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

The relationship between the control of pH and healing and symptom relief in gastro-oesophageal reflux disease

Gastro-oesophageal reflux disease (GERD) is generally considered to be the result of a motility disorder which permits the abnormal and prolonged exposure of the lumen of the oesophagus to the acidic gastric contents. This view is supported by experimental data, intra-oesophageal pH measurement, and the dramatic results of symptom relief and healing seen with effective antisecretory treatment. Oesophageal mucosal injury is determined by the pH of the refluxate and duration of acid exposure. Most patients experience meal-stimulated reflux during the day and the more severe cases experience 24-h acid exposure. In contrast to the H2-receptor antagonists (H2RAs), the proton pump inhibitors (PPIs) are more effective at controlling meal-stimulated acid secretion when each is given in standard doses. Therefore, the degree and duration of acid suppression throughout 24 h is greater. Treatments which maintain intra-oesophageal pH > 4 for 96% or more of the 24 h normalize acid exposure and are associated with the highest healing rates. Peptic activity is minimized at or above pH 4. The time above pH 4 is significantly longer with the PPIs than with the H2RAs. Thus, the healing-time curves for GERD (grades II-IV) are shifted to the left for the PPIs which heal a significantly greater proportion of patients earlier than the H2RAs or sucralfate. Symptoms in GERD are related to the degree and duration of oesophageal acid exposure. Symptom relief is more rapid and complete with the PPIs than with the H2RAs or other treatments in standard doses.

Prevention of gastric ulcer relapse induced by indomethacin in rats by a mutein of basic fibroblast growth factor

We found indomethacin aggravates healed gastric ulcers (ulcer relapse) in rats. In the present study, we examined the effects of human basic fibroblast growth factor (bFGF) mutein CS23 (TGP-580) and histamine H2-receptor antagonists (H2-RAs) on ulcer relapse in this model. In male SD rats, gastric ulcers were induced in the antrum by injection of acetic acid. Indomethacin (1 mg/kg/day) given s.c. for 2 weeks starting 4 weeks after the operation aggravated the healed ulcer; the areas with and without indomethacin were 4.8 +/- 1.4 and 0.4 +/- 0.3 mm2, respectively. Drugs were given orally once daily for 4 weeks starting 2 days after the operation or for the 2-week indomethacin administration period. Treatment with ranitidine (100 mg/kg), cimetidine (100 mg/kg) and TGP-580 (0.1 mg/kg) for 4 weeks accelerated the healing. The aggravation by indomethacin was significantly inhibited by pretreatment with TGP-580 and mildly inhibited by cimetidine but not ranitidine. When the drugs were co-administered with indomethacin for 2 weeks, the aggravation was significantly prevented by ranitidine and mildly inhibited by cimetidine and TGP-580. Both TGP-580 and H2-RAs can prevent the ulcer relapse induced by indomethacin but via different modes of action: TGP-580 inhibits relapse mainly by acting on the process of healing, while H2-RAs act mainly on the process of aggravation.

Effects of ranitidine on gastric vesicles containing H+,K(+)-adenosine triphosphatase in rats

BACKGROUND

To ascertain the mechanism for rebound acid hypersecretion after treatment with an H2-receptor blocker, we investigated the effects of ranitidine on gastric H+,K(+)-adenosine triphosphatase (ATPase) in rats.

METHODS

Male Wistar rats received ranitidine (1-50 mg/kg body weight intraperitoneally twice a day for 5 days). The rats were starved for 15 h after the last treatment and then killed, and gastric vesicles containing H+,K(+)-ATPase were prepared.

RESULTS

Treatment with ranitidine dose-dependently increased protein content in the gastric vesicular fraction purified from the gastric mucosa without changing total protein content. Ranitidine also increased the content of a 94,000-dalton protein, the catalytic subunit of H+,K(+)-ATPase. On the other hand, ranitidine did not affect the specific activity of the enzyme (mumol/min/mg of the gastric vesicular protein). Since gastric vesicles in the fasting state mainly consist of the tubulovesicular membrane, these results suggest that ranidine administration increases total tubulovesicular H+,K(+)-ATPase content (mumol/min/rat) by increasing the number of tubulovesicles per parietal cell. The ranitidine-induced increase in total tubulovesicular H+,K(+)-ATPase activity was still evident 1 week after treatment and returned to control level 1 month later.

CONCLUSIONS

All these findings suggest that the increased content and total activity of tubulovesicular H+,K(+)-ATPase after ranitidine treatment may contribute to the mechanism for acid rebound after H2-blocker therapy.

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.

Laboratory medicine in ulcer disease

The role of laboratory medicine in ulcer disease is poorly defined. However there is increasing evidence of the clinical usefulness of some laboratory tests that investigate secretory functions and defensive properties of the stomach, gastrointestinal hormones and Helicobacter pylori infection. These tests may modify the clinical management of patients with peptic ulcer by identifying H. pylori positive subjects, patients with high acid output, patients who do not respond to antisecretory therapy, and patients with high gastrin levels in whom Zollinger-Ellison syndrome may be suspected. Here we review the clinical value of laboratory tests in ulcer disease, particularly as concerns the cost/benefit ratio. The relative merits of these tests are described giving an indication of their possible role in the diagnostic algorithm.

Prospective, randomized, investigator-blind trial of Helicobacter pylori infection treatment in patients with refractory duodenal ulcers. Healing and long-term relapse rates

In this study, 26 patients with duodenal ulcers refractory to treatment with H2-receptor antagonists for 8-12 weeks were randomly assigned to eight weeks of treatment with colloidal bismuth subcitrate (120 mg four times a day) alone (N = 12) or in combination with tetracycline hydrochloride (500 mg four times a day, days 0-14) and metronidazole (500 mg three times a day, days 15-28). Symptoms were scored and endoscopy, histology, and CLO tests were performed before, on completion of treatment, and 3, 6, 12, and 18 months after treatment. Treatment was considered successful when Helicobacter pylori was not detected by CLO tests and Warthin-Starry stains on gastric biopsies taken from antrum, body, and fundus. On triple therapy, ulcers healed in 12/14 patients (85.71%) and 10/14 (71.42%) patients became Helicobacter pylori-negative. On bismuth, only one patient became Helicobacter pylori-negative (8.33%, P < 0.0001), but ulcers healed in 8/12 patients (67%, P = NS). Six patients on bismuth, whose ulcers remained unhealed or relapsed early after healing, were offered triple therapy, which resulted in ulcer healing in three and Helicobacter pylori clearance in two patients. At 18 months, none of the Helicobacter pylori-negative patients had ulcer relapse. On the contrary, ulcers relapsed in all but one patient, who remained Helicobacter pylori-positive. Smoking and drinking did not influence the therapeutic outcome. The data confirm previous reports that many duodenal ulcers are infectious and therefore curable.

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.

Importance of gastric acid in gastric ulcer formation in rabbits with antibody-induced prostaglandin deficiency

The role of gastric acid in the development of gastroduodenal ulcers in prostaglandin-deficient conditions is unclear. In the current study, the effect of the proton pump inhibitor omeprazole on the formation of gastric ulcers was examined in a previously validated rabbit model of antibody-induced prostaglandin deficiency. Intragastric administration of 20 mg/kg omeprazole every 12 hours caused a profound suppression of gastric acidity (i.e., pH above 5 continuously). This same dose of omeprazole significantly reduced gastric ulcer formation induced by passive immunization with 6-keto-prostaglandin F1 alpha antibodies. It is concluded from these observations that gastric acid plays a critical role in the formation of gastric ulcers in rabbits with antibody-induced prostaglandin deficiency.

Medical Therapy of Peptic Ulcer Disease

The gastric duodenal mucosa normally is protected from the damaging effects of gastric acid and pepsin by ill-defined mechanisms. Ulcers may arise when there is an imbalance between the aggressive and defensive factors that renders the mucosa susceptible to damage. A variety of factors have been identified that may favor the development of peptic ulcers, but no single pathophysiologic defect applies in all ulcer patients. In duodenal ulcers, gastric acid hypersecretion is observed in as many as one third of patients; however, most patients with duodenal ulcers secrete normal amounts of gastric acid. Decreased mucosal bicarbonate secretion may be important in at least some duodenal ulcer patients. Use of NSAIDs may cause either gastric or duodenal ulcers, probably through the inhibition of mucosal prostaglandin synthesis and disruption of mucosal defenses. Finally, a recently identified bacterium, H. pylori, causes a chronic gastritis that is found in the overwhelming majority of patients with duodenal ulcers and non-NSAID-associated gastric ulcers. This bacterium may play a pivotal role in ulcer pathogenesis and, especially, in ulcer recurrences. A number of drugs of proved efficacy are available for the treatment of acute duodenal and gastric ulcers. The H2 receptor antagonists administered once daily remain the mainstay of ulcer therapy because of their efficacy, ease of use, and excellent safety profile. More thorough and long-lasting acid inhibition is afforded by the H+/K(+)-ATPase inhibitor omeprazole. This agent also promotes more rapid ulcer healing, but in most patients, this minor advantage may not justify the higher cost. It is not known whether more rapid healing will translate into lower ulcer complication rates. Until further data are available, this drug may be preferable in patients with large or complicated ulcers. In patients with refractory ulcers, omeprazole is clearly superior to other available agents. Agents that promote mucosal defense mechanisms are becoming increasingly popular in the treatment of duodenal ulcers but have undergone less testing than in gastric ulcers. Sucralfate 1 g four times daily is equivalent to H2 antagonists in the treatment of duodenal ulcers and, probably, gastric ulcers. Its requirement for multiple daily doses makes it somewhat less attractive at present to most patients. Low- to medium-dose Al-containing antacids are inexpensive and efficacious in duodenal ulcer therapy. They should remain as therapeutic options for the compliant patient in whom cost considerations are important. Colloidal bismuth subcitrate 120 mg four times a day is comparable to other agents in the acute treatment of duodenal ulcers and likely gastric ulcers.(ABSTRACT TRUNCATED AT 400 WORDS)

Sucralfate diminishes basal acid output without affecting gastrin, H. pylori or gastritis in duodenal ulcer patients

Twelve patients with active duodenal ulcer disease and Helicobacter pylori infection were treated with 1 g sucralfate q.d.s. for 1 month. Ulcers healed in 8 of the 12 patients without an alteration in the H. pylori-associated antral gastritis. Sucralfate produced a significant fall in basal acid output in all the patients, from a median of 4.8 (range 2.1-12.1) to 1.6 (0.4-8) mmol/h, P less than 0.01, whereas peak acid output was unchanged from 41 (21-59) before to 38 (24-55) mmol/h after treatment. Basal plasma gastrin concentrations and the meal-stimulated integrated gastrin response were not altered significantly by sucralfate: 8 (2-17) pmol/L and 732 (188-1045) pmol. min/L pre-treatment and 6 (2-17) pmol/L and 600 (140-1302) pmol. min/L post-treatment, respectively. The fall in basal acid output observed may contribute to prolonged duodenal ulcer remission after treatment with sucralfate.

Tolerance during 5 months of dosing with ranitidine, 150 mg nightly: a placebo-controlled, double-blind study

Repeated dosing with an H2-receptor antagonist results in a modest decrease in antisecretory potency termed "tolerance." The object of this prospective study was to determine whether tolerance is a progressive phenomenon or whether it levels off during prolonged dosing with a standard maintenance dose of an H2-antagonist. The effect of continuous dosing with ranitidine, 150 mg nightly, was compared with intermittent dosing (27 days of placebo each month) with active ranitidine, 150 mg nightly, only on the night of each experiment. Simultaneous 24-hour intragastric acidity and plasma gastrin concentration were measured monthly for 5 months in 17 healthy subjects (7 continuous and 10 intermittent dosing). In the intermittent-dosing group, the antisecretory response to ranitidine, 150 mg nightly, was preserved throughout the 141-day trial period; the median nocturnal integrated acidity decreased from 557 mmol.h/L (day 0) to 38 mmol.h/L on day 1 of dosing, and it ranged between 32 and 55 (median, 45) mmol.h/L during days 29-141. In the continuous-dosing group, there was a significant return of nocturnal intragastric acidity on days 29 and 85 compared with day 1 of dosing. The median nocturnal integrated acidity decreased in the continuous-dosing group from 554 mmol.h/L (day 0) to 87 mmol.h/L on the first day of dosing, and it ranged between 145 and 287 (median, 170) mmol.h/L during days 29-141. Either intermittent or continuous dosing with ranitidine was associated with an elevation of plasma gastrin concentration, which remained constant throughout the 5-month study. Tolerance does develop in healthy subjects during the first month of dosing with ranitidine, 150 mg nightly, but it is not a progressive phenomenon, and it is probably not of clinical relevance.

Definition for idiopathic gastric acid hypersecretion. A statistical and functional evaluation

Zollinger-Ellison syndrome and other gastric acid hypersecretory states in which a specific etiology is identified are defined as a basal acid output of greater than 15.0 meq/hr. To determine the level of basal acid output that defines idiopathic gastric hypersecretion, basal acid outputs were investigated in normal subjects and patients with duodenal ulcers, and functional and statistical definitions for idiopathic gastric acid hypersecretion were developed. Sixty-five normal subjects were evaluated to define idiopathic gastric acid hypersecretion on a statistical basis, and 22 patients with refractory duodenal ulcers were evaluated to define idiopathic gastric acid hypersecretion on a functional basis. Mean basal acid output for the 65 normal subjects was 3.0 +/- 2.7 meq/hr. Even though the mean basal acid output for the group of 28 normal male subjects was slightly higher than for the group of 37 normal female subjects, the groups were not significantly different. The 95% confidence interval around the mean basal acid output for all normal subjects was 2.4-3.7 meq/hr, with little difference between the male and female groups. The mean basal acid output plus two standard deviations and the mean basal acid output plus three standard deviations for the 65 normal subjects were 8.4 meq/hr and 11.1 meq/hr, respectively. Of 109 patients with active duodenal ulcers treated for eight weeks with standard doses of antisecretory medication, 22 showed no healing as documented by endoscopy.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical efficacy of sucralfate in the treatment of gastric ulcer

We performed a randomized, single-blind study in Japan to investigate the efficacy and safety of two dosage regimens of sucralfate granules, 2 g, twice daily (b.i.d. group, n = 30) and 1 g, 4 times daily (q.i.d. group, n = 27), on ulcer healing in 57 patients with endoscopically proven gastric ulcer. Endoscopy was performed after 4 weeks and, if complete healing was not achieved, again after an additional 4 weeks. Of 57 patients, 11 were excluded from the statistical analysis because of protocol violation (six in b.i.d. group, five in q.i.d. group). Of 46 patients eligible for the analysis of healing rates, four patients in the b.i.d. group (all at 8 weeks) and five patients in the q.i.d. group (two at 4 weeks and three at 8 weeks) were withdrawn due to patients' inconvenience. As the possibility that the withdrawals were due to the treatment failures could not be denied, we used the Kaplan-Meier method and generalized Wilcoxon test/logrank test for the calculation and evaluation of healing rates in this study, respectively. Healing rates at 4 and 8 weeks were 50% and 94% in the b.i.d. group and 35% and 68% in the q.i.d. group. There was no significant difference in healing rates between the groups. No serious adverse effect was observed in either group. These results suggest that the 2 g b.i.d. dose of sucralfate in granule form is at least as effective as the conventional dose of 1 g q.i.d. in the treatment of active gastric ulcers and could lead to better patient compliance.

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.

Rebound hypersecretion after H2-antagonist withdrawal--a comparative study with nizatidine, ranitidine and famotidine

Our previous study demonstrated rebound nocturnal acid hypersecretion after a 4-week course of nizatidine. Nocturnal acid output was increased by 77% two days after discontinuing treatment compared with pretreatment values. To confirm this effect with other H2-blockers we assessed daytime intragastric pH, fasting and meal-stimulated plasma gastrin and nocturnal acid output in 9 duodenal ulcer patients in remission before, during and two days after treatment with three different drugs. Each patient received 4-week courses of 300 mg ranitidine, 40 mg famotidine or 300 mg nizatidine, taken at 20.00 hours in randomized order with a 'washout' period of 4 weeks between each course of drug. Median nocturnal acid output (mmol/10 h) decreased during treatment with ranitidine to 3 (range 0-17), famotidine to 4 (1-12) and nizatidine 6 (0-40) compared with the respective pre-treatment values, 49 (20-126; P less than 0.01), 52 (22-105; P less than 0.01) and 32 (23-114; P less than 0.01). Two days after discontinuing treatment nocturnal acid output was increased after ranitidine at 77 (28-237; P less than 0.04) and after nizatidine at 64 (17-130; P less than 0.05) compared with pre-treatment values. There was no significant change in nocturnal acid output after famotidine at 57 (27-107) compared with the pre-treatment value. There was no change in daytime intragastric pH with any drug during or after treatment compared with the pre-treatment values. Fasting and meal-stimulated plasma gastrin concentrations were increased on the final treatment day with ranitidine and famotidine but had returned to pretreatment levels two days after treatment. The rebound acid hypersecretion may contribute to the high ulcer relapse rate after discontinuation of H2-receptor antagonists.

Acute upper gastrointestinal bleeding in elderly persons

We have seen that UGI bleeding is a serious and apparently growing problem for seniors. Of special concern in the older patient are the frequency with which serious peptic disease presents silently, the limitation frequently imposed on adequate pain relief from NSAIDs, and the higher complication rates from most of the causes of UGI bleeding. Care of the elderly would be enhanced by research focused on defining those older patients most at risk of experiencing NSAID-induced peptic complications, improved methods for preventing or treating NSAID-induced ulceration that are well tolerated and cost-effective, and better regimens for preventing the recurrence of ulcers and UGI bleeding in these patients. In regard to the last, future investigation of the role of H. pylori, methods for successfully eliminating the organism, and the effect of eradication on patients' subsequent course may be particularly helpful.

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.

Helicobacter pylori, causation, change in natural history, and why Helicobacter-positive duodenal ulcers should not be routinely treated

The relationship between Helicobacter pylori and duodenal ulcer is reviewed with regard to the following epidemiologic issues: causation, change in natural history, and whether there is sufficient evidence to treat H. pylori-positive peptic ulcers routinely. There is mounting evidence for a pivotal role of H. pylori as a precipitating cause of duodenal ulcers. There is insufficient data to conclude that eradication of H. pylori alone will cure peptic ulcer disease--that is, preventing instead of controlling relapse. H. pylori-positive duodenal ulcers should not be routinely treated because eradication rates need to be improved, metronidazole resistance is an increasing problem, and side-effects of currently used triple combination treatments are substantial.

Cure of duodenal ulcer associated with eradication of Helicobacter pylori

50 patients with intractable duodenal ulcer were randomly assigned to 4 weeks of treatment with colloidal bismuth subcitrate (CBS) alone (26 patients) or with amoxicillin and metronidazole (24 patients). 5 patients (all on triple therapy) withdrew because of side-effects. In 17 of the 45 patients who completed the treatment, Helicobacter pylori was eradicated, and there was no ulcer relapse during the first 12 months of follow-up. The ulcer relapse rate was significantly higher (17 of 21 [89%]) among patients who remained positive for H pylori. 9 patients who remained positive for H pylori and had ulcer relapses within 6 months of treatment with CBS alone, were subsequently given triple therapy. 7 of the 9 showed H pylori eradication and no relapses within the next 12 months. The 2 patients still H pylori-positive after triple therapy had further ulcer relapses. H pylori eradication, without altering acid output, will become the mainstay of duodenal ulcer treatment because it cures the disease.