and back titration of the perfusates to the original pH 6.0. Luminal release of PGE2 was also measured in the gastric and duodenal perfusates. Addition of De-Nol in gradually increasing concentrations resulted in step wise increments in gastric HCO3- secretion in man and in dogs reaching, respectively, about 80% and 55% of the maximal HCO3- response to 16, 16dimethyl-PGE2 (dmPGE2). The duodenal HCO3- response to De-Nol in dogs reached 72% of the dmPGE2 maximum. These effects were accompanied by a significant increase in luminal release of PGE2. Pretreatment with atropine reduced basal and in part De-Nol induced alkaline secretion, whereas pirenzepine did not affect this secretion in man and dogs. Aspirin (in man) and indomethacin (in dogs) reduced the release of PGE2 by about 80% and suppressed almost completely the gastric and duodenal HCO3- response to De-Nol in these species. This study provides evidence that De-Nol stimulates gastroduodenal alkaline secretion through a prostaglandin dependent mechanism.

The medical therapy of reflux oesophagitis

Besides changes in behaviour and lifestyle we nowadays have the choice of specific drugs in the treatment of reflux oesophagitis. A distinction can be made in motility modulating drugs, which stimulate oesophageal peristalsis and LOS pressure, mucosa-protecting drugs, which form a protective layer on the oesophageal mucosa, acid neutralizing (antacids) and acid suppressing drugs (H2-receptor antagonists, omeprazole). So far the results of medical therapy of reflux oesophagitis are still suboptimal. Giving the H2-receptor antagonists with the evening meal would possibly be more appropriate. A valid alternative is the mucosa-protecting agent sucralfate. Monotherapy will probably be insufficient for full healing, which explains why trials of combination therapy (H2-receptor antagonists plus sucralfate or plus cisapride) are being conducted. If omeprazole becomes available, it will revolutionize the therapy of severe reflux oesophagitis. Many questions (dose, duration, maintenance, safety monitoring etc.) remain to be determined.

Effects of sucralfate on gastroduodenal bicarbonate secretion and prostaglandin E2 metabolism

The mechanism of action of sucralfate has been investigated. Using homogenized rabbit mucosa, the drug increased arachidonic acid conversion to prostaglandin E2 without affecting catabolism. Luminal administration of sucralfate (0.5 g/liter) caused marked stimulation of bicarbonate secretion by isolated amphibian gastric mucosa but not duodenal mucosa. In a higher dose (1 g/liter), duodenal bicarbonate secretion was also stimulated. These effects are likely to be due to endogenous prostaglandin formation since they are inhibited by indomethacin. The results suggest that the cytoprotective action of sucralfate is due to stimulation of endogenous prostaglandin formation and may involve various mucosal defensive factors.

Clinical efficacy of sucralfate in reflux esophagitis. Comparison with cimetidine

Sucralfate has been evaluated in reflux esophagitis, based on its protective adherence to denuded surfaces, its bile salt-binding properties, and its cytoprotective properties. Histamine (H2)-receptor blockers are currently considered the standard therapy. The goal of this study was to compare the potential efficacy of sucralfate with that of cimetidine. A single-blind, randomized, multicenter study was performed in 42 patients with endoscopically documented reflux esophagitis. Patients were randomly given 1 g of sucralfate suspension four times daily or 400 mg of cimetidine four times daily for eight weeks. Forty patients were evaluated after eight weeks. Symptomatic improvement was good and comparable in both groups. In two patients given sucralfate and one given cimetidine, side effects were noted but did not necessitate withdrawal from the study. Endoscopy showed improvement in 53 percent of patients and healing of esophagitis in 31 percent after sucralfate treatment. With cimetidine, improvement was seen in 67 percent and healing occurred in 14 percent. In one patient receiving cimetidine, distal esophageal stenosis developed, requiring dilatation therapy. It is concluded that treatment with sucralfate improves the symptomatology and severity of reflux esophagitis. The results obtained with sucralfate appear comparable to those with cimetidine. Sucralfate may therefore be considered as a valid alternative to H2-receptor antagonist therapy in treating reflux esophagitis.

Short-term treatment of prepyloric ulcer. Comparison of sucralfate and cimetidine

A double-blind, randomized, multicenter study was performed to compare the effect of sucralfate (1 g qid) and cimetidine (400 mg bid) in the treatment of prepyloric ulcer. Altogether 142 patients (68 in the sucralfate and 74 in the cimetidine group) with endoscopically confirmed ulcer within 2 cm of the pylorus completed the study. Endoscopic follow up was performed after four weeks and, if the ulcer was not healed, after eight weeks of treatment. After four weeks, 65% of the ulcers in the sucralfate group were healed, compared to 70% in the cimetidine group. There was no significant difference between sucralfate and cimetidine at either time point. The 95% confidence interval for the difference in ulcer healing with sucralfate or cimetidine ranged from +4 to -19% at eight weeks. Said another way, with an observed difference of 7% (83% vs 90%), the 95% confidence limit ranged from 4% in favor of sucralfate to 19% in favor of cimetidine. Symptomatic relief, antacid intake, and side effects did not differ significantly between the two groups. The healing rate of prepyloric ulcer in this study is similar to that reported for duodenal ulcer after four and eight weeks when treated with sucralfate or cimetidine. Sucralfate is safe and as effective as cimetidine in the short-term treatment of prepyloric ulcer.

Randomized, double-blind, placebo-controlled crossover trial of cimetidine and pirenzepine in nonulcer dyspepsia

Nonulcer dyspepsia remains a difficult disorder to treat because it is a heterogeneous syndrome. Once patients with the irritable bowel syndrome, esophagitis, and other organic diseases are excluded, there remain patients with dyspepsia of unknown cause (termed "essential dyspepsia") and patients with dyspepsia plus symptoms of gastroesophageal reflux without esophagitis. The aim of this study was to determine whether cimetidine or pirenzepine is efficacious in relieving the symptoms of these latter subgroups. Sixty-two consecutive patients were studied who had chronic upper abdominal pain or nausea where endoscopy had shown no evidence of peptic ulceration, esophagitis, or malignancy; 47 had essential dyspepsia, and 15 had dyspepsia plus gastroesophageal reflux. They were initially randomized to either cimetidine or placebo, or pirenzepine or placebo. Patients continued each medication for 1 mo, and, after a washout period, crossed over when again symptomatic; 51 patients completed cimetidine and placebo, and 50 completed pirenzepine and placebo. The results showed that cimetidine was superior to placebo in decreasing the number of upper abdominal pain episodes weekly and the severity of pain, but the absolute improvement was small. Pirenzepine was not superior to placebo in decreasing symptoms.

The pathophysiology of peptic ulcer disease

Heterogeneity is the most important consideration in the pathophysiology of peptic ulcer disease. Acute ulcers and erosions present clinically with gastrointestinal bleeding or perforation. If they heal there is no predictable recurrence. Factors concerned with mucosal defense are relatively more important than aggressive factors such as acid and pepsin. Local ischemia is the earliest recognizable gross lesion. The gastric mucosa is at least as vulnerable as the duodenal mucosa and probably more so. Most drug-induced ulcers occur in the stomach. Chronic or recurrent true peptic ulcers (penetrating the muscularis mucosae) usually present with abdominal pain. Many duodenal ulcer patients report that the pain occurs when the stomach is empty or is relieved by food, and follows a pattern of relatively long periods of freedom from symptoms between recurrences. Approximately 50% of patients experience a recurrence within a year if anti-ulcer medication is stopped. In most western countries recurrent duodenal ulcer is more common than gastric ulcer. Peptic ulcer disease is also more common in men. Recent evidence indicates genetic and familial factors in duodenal ulcer and increased acid-pepsin secretion in response to a variety of stimuli. However, it is also becoming clear that of all the abnormal functions noted, few are present in all subjects and many are clustered in subgroups. In chronic gastric ulcer of the corpus, defective defense mechanisms, such as duodenogastric reflux and atrophic gastritis, seem to be more important than aggressive factors. Nevertheless, antisecretory medications accelerate the healing of such ulcers. It remains to be seen whether prostaglandins, mucus secretion, or gastric mucosal blood flow are impaired in chronic ulcer disease.

Therapeutic approach to ulcer healing

The healing rate of duodenal ulcers may be accelerated by secretory inhibitors such as histamine H2-receptor antagonists and pirenzepine, by antacids, by protective drugs such as sucralfate and colloidal bismuth, and by antidepressant drugs such as trimipramine. The effect of these drugs on the rate of healing is comparable; they differ with respect to practicability of treatment, incidence and types of side effects, and suitability for long-term administration. Currently, the most versatile and most thoroughly investigated drugs are the histamine H2-receptor antagonists.