Twice-daily sucralfate dosing to heal acute duodenal ulcer. Multicenter Study Group

Effect of sucralfate on gastric mucosal calcium channels activity

1. The effect of anti-ulcer agent, sucralfate, on the activity of the gastric mucosal calcium channel was investigated using calcium channels purified from rat gastric epithelial cell membranes. 2. The channels on reconstitution into phosphatidylcholine vesicles responded in a concentration-dependent manner to a calcium channel activator, BAY K8644, as well as to a calcium channel antagonist, PN200-110. The 45Ca2+ uptake was inhibited by sucralfate. Maximum inhibitory effect was attained at 100 micrograms/ml sucralfate, at which point a 52% decrease in the uptake occurred. 3. EGF-induced channel protein phosphorylation showed an increase in tyrosine phosphorylation of 55 and 170 kDa proteins, and the vesicles containing the phosphorylated channels displayed a 48% greater 45Ca2+ uptake. This phosphorylation process was inhibited by sucralfate. Furthermore, sucralfate also interfered with the binding of EGF to calcium channel protein. 4. The results indicate that sucralfate protects the cellular integrity from calcium imbalance by modulating the EGF-stimulated gastric mucosal calcium channel phosphorylation.

Pharmacodynamics as a tool to assess the bioequivalence of non-systemically available drugs: size of the sample required

Bioequivalence studies of drugs which are not systematically available must rely on the measure of the pharmacological response. Detection of a difference between two such preparations is often hampered by the need to include an elevated number of subjects. The number of subjects can be reduced whenever: (a) the characteristics of the subjects are well defined, (b) the selection of the baseline target effect is done rigorously, (c) the target effect can be quantified reliably, (d) the effect is measured when less variability is expected, e.g. at steady state, (e) the effect is measured repeatedly, and (f) when possible, the predicted maximal effect (Emax) and the concentration to elicit 50% of Emax are estimated. A simple equation has been derived to estimate the number of subjects needed in these bioequivalence studies.

Practical pharmacology and cost-effective management of peptic ulcer disease

The clinical approach to the therapy of peptic ulcer disease has changed over the years as our understanding of its pathogenesis has grown. No longer is excess acid production seen as the single cause of ulcer disease; rather, its pathogenesis is viewed as the disturbance of a complex balance of ulcerogenic and protective factors. Today, the clinician's aim is to restore the balance between protective and aggressive factors. Simultaneously, the development of new classes of medications has provided the clinician with the tools to decrease intragastric acidity, neutralize or suppress acid production, and enhance the protective and restorative properties of the mucosa.

Treatment of peptic ulcer disease with sucralfate: a review

Sucralfate has been used widely for the treatment of peptic ulcer. Healing rates for duodenal ulcer range from 60 to 90% at 4-6 weeks and up to 90% at 12 weeks for gastric ulcer. The small number of maintenance trials suggest that relapse of duodenal ulcer is reduced comparably to H2 receptor antagonists. There has been considerable interest in the possibility of lower relapse ratios after initial healing with sucralfate compared with H2 receptor antagonists, but more studies of the possible mechanisms as well as larger trials are still needed to confirm these observations.

Comparative study of sucralfate 2 grams twice daily versus sucralfate 1 gram four times daily in the treatment of benign gastric ulcers in outpatients

In a double-blind, randomized study, we compared the healing of gastric ulcer during a twice-daily regimen of 2 g sucralfate or sucralfate 1 g q.i.d. Patients receiving the former therapy received the tablets one-half hour before breakfast and at bedtime. Patients receiving sucralfate 1 g q.i.d. received their therapy 30 minutes before breakfast, lunch, and supper, and at bedtime. The study included 52 patients with endoscopically proven gastric ulcer; 41 patients completed the study. Healing was endoscopically assessed at 8 weeks and 12 weeks. After 8 and 12 weeks the healing rate for sucralfate 2 g b.i.d. was 67% and 92%, respectively; the healing rate of sucralfate 1 g q.i.d. was 59% and 71%, respectively. No statistically significant difference was found between the two regimens. The results suggest that 2 g sucralfate twice daily is as effective in the healing of gastric ulcer as 1 g sucralfate q.i.d.

Treatment of duodenal ulcer with sucralfate

Sucralfate attains a healing rate of about 79% for duodenal ulcer in 4 weeks, which is similar to the effects of cimetidine and ranitidine. Whereas cigarette smoking significantly affects duodenal ulcer healing by acid-reducing agents, the healing rates of smokers and non-smokers treated with sucralfate or colloidal bismuth are indistinguishable, suggesting an inherent advantage through the cytoprotective mechanisms of these agents. The 12-month relapse curves for duodenal ulcers initially healed with sucralfate and colloidal bismuth subcitrate closely overlap each other and are significantly lower than the curves for the histamine H2-receptor antagonists. These findings cannot be accounted for by clearance of Helicobacter pylori, on which sucralfate has little effect. Preliminary evidence suggests that the use of acid-reducing agents results in up-regulation of the parietal cells and may help to explain the differences in relapse rates. Sucralfate is superior to placebo and comparable to H2 antagonists in the prevention of duodenal ulcer recurrence.

Why do ulcers heal with sucralfate?

It is unknown why ulcers in general heal. Some clues are worth considering. What is known is (i) that ulcer healing occurs spontaneously, (ii) that ulcers heal more quickly in the duodenum than in the stomach, (iii) that mucosal blood flow at ulcer edge improves with healing, and (iv) that healing can be speeded up by (a) not smoking, (b) removing acid from the stomach, and (c) using non-antisecretory mucosal protective agents such as sucralfate and colloidal bismuth. The difference in healing rates between duodenal and gastric ulcers may be related to ulcer size, duodenal alkalinity due to the secretion of the Brunner's glands, and other uninvestigated factors such as epidermal growth factor and mucosal blood flow. The difference between smokers and non-smokers may be related to inhibition of prostaglandin synthesis and impairment of mucosal blood flow due to smoking and to higher acid secretion in smokers. The success with antisecretory agents indicates that acid inhibits the healing process. The success of sucralfate and bismuth indicates that cytoprotective mechanisms play a role in ulcer healing. The literature also shows that ulcer healing is less affected by smoking in patients treated with sucralfate than in those treated with antisecretory agents, suggesting that cytoprotective mechanisms play a more important part than acid inhibition in counteracting the adverse effects of smoking on healing. Furthermore, ulcer relapse occurs sooner in patients treated with antisecretory agents than in those treated with sucralfate or bismuth, suggesting that withdrawal of antisecretory agents speeds up relapse and/or that cytoprotective mechanisms are associated with longer-lasting remission. It is concluded that sucralfate healing involves cytoprotective mechanisms and that these cannot be ignored in the planning of any anti-ulcer therapy. Despite the understanding of the various site-protective and cytoprotective mechanisms, as discussed in the previous article, it is not clear why ulcers heal with sucralfate. In fact, there is no clear answer to the fundamental question as to why ulcers in general heal with the known therapeutic agents, including H2-receptor antagonists, antacids, proton pump inhibitors, anticholinergics, site-protective agents, and cytoprotective agents. This review examines this question, using sucralfate as a model.

Implications of sucralfate-induced ulcer healing and relapse

A review of the literature indicates that sucralfate attains a healing rate of 79 percent for duodenal ulcer and 75 percent for gastric ulcer in four and eight weeks, respectively, rates not different from those reported for cimetidine and ranitidine. Meta-analyses show that, whereas cigarette smoking significantly affects duodenal ulcer healing by acid-reducing agents, the healing rates of smokers and non-smokers treated with sucralfate are indistinguishable, suggesting an inherent advantage through the underlying mechanisms of the drug. Pooling reports in the literature indicates that the 12-month relapse curves of duodenal ulcers initially healed with sucralfate and colloidal bismuth subcitrate closely overlap each other and are significantly lower than the curves of the histamine (H2)-receptor antagonists under comparison. A review of the ulcer relapse rates following initial healing in the literature shows that patients receiving acid-reducing agents such as antacids, H2-receptor antagonists, and omeprazole have relapses at similar rates. Use of anticholinergics or non-antisecretory agents including carbenoxolone sodium is associated with a longer remission. Preliminary evidence is available to support the concept that the use of acid-reducing agents results in up-regulation, whereas the use of anticholinergics and non-antisecretory agents is associated with down-regulation of the parietal cells. These changes at the molecular level may help to explain the differences in relapse rates following initial healing with various anti-ulcer agents.