The choice of ulcer healing agent influences duodenal ulcer relapse rate and long-term clinical outcome

The Success of Histamine-2 Receptor Antagonists

The lives of both patients and doctors have been revolutionized since the development of histamine-2 receptor antagonists. Their development has introduced, for the first time, a rapid, reliable, and save means of healing both duodenal and gastric ulceration. The continuous administration of these agents has additionally been shown to reduce ulcer relapse and subsequent complications. In addition, they offer some protection from the development of nonsteroidal anti-inflammatory drug-induced damage. The symptomatic relief of reflux together with healing of oesophagitis has been of further benefit. The drugs in this group have become one of the most widely used ethical pharmaceuticals in the world, with ranitidine (Zantac) as the biggest-selling drug in the world for the last few years. Their success can be attributed to their simplicity of use, safety, and above all, their efficacy. Their current role in gastroenterologic practice, in the face of new developments such as Helicobacter eradication and the development of proton pump inhibitors, will be discussed.

Long-term strategies for peptic ulcer

Commonly when treatment is stopped most peptic ulcers recur. The prevention of ulcer recurrence by continuous long-term therapy, usually with H2-receptor antagonists, provides effective and convenient management in patients at risk in order to reduce the chance of relapse, complications, and associated mortality. High relapse rates of peptic ulcer suggest the need for continuous H2-antagonists in elderly patients, those receiving NSAID, aspirin or anticoagulants, those with coexistent medical conditions and those with previous haemorrhage or perforation. Patients suitable for intermittent therapy include those who are < 60 years, with no previous ulcer complications, no coexistent medical conditions and few recurrences. Long-term H2-antagonists have an enviable safety profile and are cost effective. Despite this, the possibility of permanent cure of peptic ulcer by Helicobacter pylori eradication suggests that long-term therapy may not be needed. We face the exciting prospect of placing peptic ulcer into the annals of history.

Influence of initial therapy on outcome of peptic ulcer

Histamine 2 (H2) receptor antagonists, proton pump inhibitors, prostaglandin analogues, colloidal bismuth and sucralfate have all proved safe and effective in the initial treatment of peptic ulcer. Yet, most ulcers will recur when treatment is stopped. Continuous maintenance with H2 antagonists results in low symptomatic relapse, complications occur rarely, and such treatment is safe. An alternative is Symptomatic Self Care (on-demand therapy), which provides an economic option for patients with no concomitant disease or previous complications. Meta-analyses suggest a higher relapse rate after H2 antagonist therapy than that following sucralfate or bismuth. Whilst improved morphology and/or functional status of the gastro-duodenal mucosa ('quality of healing') has been claimed, the difference has not been explained. Successful prolonged eradication of Helicobacter pylori leads to a very low relapse rate, but more effective, predictable and safer eradication regimens are needed.

Quality of healing in peptic ulcer disease--are H2 receptor antagonists all we need?

The rapid relief of symptoms and ulcer healing can now be achieved in most patients with peptic ulcer. Histamine2 (H2) receptor antagonists, proton pump inhibitors, prostaglandin analogues, colloidal bismuth and sucralfate have all proved safe and effective for the initial treatment of peptic ulcer. However, most ulcers will recur when treatment is stopped. Meta-analyses suggest a higher relapse rate after H2 antagonist therapy than that following sucralfate or bismuth. This difference has not been explained although improved morphology and/or functional status of the gastroduodenal mucosa ("quality of healing") has been claimed. Eradication of Helicobacter pylori leads to marked reduction in relapse rate but more effective and safer eradication regimens are needed. Since most ulcers do recur, maintenance therapy with H2 antagonists remains a commonly used option. Continuous maintenance results in low symptomatic relapse, complications occur rarely, and such treatment is safe. An alternative is Symptomatic Self Care (on-demand therapy) which provides an economic option for patients with no concomitant disease or previous complications. Future research should decide the exact role of Helicobacter eradication; but for now, we can still rely on maintenance therapy with the widely-used and proven H2 receptor antagonists.

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.

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.

Clinical indications and efficacy of colloidal bismuth subcitrate

Colloidal bismuth subcitrate (CBS; DeNol) has been studied in clinical trials investigating the treatment of duodenal and gastric ulcer, non-ulcer dyspepsia, duodenitis, non-steroidal anti-inflammatory drug (NSAID)-induced disease, and Helicobacter pylori-induced gastroduodenitis. Healing rates for duodenal ulcer with CBS are significantly better than with placebo and are similar to results obtained with cimetidine or ranitidine. CBS is significantly better in the treatment of duodenal ulcer resistant to standard doses of H2 antagonists than increased doses of H2 antagonists. Duodenal ulcer relapse at 12 months after initial healing with CBS is significantly less than with H2-antagonist therapy. Ulcer healing with CBS is not influenced by smoking. H. pylori eradication with CBS appears to have little effect in ulcer healing but is of major importance in preventing ulcer relapse. CBS is effective in combination with antibiotics in eradicating H. pylori-associated gastritis. In gastric ulcer disease CBS therapy resulted in significant healing advantages over placebo and was comparable to treatment with cimetidine and sucralfate. CBS has been shown to be effective in the treatment of erosive duodenitis. The role of CBS in treatment of non-ulcer dyspepsia and NSAID-induced damage awaits further clinical studies.

Cost-effectiveness of alternative medications in the treatment of duodenal ulcer

This study examines the differential costs of various medications in the treatment of duodenal ulcer. Two approaches are taken. The first estimates the (differential) cost per year of life before relapse can be expected to occur, for five different medications. The second approach estimates the cost of treating a duodenal ulcer over a 5-year period during which ranitidine, cimetidine, or colloidal bismuth subcitrate (CBS) is used in the initial course of treatment. Expected rates of relapse and the probability of receiving maintenance therapy are taken into account. The results of both approaches suggest that CBS costs considerably less than other medications to achieve a similar outcome. It is concluded that, as well as the clinical benefits associated with slower relapse, the potential economic benefits of CBS are substantial.

Oxygen-derived free radicals and the prevention of duodenal ulcer relapse: a new approach

This study investigated whether or not oxygen-derived free radicals are implicated in the mechanism of recurrence of duodenal ulceration. To this end, allopurinol (50 mg qds)--a hydroxyl scavenger and an inhibitor of xanthine oxidase which forms superoxide radicals--and dimethyl sulphoxide (DMSO, 500 mg qds)--a hydroxyl scavenger--were given orally. Three hundred and two consecutive patients with previous symptomatic, endoscopy-proven duodenal ulceration which had been shown endoscopically to have healed and who were smokers and social drinkers, were randomized to receive for one year either placebo, cimetidine 400 mg at bedtime, allopurinol, or DMSO. In two hundred and twenty patients evaluable for efficacy, the cumulative relapse at one year was: placebo 65%, cimetidine 30%, allopurinol 12% and DMSO 13%. Cimetidine was significantly effective (p less than 0.01); however, allopurinol and DMSO were equally efficacious and superior to cimetidine (p less than 0.05). In patients who relapsed, the ulcer recurrence tended to occur early on placebo and to be evenly distributed over the year on active therapy. In all the groups, the relative frequency of symptomatic to silent relapses was similar in the first and second halves of the year and was comparable among the groups. The results suggest that oxygen-derived free radicals are directly implicated in the mechanism of duodenal ulcer relapse and that removing the radicals reduces recurrence of this ulceration.

The influence of a histamine2-receptor antagonist on the healing of an experimentally induced gastric mucosal lesion

The effect of an H2-receptor antagonist (ranitidine) on the healing of gastric mucosal lesions was studied. Mucosal lesions were induced by a standardized thermo-mechanical technique. The healing process was assessed by macro- and light microscopical examination. It was further evaluated by measurements of the tissue contents of hydroxyproline, a chemical compound reflecting collagen, and of DNA and RNA, reflecting cell frequency and protein synthesis respectively, in the gastric wall from both injured and wound-free areas. The healing process was more rapid in ranitidine-treated animals than in controls. After four weeks, however, the lesion in nine out of ten animals had healed in the ranitidine-treated group and seven of nine rats in the control group. At that time the amounts of hydroxyproline, DNA and RNA did not differ between the two groups. These findings may be taken as an indication that the tissue components of the healed lesions were similar in ranitidine-treated rats and in the saline controls, i.e. the different speeds of the healing process did not seem to influence the components of the scar tissue.

Carbonic anhydrase in the normal rat stomach and duodenum and after treatment with omeprazole and ranitidine

A low pH in the lumen of the stomach and duodenum stimulates gastroduodenal mucosal secretion of bicarbonate, particularly in the duodenum. Long-term deprivation of this acid stimulus might affect the ability of the mucosa to secrete bicarbonate, with a consequent decrease in mucosal protection against the acid. This could occur by 'down-regulation' of carbonic anhydrase (CA) activity in the bicarbonate-transporting cells. Levels of CA activity and amounts of CA isoenzymes in rat gastric and duodenal mucosa were determined by biochemical assay and histochemical and immunohistochemical staining. Control animals and animals pre-treated for 4-6 weeks with the histamine H2-receptor antagonist ranitidine (600 mg kg-1 daily) or the H+,K+-ATPase inhibitor omeprazole (28 mg kg-1 daily) were examined. Both drugs are potent inhibitors of gastric secretion of acid. Both gastric and duodenal mucosal total CA activity and the distribution of isoenzymes were very similar in control animals and animals treated with these drugs. In the stomach, CA II was found in the surface epithelial and parietal cells. In the duodenum both CA I and CA II were observed. The staining for CA I was restricted to a small number of villus cells which looked like ordinary duodenal enterocytes. CA II in the duodenum was found in all villus cells, except the goblet cells. The staining decreased gradually from the top to the bottom of the villi and was absent in the crypts. Duodenal bicarbonate secretion is dependent on mucosal CA activity, and the distribution of CA II thus suggests that this alkaline secretion is of villous rather than cryptal origin.

Initial therapy and relapse of duodenal ulcer: possible acid secretory mechanisms

Review of the four studies investigating the effect of initial therapy on ulcer relapse indicates that there is an increased rate of relapse after treatment with H2-receptor antagonists compared with placebo or other classes of drugs when combined. When individual drugs are considered, this appears to hold true for colloidal bismuth alone. There are several possible reasons for these differences. The most likely candidate mechanism to account for these differences is an alteration in gastric secretion, which might arise from alterations in gastrin, altered receptor regulation, parietal cell sensitivity, or peptic activity. However, the evidence for such an alteration in secretion is far from conclusive. Other factors that may be important include mucosal defense factors, smoking, Campylobacter pylori, and the statistical methodology.

Effect of omeprazole and ranitidine on ulcer healing and relapse rates in patients with benign gastric ulcer

Omeprazole blocks the action of H+,K+-ATPase in the gastric mucosa and thus inhibits the secretion of hydrochloric acid. We conducted a double-blind multicenter study (45 centers in 13 countries) of 602 patients with benign gastric or prepyloric ulcers to compare the effectiveness of omeprazole (20 mg once daily, 203 patients, or 40 mg once daily, 194 patients) and ranitidine, an H2-receptor antagonist (150 mg twice daily, 205 patients) in promoting ulcer healing and to evaluate the pattern of ulcer relapse during a six-month follow-up. Healing occurred at four weeks in 80 percent of the patients receiving 40 mg of omeprazole, 69 percent of those receiving 20 mg of omeprazole, 69 percent of those receiving ranitidine. At eight weeks, the corresponding figures were 96, 89, and 85 percent. A multivariate analysis of ulcer healing showed that at four weeks the ulcers of significantly more patients receiving omeprazole had healed as compared with patients receiving ranitidine (omeprazole, 40 mg, vs. ranitidine, P less than 0.0005; omeprazole, 20 mg, vs. ranitidine, P = 0.01). At eight weeks, the 40-mg dose of omeprazole was significantly more effective than ranitidine (P = 0.001) or the 20-mg dose of omeprazole (P = 0.03). Ulcer symptoms were relieved faster with omeprazole. In 68 patients receiving concurrent nonsteroidal antiinflammatory drugs, the healing rates at four weeks were 81 percent in the group receiving 40 mg of omeprazole, 61 percent in the group receiving 20 mg, and 32 percent in the group receiving ranitidine; at eight weeks, the corresponding figures were 95, 82, and 53 percent. During the six-month follow-up period (without treatment), significantly more patients in the omeprazole groups were free of symptoms and ulcers than in the ranitidine group. We conclude that in the dose used, omeprazole is superior to ranitidine in the treatment of benign gastric ulcers.

Colloidal bismuth in the treatment of duodenal ulceration: the benefit for the patient

Colloidal bismuth subcitrate (CBS) heals gastric and duodenal ulcers better than placebo and at rates similar to those observed with the commonly used H2-antagonists. Indeed, healing of duodenal ulcers may be more rapid than with cimetidine during the first month of treatment. When treatment is withdrawn, however, relapse is slower after CBS than after the H2-antagonists. The mechanism is uncertain but may be related to the ability of CBS to suppress Campylobacter pylori infection. The clinical implications of this difference in relapse rates are discussed. Preliminary data suggest that duodenal ulcer patients who are rendered C. pylori-negative for a prolonged period may be relatively immune to relapse. If confirmed, and if a suitably effective regimen can be found, this will transform the management of this difficult clinical problem.

Absorption and elimination of bismuth from oral doses of tripotassium dicitrato bismuthate

The pharmacokinetics of bismuth subcitrate were studied in plasma and urine under conditions of single and multiple dosing (28-56 days) using atomic absorption technique. Single dose plasma pharmacokinetics showed peak concentrations of 5.5-57.5 micrograms.l-1 (mean = 24.7 micrograms.l-1), reached between 30 and 60 min post dosing with an apparent biphasic elimination pattern. Multiple dose studies showed a continuing rise in plasma concentration and urine excretion rate reaching apparent steady-state levels over 7-29 days (mean = 18 days). Washout studies in 6 individuals reciprocated accumulation. Maximum equilibrated plasma levels of 7.6-58.3 micrograms.l-1 (mean = 38.3 micrograms.l-1) were well below those associated with encephalopathy. The half-life of bismuth elimination was 20.7 days. Present patterns of intermittent dosing with bismuth are unlikely to be associated with bismuth accumulation despite slow accumulation and elimination.

The potential impact of Campylobacter pylori on the treatment of duodenal ulcer disease

In most studies the association between Campylobacter pylori infection, Type B gastritis and duodenal and gastric ulceration is extremely strong. The best evidence for it having an aetiological role is at present in Type B gastritis. It should be remembered, however, that serological studies show carriage of the organism to be common also in the general population. An attempt is made here to gain some idea of the clinical impact of C. pylori infection in duodenal ulcer disease by analysing clinical trials, and in particular relapse data, in which an agent which suppresses C. pylori is used (colloidal bismuth subcitrate) and compared with one which does not (an H2-receptor antagonist). A mathematical model based on the data from these studies predicts that the prevalence of active duodenal ulceration will be twice as common in a group of subjects treated repeatedly upon relapse with an H2-receptor antagonist as in a group treated with colloidal bismuth. Other possible mechanisms are discussed but the ability of bismuth to suppress C. pylori infection is perhaps the best available explanation at present. Early data from several centres suggest that patients who can be rendered C. pylori negative over a prolonged period of time are relatively immune from relapse of their duodenal ulcers. If confirmed this observation may well transform the long-term management of duodenal ulcer disease.

Antacid maintenance therapy in the prevention of duodenal ulcer relapse

The effectiveness of antacid maintenance therapy in preventing duodenal ulcer (DU) relapse was investigated. Two hundred and fifty one asymptomatic patients with healed DU were stratified into smokers and non-smokers and randomised to receive for one year either placebo, or Maalox TC three tablets (81 mmol) at bedtime (hs), or Maalox TC three tablets in the morning plus three tablets at bedtime (bd) (162 mmol), or cimetidine 400 mg at bedtime. A double dummy technique was used to render the study double blind. In 176 patients evaluable for efficacy, the cumulative relapse at one year was: placebo 57%; Maalox TC hs 39%; Maalox TC bd 23%; cimetidine 25%. Maalox TC bd and cimetidine were equally effective and superior to placebo (p less than 0.01) and bedtime Maalox TC (p less than 0.04). The benefit of treatment was significant for the overall sample and for the subgroup of smokers. The results for the non-smokers also supported efficacy for these two treatments but, perhaps because of small sample sizes, these comparisons were not significant. All 251 patients were assessed for safety. Approximately half the patients in each treatment group had adverse events, leading to withdrawal in three, seven, 12, and four patients on placebo, Maalox hs, Maalox bd, and cimetidine respectively. Diarrhoea occurred in 12 patients in Maalox TC bd and eight in each other group. Serum magnesium concentrations were unchanged; aluminium concentrations were higher than baseline at six and 12 months in both antacid groups and at 12 months in the cimetidine group but the differences were not significant. Maalox TC three tablets bd are as effective as cimetidine 400 mg at bedtime in reducing DU relapse and both are superior to placebo.

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.

Histamine H2-receptor antagonists

The first histamine H2-receptor antagonists were developed in the early 1970s, and they have a dominant role in today's management of peptic ulceration. The original regimens using either cimetidine or ranitidine attempted to control acidity across the 24 hours, but more 'modern' regimens use a large single dose of the H2-blocker in the evening, which produces a pulse of decreased intragastric acidity during the night with a normal acidity in the daytime. High-dose regimens using a new generation of extremely potent histamine H2-receptor antagonists may improve ulcer healing rates at 4 weeks, and may be particularly useful for the management of either severe oesophagitis or intractable duodenal ulceration.

Are endoscopic and/or histologic findings in gastroduodenal mucosa a predictor of clinical outcome in peptic ulcer disease? A 1-year follow-up study after initial healing with either cimetidine or medium-dose antacid

Patients with duodenal ulcer (DU; n = 79) or prepyloric ulcer (PPU; n = 39) received cimetidine, 400 mg twice daily, or Novaluzid, 10 ml four times daily (acid-neutralizing capacity, 340 mmol/day), in a multicentre, randomized, double-blind trial. Ulcer healing was almost identical with the two treatments at 4, 6, and 12 weeks in the DU group. Cimetidine was significantly more effective than antacids in alleviating symptoms in PPU disease, with no significant difference in ulcer healing. In the PPU group the symptomatic improvement was inferior irrespective of treatment, and there was a significantly lower healing rate at 4 weeks (p less than 0.05) than in the DU group. The relapse rate over a 1-year follow-up period with no therapy did not differ between the two treatment groups or between the two ulcer groups. No factors in history of disease or endoscopic or histologic variables were of predictive value with regard to delayed healing. The macroscopic appearance of the duodenal and antral mucosae improved significantly when ulcers had healed. In the subgroup of about 50% DU patients who experienced a relapse during the 1-year follow-up period, the histologic scoring of duodenitis remained basically unchanged, contrary to the significant improvement seen in the non-relapsing subgroup. The microscopic changes of the antral mucosa from the time of inclusion to healing seen in the PPU patients were of no predictive value with regard to relapse rate.

Influence of ulcer healing agents on ulcer relapse after discontinuation of acute treatment: a pooled estimate of controlled clinical trials

Whether or not the incidence of ulcer relapse varies according to the drug used to produce initial healing is a controversial matter. We tackled this problem using data from 15 eligible trials from 25 published controlled trials in patients followed up for six to 12 months. Pooled estimates of differences in ulcer relapse incidence between patients initially healed with H2-antagonists and patients initially healed with non-H2-antagonist drugs were calculated. The overall incidence of relapse in patients healed with comparator drugs is 11 percentage units lower at six and 12 months, than that observed in H2-antagonist-healed patients. The confidence intervals are +/- 8% at six months and +/- 7% at 12 months. These data suggest the existence of a different effect on relapse incidence for the entire class of comparator drugs taken as a whole, compared with H2-antagonists. On considering the non-H2-antagonists singly, this conclusion holds good only in the case of tripotassium dicitrato bismuthate.

Relative effectiveness and costs of antiulcer medications as a basis for rational prescribing

To be maximally effective, antiulcer medications should relieve ulcer symptoms rapidly and promote rapid healing of an ulcer crater; after the cessation of a course of treatment the ulcer should not recur. A wide variety of agents is available. These are of similar efficiency in the control of ulcer symptoms and in the acceleration of the healing of the ulcer crater. However, evidence exists of differences in the rate of the recurrence of duodenal ulcers on the cessation of these drugs. Surface-active agents (bismuth complexes, sucralfate, prostaglandins and carbenoxolone) are consistently superior to H2-histamine receptor antagonist drugs (cimetidine and ranitidine). A high relapse rate produces more patients with active disease at any one time, hence more patients will be exposed to the complications of the disease, and will require active investigation and therapy. Because of the increased rate of relapse, the use of H2-receptor antagonist drugs as first-line intermittent healing therapy can be shown to be associated with an eight-fold (800%) increase in cost of pharmaceutical agents as compared with first-line treatment with bismuth salts; a four-fold increase compared with the cost of using antacid drugs; and a two-fold increase compared with the cost of using sucralfate. When maintenance therapy with H2-receptor antagonist agents is given instead of intermittent therapy with bismuth complexes, a 14-fold increase in pharmaceutical costs is incurred, with inferior results that have already been demonstrated under the conditions of a controlled clinical trial. These considerations of efficacy and cost suggest that H2-receptor antagonist drugs ought not to be first-line therapy for duodenal ulcers; rather, surface-active agents such as colloidal bismuth or sucralfate should be prescribed initially.

Campylobacter pyloridis, gastritis, and peptic ulceration

Campylobacter pyloridis is a spiral bacterium which was seen by histopathologists several years before it was cultured in 1982 in Perth, Western Australia. It has unique cellular fatty acids, predominantly tetradecanoic acid and cis-11, 12 methylene octadecanoic acid. It also has a unique ultrastructure which is different from that of other campylobacters. C pyloridis possesses a powerful urease enzyme and produces large amounts of extracellular catalase. Both these features may be important virulence factors, allowing it to occupy a protected niche in the stomach below the mucus layer but above the gastric mucosa. Specific lesions are found in the gastric mucosa, and ultrastructural studies show the presence of adherence pedestals identical with those found with enteropathogenic Escherichia coli of the intestine. Histological examination of gastric biopsy tissue has shown that C pyloridis is strongly associated with active chronic gastritis, when polymorphonuclear leucocytes are present, and is not found on normal mucosa except when a biopsy specimen from elsewhere in the stomach shows active chronic gastritis. When patients with symptoms caused by gastritis are identified dual antibacterial treatment, combining the action of bismuth in the stomach with a systemic antibiotic, can eradicate C pyloridis, with remission of symptoms and restoration of normal epithelial morphology. Most peptic ulcers relapse after modern acid reducing treatment, and antibacterial treatment may be beneficial in preventing relapse.

Cytoprotective agents and ulcer relapse

This study establishes that real differences between relapse rates exist, and confirmed previous observations by Pounder et al. that relapse rates influence clinical outcomes in ulcer populations.8 The results make it clear that the way in which a drug influences relapse is an important determinant of therapeutic efficiency, additional to the requirement for healing efficiency. Cytoprotective agents as a group appear to be associated with lower relapse rates than cimetidine. It si not known whether the differences are peculiar to cimetidine, specific to the blockade of H2-histamine receptors, or whether they relate to the process of inhibition of secretory processes generally, further comparisons are needed; however, conventional, clinical trials are not designed to provide the necessary information. For the healing of peptic ulcers, lower relapse rates appear to provide therapeutic advantage to members of the cytoprotective group when compared with agents acting via anti-secretory mechanisms, in addition to that associated with the local (non-systemic) mode of action where applicable.