Double-blind trial of cimetidine versus tri-potassium di-citrato bismuthate in chronic duodenal ulceration

Perforated Duodenal Ulcer and Cigarette Smoking

Whilst the association between smoking and peptic ulceration has been reported previously, the relationship between smoking and the complications of ulcers, such as perforation, bleeding or acute painful exacerbation, has not been examined. In a retrospective study comparing 275 emergency admissions for peptic ulcer with 275 controls, cigarette smoking was significantly more common only in those with a perforated duodenal ulcer. Of 128 patients with perforated duodenal ulcers, 110 (86%) were cigarette smokers compared with 65 (51%) of the 128 matched controls (χ2, P<0.01). Cigarette smoking in patients with bleeding or acutely exacerbated ulcers was not significantly more common than in controls. These findings strongly suggest a particular association between smoking and perforated duodenal ulcer.

What are the current possibilities in treating peptic ulcer disease?

There are two major principles of ulcer therapy. Today, the most widely accepted drugs are those which substantially reduce aggressive factors (i.c. acid and pepsin), namely histamine H2-receptor antagonists, antimuscarinics and antacids. Less frequently applied are mucoprotective agents like colloidal bismuth compounds and sucralfate. Prostaglandins both reduce acid secretion substantially and are believed to enhance mucosal resistance. Their anti-ulcer efficacy, however, is solely explicable by their antisecretory activity. Although mucosa-strengthening agents and H2-receptor blockers have nearly identical healing rates, mucosa-strengthening agents have inconvenient dosage regimens (four times or twice daily) and are probably less effective in relieving pain. The same holds true for antacids. Prostaglandins, antimuscarinics and antacids have dose related side effects. In contrast, H2-receptor blockers are characterized by a clear mechanism of action, convenient dosage regimens, good tolerance and a low incidence of side-effects. H2-receptor antagonists are the most effective anti-ulcer drugs presently available.

Comparison of plasma bismuth levels after oral dosing with basic bismuth carbonate or tripotassium dicitrato bismuthate

In 20 healthy subjects plasma bismuth concentration was measured after single oral doses of basic bismuth carbonate or tripotassium dicitrato bismuthate. The drugs were administered in the fasted state or immediately after ingestion of a standard breakfast. After basic bismuth carbonate, plasma bismuth rose to concentrations between 0.7 and 2.6 micrograms/L in the fasted state, while after the meal the maximal level was only 1.3 micrograms/L. In contrast to these very low levels after basic bismuth carbonate, the administration of tripotassium dicitrato bismuthate was paralleled by an increase of plasma bismuth to concentrations between 15 and 232 micrograms/L with a mean peak value of 64 +/- 15.3 (S.E.M.) micrograms/L in the fasted state. Postprandial ingestion of tripotassium dicitrato bismuthate attenuated the peak concentrations to 10.9 +/- 6.3 micrograms/L. One subject, however, had a value of 120 micrograms/L. This study demonstrates that basic bismuth carbonate leads to very low plasma bismuth concentrations, which are far below the critical range that might eventually be associated with bismuth neurotoxicity. Therefore this compound can be considered potentially useful for bismuth therapy of gastrointestinal disorders.

Bismuth therapy in gastrointestinal diseases

Bismuth therapy has shown efficacy against two major gastrointestinal disorders: peptic ulcer disease and diarrhea. In peptic ulcer disease it is as effective as the H2-receptor antagonists, costs considerably less, and offers a lower rate of relapse. When Helicobacter pylori is implicated, bismuth acts as an antimicrobial agent, suppressing the organism but not eliminating it. In recent studies, bismuth compounds have been used with conventional antibiotics, producing elimination of the organism, histological improvement, and amelioration of symptoms for periods longer than one year. Bismuth subsalicylate has shown modest efficacy in treating traveler's diarrhea and acute and chronic diarrhea in children, and it is effective prophylactically for traveler's diarrhea. An epidemic of neurological toxicity was reported in France in the 1970's with prolonged bismuth treatment, usually bismuth subgallate and subnitrate. Such toxicity has been rare with bismuth subsalicylate and colloidal bismuth subcitrate. However, recent studies have demonstrated intestinal absorption of bismuth (about 0.2% of the ingested dose) and sequestration of this heavy metal in multiple tissue sites, even occurring with conventional dosing over a 6-week period. These findings have inspired recommendations that treatment periods with any bismuth-containing compound should last no longer than 6-8 weeks, followed by 8-week bismuth-free intervals.

Colloidal bismuth subcitrate. A review of its pharmacodynamic and pharmacokinetic properties, and its therapeutic use in peptic ulcer disease

Colloidal bismuth subcitrate (CBS) possesses at least equal efficacy with histamine H2-receptor antagonist drugs in the treatment of peptic ulcer disease. However, CBS has the advantage of slower ulcer relapse rates than those seen after initial healing with the H2-antagonists. It has been postulated that this effect may be partly due to the antibacterial properties of CBS against Campylobacter pylori, a bacterium found in the gastric mucosa and gastric metaplasia within the duodenum of most patients with peptic ulcer and closely associated with gastritis. However, the role of C. pylori in the aetiology of peptic disease is far from clear. The mechanism by which CBS heals ulcers has not been fully elucidated, but several actions may be involved. CBS and mucus form a glycoprotein-bismuth complex in vitro. This provides a diffusion barrier to HCl and may, therefore, provide a protective coating in the ulcer crater which allows healing of the lesion to occur. Prostaglandin E2 production is also stimulated by CBS with subsequent secretion of alkali into the mucus layer. In addition, CBS has a direct inhibitory effect on C. pylori. Administration of CBS results in low levels of bismuth absorption. Most of the ingested bismuth is excreted as bismuth sulphide, causing blackening of the faeces, and the small amount absorbed is excreted in the urine. Bismuth intoxication (encephalopathy) has been reported with prolonged administration of bismuth salts, and there has been 1 report of similar intoxication in a patient receiving unusually high doses of CBS for a prolonged period. However, no such intoxication has been reported with CBS used at its recommended dosage in the acute treatment of peptic ulcer disease, and no other serious adverse effects have been associated with CBS. Tissue accumulation during prolonged therapy seems likely, and the safety of CBS during long term maintenance therapy has not been established. The lack of effect on gastric acid secretion is seen as an added advantage for CBS, since prolonged drug-induced hypochlorhydria has been postulated to have potentially detrimental effects. Thus, while the role of C. pylori in peptic ulceration requires further clarification, CBS would appear to have an important place in the treatment of peptic ulcer disease with the advantage of relatively slow relapse rates after initial healing and treatment discontinuation.

The role of colloidal bismuth subcitrate in the short-term treatment of duodenal ulcer

Colloidal bismuth subcitrate (CBS) is a drug used in the treatment of duodenal ulcer; it acts mainly by increasing mucosal resistance against endoluminal aggressive agents, without inhibiting gastric secretion. In previous clinical trials, CBS solution induced healing rates significantly higher than placebo and similar to those observed with cimetidine. In spite of these promising results, the drug has never been widely employed, mainly because of its unpleasant taste, which greatly reduced patient compliance. For this reason, chewing tablets have been introduced. CBS tablets have been reported to induce healing rates significantly higher than placebo and similar to those obtained with CBS solution, cimetidine, and ranitidine. CBS may therefore represent an important alternative to antisecretory drugs in the therapy of duodenal ulcer patients.

The influence of smoking on the healing of duodenal ulcer treated with oxmetidine or cimetidine

The influence of smoking on duodenal ulcer healing was examined during a double blind study of 83 patients randomly allocated to oxmetidine or cimetidine treatment. Smoking habits were recorded but patients were not advised to change these. Smokers and nonsmokers were similar clinically and did not differ in compliance with medication. Both H2-receptor antagonists were equally effective and after four weeks of treatment ulcers were healed in 76% of patients. Ulcer healing occurred significantly less frequently in smokers (69%) than nonsmokers (89%). Smokers with healed ulcers consumed fewer cigarettes per day (mean +/- SE: 15.8 +/- 1.4) than those whose ulcers did not heal (22.2 +/- 2.7). When smokers were grouped according to daily cigarette consumption, a direct relationship was found between increasing cigarette consumption and decreasing frequency of ulcer healing. No reduction in ulcer healing was apparent in patients who smoked nine cigarettes a day, or less.