Efficacy of sucralfate in corpus, prepyloric, and duodenal ulcer-associated gastric ulcers. A double-blind, placebo-controlled study

Stimulatory effects of sucralfate on secretion and synthesis of mucus by rabbit gastric mucosal cells. Involvement of phospholipase C

We examined the effects of sucralfate on the secretion and synthesis of mucus by cultured rabbit gastric mucosal cells, and the underlying intracellular mechanism. Treatment of mucosal cells with sucralfate (>0.5 mg/ml) for 4 and 8 hr caused a significant increase in the inositol triphosphate (IP3) content in the cells. Neomycin (a phospholipase C inhibitor) at 1 mM markedly inhibited the sucralfate-induced increases in both the IP3 content and mucus secretion and synthesis. Neither 10 nM staurosporine, 1 mM H-7 (protein kinase C inhibitors), nor 5 microM indomethacin (a cyclooxygenase inhibitor) affected the stimulatory effects of sucralfate on mucus secretion and synthesis, but 10 microM TMB-8 (an antagonist of intracellular Ca2+ mobilization)abolished its effects. Taken together, these results demonstrate that sucralfate acts directly an gastric mucosal cells, inducing increases in mucus secretion and synthesis, and that sucralfate causes an increase in the IP3 content, probably through activation of phospholipase C, and the subsequent IP3-elicited Ca2+ mobilization may be involved in the stimulatory effects of sucralfate.

Society stress and peptic ulcer perforation

To examine the relationship between society stress and peptic ulcer perforation, time-trend analysis was performed on the annual incidence of perforated peptic ulcer per 100,000 population in Hong Kong during the years 1962-85, when Hong Kong, as a developing city, went through significant socio-economic and political changes, and the trend was correlated with specially designed and validated society stress scores estimated annually during the same period. The society stress scores were derived independently by two expert panels blinded to the purpose of the study, one selecting and categorizing negative news events for Hong Kong during this period, and the other weighing the categories and scoring the impact of the news on Hong Kong. The incidence of perforation increased significantly during the years and manifested three distinct peaks, which coincided with the worst economic recession in Hong Kong, the influx of mainlander Chinese and Vietnamese boat people, and the Sino-British negotiation on the sovereignty of Hong Kong after 1997. Both linear and autoregression analysis, the latter taking into consideration point fluctuations in rates, showed that perforation rates correlated significantly with the society stress scores (r = 0.57, P < 0.002). The peak effects and the significant correlations indicate that an association exists between society stress and peptic ulcer perforation, and suggest that chronic society stress plays an important role in the aetiology of this condition, although the relatively low r value also suggests the presence of other aetiological factors.

Primary culture of rat gastric epithelial cells as an in vitro model to evaluate antiulcer agents

Primary rat gastric cell cultures were investigated as an in vitro model for evaluating antiulcer agents. Following exposure to concentrations of up to 5 mg/mL of an antiulcer agent sucralfate, an aluminum hydroxide complex of sucrose octasulfate, cultured cells were treated with either pH 3.5 medium or 3.5 mM indomethacin. Cytoprotection was evaluated by colony forming efficiency, neutral red uptake, and 3-(4,5-dimethyl-2-thiazoyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) hydrolysis. By each measure, and depending on damaging agent, 2 and 5 mg/mL sucralfate provided partial (50% of untreated control) to near-complete (90% of untreated control) cytoprotection, respectively. Aluminum hydroxide also provided partial (55% of untreated control) to near-complete (more than 90% of untreated control) cytoprotection at 2 and 5 mg/mL, respectively, for the pH 3.5 medium-induced damage. Over a concentration range of 0.05 to 5 mg/mL, the potassium salt of sucrose octasulfate, KSOS, stimulated cell growth up to 40-60% over untreated controls but had little or no cytoprotective action in the presence of either 3.5 mM indomethacin or pH 3.5 medium. Overall results suggested that sucralfate may have at least two roles in influencing gastric epithelial cell function, cytoprotection and stimulation of cell growth in vitro. These observations serve as a basis for further study of in vitro models in evaluating the cytoprotective activity of antiulcer agents and their respective mechanisms of action.

Peptic ulcer disease. How to treat it now

Options for treatment of peptic ulcer disease are becoming more diverse. Most new agents are effective yet offer no real advantage over more traditional therapy. However, omeprazole (Prilosec) may be of benefit owing to its potent inhibition of acid secretion, but it is not yet approved for this purpose. Whether treatment of Helicobacter pylori infection will prove beneficial is not yet known, but the answer should be forthcoming. Finally, as with any disease process, alleviation of risk factors is always important. Appropriate counseling regarding use of nonsteroidal anti-inflammatory drugs and cigarette smoking is a necessity.

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.

Effect of sucralfate on gastric mucosal blood flow in rats

Sucralfate possesses site protective and cytoprotective actions and heals ulcers effectively, but its effect on gastric mucosal blood flow is unknown. Using an ex vivo gastric chamber preparation, we studied the effect of sucralfate on gastric mucosal blood flow in rats by laser doppler flowmetry. Under both fasting and fed states, measurements of gastric mucosal blood flow and damage were made in rats after topical application of absolute ethanol alone or after pretreatment with sucralfate. Gastric mucosal damage was assessed by measuring the total area of haemorrhagic mucosal lesions. Ethanol induced gastric mucosal lesions were significantly less with sucralfate pretreatment than without (p less than 0.008). Mucosal blood flow significantly fell after ethanol application (p less than 0.001). The fall was significantly less in fed than in fasted rats (p less than 0.05), and after pretreatment with sucralfate 100 mg or 200 mg than without in both fasted (p less than 0.0008 and 0.00001, respectively) and fed (p less than 0.002 and 0.001, respectively) rats. Graded doses of sucralfate (25-400 mg) resulted in an increase in gastric mucosal blood flow in a dose dependent manner (r = 0.731, p less than 0.001). In conclusion that sucralfate increases gastric mucosal blood flow in rats and lessens the fall in blood flow in rats treated with ethanol, and this action may contribute to its protection against the vascular damage of mucosa by ethanol.

Lack of gastric mucosal protection by sucralfate during long-term aspirin ingestion in humans

The ability of sucralfate to prevent gastric mucosal erosions caused by long-term aspirin ingestion was studied in 19 normal human subjects. A placebo-controlled, double-blind, crossover design was used to study the capacity of 4 g sucralfate daily to lessen the noxious effect on gastric mucosa of 3.6 g aspirin daily for 14 days. Gastric mucosal injury was assessed by endoscopic scoring of erosions. There was no significant difference in mean erosion scores or the degree of partial mucosal protection between the two groups. It was concluded that sucralfate lacks a mucosal protection capacity at the dosage studied in human subjects ingesting large doses of aspirin over a two-week period.

Sucralfate protection of human gastric mucosa against acute ethanol injury

To assess the gastric mucosal protective action of sucralfate against alcohol, a double-blind, controlled, randomized study was carried out in 12 healthy adult men. All subjects received four treatments in a random sequence: sucralfate + ethanol, sucralfate + ethanol placebo, sucralfate placebo + ethanol, and sucralfate placebo + ethanol placebo. Fundal, antral, and duodenal mucosae were submitted to endoscopic examinations, and the antral mucosa underwent histologic examination before and after injury. Biopsy specimens were taken from the antral mucosa to determine by radioimmunoassay its capacity to synthesize prostaglandin E2, thromboxane B2, and 6-keto prostaglandin F1 alpha. In both the fundus and the antrum, the mean endoscopic injury score after sucralfate plus ethanol administration was significantly lower than that after ethanol alone. All treatments tended to increase prostanoid values but 6-keto prostaglandin F1 alpha increased significantly when sucralfate was given. Sucralfate did not affect serum ethanol levels, nor did ethanol affect prostanoid synthesis. It is concluded that sucralfate provides significant protection to the human gastric mucosa against ethanol injury, and that this may be partly due to increased prostanoid synthesis.

Sucralfate for prevention of naproxen-induced mucosal lesions in the proximal and distal gastrointestinal tract

To study the protective effect of Sucralfate on Naproxen-induced mucosal lesions, 16 healthy, male volunteers were given Naproxen 500 mg b.i.d. together with Sucralfate 2 g b.i.d. or placebo in a double-blind, crossover study. Drug periods were 1 week, with a 3-week wash out in between. Mucosal lesions in stomach and duodenum were assessed by upper endoscopy before and after each drug period, using a visual analogue with separate scoring of mid- and distal duodenal lesions. 51Cr-EDTA absorption tests were performed to demonstrate possible changes in distal gut permeability. In addition, subjective symptoms were registered. Both drug periods induced significant lesions in the stomach and duodenum. Statistically speaking, fewer changes were found in the stomach and duodenal bulb after Sucralfate co-administration, whereas no significant reduction of lesions was seen in the distal duodenum. The 51Cr-EDTA absorption was increased in both periods, indicating deleterious effects to distal parts of the gut, but our results did not demonstrate Sucralfate-mediated protection from these changes. Symptoms were modest, and equal in the two periods. We conclude that Sucralfate may offer protection in the gastric and proximal duodenal mucosa, but no such protective effect was seen distally to the duodenal bulb.

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.

Role of mucus and prostaglandins in the gastric mucosal protective actions of sucralfate against ethanol-induced injury in the rat

This study investigated the relationship between the protective effect of sucralfate against ethanol-induced gastric mucosal injury in the rat and the effects of sucralfate on prostaglandin and mucus synthesis and secretion. Sucralfate at 200, 400, and 800 mg/kg significantly reduced gastric ulceration. Intragastric administration of sucralfate increased luminal mucus and prostaglandin E2 levels but did not affect prostaglandin or mucus synthesis in gastric mucosal biopsy specimens from sucralfate-treated animals. Pretreatment with indomethacin partially reduced the protective effect of sucralfate. However, sucralfate 200 mg/kg, a dose that completely prevented ulceration, did not increase the levels of luminal prostaglandin E2. In vitro incubation with sucralfate did not stimulate mucosal prostaglandin synthesis. Longer-term administration of sucralfate for 48 or 96 hours did not stimulate mucus or prostaglandin synthesis but did increase luminal prostaglandin E2 and mucus. Although sucralfate increased the gastric juice content of prostaglandin E2 and mucus, the two did not appear to be mechanistically related, and only mucus release was consistently associated with mucosal protection.

Comparison of two sucralfate dosages presented in tablet form in duodenal ulcer healing

Two hundred twenty-two patients with endoscopically proven duodenal ulcers participated in a controlled trial to assess and compare the effects of two dosage regimens of sucralfate tablets on ulcer healing, i.e., 1 g four times daily (group A, n = 131) and 2 g twice daily (group B, n = 128). Healing was defined as complete re-epithelialization. Clinical and endoscopic assessments were performed after four weeks (Day 28) and, if complete healing was not achieved, after four more weeks (Day 56). After four weeks, in group A (n = 114: eight patients were lost and nine were withdrawn), the ulcers had healed in 90 patients (79 percent), and in group B (n = 108: six patients were lost and 14 were withdrawn), the ulcers had healed in 80 patients (74 percent). The cumulative healing rates after eight weeks were 94 percent in group A and 95 percent in group B. No serious adverse effect was observed in either group. These results suggest that sucralfate tablets in a dosage of 2 g twice daily are as effective as 1 g four times daily in the treatment of acute duodenal ulcers and could lead to better patient compliance.

Mucosal coating agents and other nonantisecretory agents. Are they cytoprotective?

Gastric cytoprotection is protection against gross and histological gastric mucosal injury by a mechanism other than inhibition of neutralization of gastric acid secretion. Animal studies have shown that a variety of agents afford such a protective effect. With some of these agents, a similar protective effect has been shown in man. This protective effect must be distinguished from an action that enhances healing of an already established mucosal lesion as an ulcer. It is yet to be established that the cytoprotective effect of an agent enhances ulcer healing. Agents other than prostaglandins that have been shown to possess such a cytoprotective effect in animals are reviewed. Some, such as sucralfate, act via stimulation of endogenous prostaglandin synthesis, while others, such as DeNol, neomycin, and meciadanol, do not. Investigation of the mechanism through which these agents enhance gastric mucosal defense is a fertile field for investigation.

Urinary excretion of aluminium after ingestion of sucralfate and an aluminium-containing antacid in man

Eleven subjects with normal renal function were given, on 2 separate days, at least 1 week apart, four tablets of sucralfate or an aluminium (Al)-containing antacid. The total Al load was approximately 976 mg with the antacid and approximately 828 mg with sucralfate. The daily urinary excretion of Al was measured the day before and during 3 days after drug administration. Al excretion increased significantly after both drugs. There was no significant difference between the two products. The median absorption calculated as percentage of Al dose was 0.005% (range, 0.001-0.017%) for sucralfate and 0.006% (range, 0.002-0.060%) for the antacid. Thus, measurable quantities of aluminium is absorbed after administration of sucralfate, and the drug should, like Al-containing antacids, be given with caution to patients with renal failure.

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.

Developments in the treatment of peptic ulcer

A review is given of developments in the treatment of peptic ulcers from the early nineteenth century to modern times. 150 years ago long-term treatment consisted of antacids and dietary advice, while bed rest and starvation were included in most regimes around 1900. At the beginning of the 20th century the "Sippy regime" was adopted world wide, entailings, physical rest and complete neutralization of acid. The urge for complete elimination of acid led to the use of the continuous gastric drip. The side effects of these therapeutic modalities were considerable, and thus they were gradually abandoned, so that around 1950 only antacids and bed rest in the initial phase were recommended. During the last 20 years there have been dramatic developments in the medical treatment of peptic ulcers. The impact of the new drugs is discussed.

Gastric protection by sucralfate. Role of mucus and prostaglandins

Sucralfate promotes the healing of peptic ulcers and, in large doses, increases gastric mucosal prostaglandins. The present study was designed to further elucidate the protective effect of sucralfate and to evaluate the role of prostaglandins in this action. Eight chair-adapted rhesus monkeys received a subcutaneous injection of either 150 mg/kg of aspirin or vehicle in combination with either a therapeutic oral dose of sucralfate (50 mg/kg X day) or water. Gastric soluble mucus concentration was determined in samples of gastric juice by Alcian blue dye binding of acidic glycoproteins, and mucus output was determined using a technetium 99m-diethylenetriaminepentaacetic acid dilution technique. Monkeys underwent endoscopy to assess gastric mucosal damage, which was ranked blindly on a scale of 0-5, and to obtain biopsy specimens for determination of mucosal prostaglandin E2, prostaglandin F2 alpha, and 6-keto-prostaglandin F1 alpha. Aspirin did not alter soluble mucus but did significantly increase gastric mucosal damage and suppress tissue levels of all prostaglandins. Sucralfate significantly increased the output of soluble mucus, even after aspirin treatment, and protected against aspirin-induced damage, although it did not modify aspirin-induced suppression of prostaglandins. These results suggest that the gastric protection afforded by sucralfate is related to a prostaglandin-independent increase in mucus production.

Comparison of two sucralfate dosages (2 g twice a day versus 1 g four times a day) in duodenal ulcer healing

The effects of two dosage regimens of sucralfate, 2 g twice a day (one-half hour before breakfast and at night) and 1 g four times a day (one-half hour before meals and at night), on ulcer healing in 80 patients with endoscopically proved duodenal ulcer were compared. The study was single-blind and endoscopically controlled. Endoscopy was performed after four weeks and, if complete healing was not achieved, after an additional four weeks. Clinical assessment was carried out every two weeks. Seventy-four patients completed the study. After four weeks, the ulcer had healed in 28 of 36 patients (78 percent) who received 2 g of sucralfate twice a day and in 28 of 38 patients (74 percent) who received 1 g of sucralfate four times a day. The cumulative healing rates after eight weeks were 83 percent and 84 percent, respectively. The results suggest that sucralfate given in a dosage of 2 g twice a day is as effective as 1 g four times a day in the short-term treatment of duodenal ulcer.