Recurrent ulcer after treatment with cimetidine or sucralfate

Efficacy of omeprazole paste in the treatment and prevention of gastric ulcers in horses

Equine gastric ulcer syndrome (EGUS) is very common among performance horses, with a reported prevalence of approximately 90% in racehorses, and also > 50% in foals. Omeprazole, an acid pump inhibitor 5 times more potent than ranitidine, has been used with great success to treat EGUS. This multicentre study of Thoroughbred racehorses with endoscopically verified gastric ulcers was designed to demonstrate the efficacy of an equine oral paste formulation of omeprazole in the treatment and prevention of recurrence of EGUS. Of the 100 horses entered into the study, 25 were sham-dosed for the full 58 days of the study. The remaining 75 horses all received omeprazole paste, 4 mg/kg bwt/day once daily for 28 days. At Day 28, 25 of treated horses continued on this dosing regimen while 25 received a half dose (2 mg/kg bwt once daily) and 25 horses were sham-dosed. By Day 28, gastric ulcers were completely healed in 77% of omeprazole-treated horses, while 92% were significantly (P < 0.01) improved. In contrast, 96% of the sham-dosed horses still had gastric ulcers at Day 28. The improvement was maintained in horses that continued on either a full dose or half dose of omeprazole paste until Day 58. However, in those horses that were removed from omeprazole treatment at Day 28, the incidence and severity of the gastric ulcers at the end of the study were similar to those horses that did not receive the omeprazole paste. This study demonstrates that omeprazole paste, 4 mg/kg bwt per os, once daily, is highly effective in healing gastric ulcers in Thoroughbred racehorses and that either a full dose or half dose of omeprazole paste effectively prevents the recurrence of EGUS. The study also indicates that gastric ulcers in untreated horses did not demonstrate a significant rate of spontaneous healing.

Wound healing of acetic acid-induced gastric ulcer in rats and the effects of cimetidine and calcitonin, with special reference to prolylhydroxylase and collagenase enzyme activity

The healing of acetic acid-induced gastric ulcer in rats and the effects of cimetidine and calcitonin were investigated with reference to the enzyme activity of both prolylhydroxylase and collagenase as related to histological findings. The rats were observed by endoscopy on the 3rd day after the subserosal injection of acetic acid; rats with ulcers were divided into three groups: non-treated, and cimetidine- and calcitonin-treated. The latter two groups were treated for 7 days. Prolylhydroxylase activity in active ulcers in the non-treated group was slightly higher on the 3rd day and significantly higher on the 10th day than the activity in control rats that had received subserosal injections of physiological saline solution on the respective days. In non-treated rats, the healed ulcer on the 10th day showed lower prolylhydroxylase activity than that in the active ulcer on the same day. Cimetidine did not affect prolylhydroxylase activity, but, with calcitonin, there was higher prolylhydroxylase activity in the healed than in the active ulcer, although the difference was not significant. Interstitial collagenase showed the highest activity on the 3rd day and decreased on the 10th day in non-treated rats. Collagenase activity was higher in the cimetidine-treated group, than that in the non-treated group, and numerous peroxidase-positive granulocytes were seen in the mucosa and submucosa. Calcitonin did not affect collagenase activity. The participation of both enzymes is indispensable in the healing process and the effects of anti-ulcer agents on these enzymes must be considered.

Prevention of irradiation-induced bowel discomfort by sucralfate: a double-blind, placebo-controlled study when treating localized pelvic cancer

Sucralfate, an aluminum hydroxide complex of sulfated sucrose used in the treatment of gastric ulcer, was shown to prevent irradiation-induced diarrhea and bowel discomfort significantly in patients treated for pelvic cancer with external radiotherapy with intent to cure. The double-blind placebo-controlled study included 70 patients with carcinoma of the prostate and urinary bladder without distant metastasis (T1-4NO1xMO) and performance status of greater than or equal to 90% Karnofsky scale. Radiotherapy was administered in a conventional manner with MeV photons and a four-field technique. The total dose was 62-66 Gy and total treatment time of 6.5 weeks. Dose granules of sucralfate or placebo were dispensed to each patient 2 weeks after radiation started and continued for 6 weeks. All analyses were performed blindly. Seven of 34 evaluable patients in the placebo group and 18 of 32 evaluable patients in the sucralfate group did not present with diarrhea during the observation period. The frequency of defecation and stool consistency were significantly improved by sucralfate. Fourteen patients in the placebo group and only three in the sucralfate group required symptomatic therapy with loperamide. There was no evidence of adverse effects associated with the use of sucralfate. Sucralfate can be of beneficial value in diminishing the bowel discomfort during radiotherapy of pelvic malignancies, and the earlier proposed mechanisms of action (e.g., protection of denuded mucosa, cytoprotective properties, binding bile acids) can also be valid for the current effects of sucralfate.

Treatment of duodenal ulcer with sucralfate

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

Sucralfate in the treatment and prevention of gastric ulcer: multicentre double blind placebo controlled study

A randomised controlled multicentre trial was performed in 160 patients with gastric ulcer, proved by endoscopy and biopsy, to compare ulcer healing with sucralfate and ranitidine (double blind double dummy design) and to assess the effect of maintenance treatment with sucralfate on ulcer recurrence (double blind placebo controlled design). The healing rates were similar with 4 g sucralfate suspension per day and 300 mg ranitidine per day (82% and 88% after 12 weeks, respectively). Of the 109 patients with healed ulcers, 92 were entered into the maintenance trial and treated with sucralfate tablets (2 g per day) or placebo tablets. Maintenance treatment with sucralfate delayed symptoms of gastric ulcer recurrence. Lifetable analysis showed significant differences between sucralfate and placebo, both after six months (p = 0.018) and after 12 months (p = 0.044). The rates of symptom recurrences were 13% and 34% after six months and 34% and 55% after 12 months for sucralfate and placebo, respectively. The rate of asymptomatic recurrences after 12 months was similar in the two groups (9% and 10%, respectively). The recurrence rate was higher in patients who had never taken non-steroidal anti-inflammatory drugs than in those who had but had stopped on admission to the study. It was also higher in patients with recurrent ulcer and in those with scarring deformation and narrowing of the pylorus. Maintenance treatment with sucralfate slowed the appearance of symptom recurrences of gastric ulcer.

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.

Epidemiology in peptic ulcer disease. Current status and future aspects

Peptic ulcer incidence is declining. A decreased prevalence of smokers together with other factors have contributed to this change. The widespread use of non-steroidal anti-inflammatory drugs (NSAID) has increased the incidence of ulcer in the older population and serious complications, such as perforation and bleeding, have been observed especially in older women. Helicobacter pylori infection is virtually always present in duodenal and gastric ulcer and active chronic gastritis, but not prepyloric ulcer. The fact that this organism is not eradicated with the use of most drugs for peptic ulcer may explain the high rate of recurrence in ulcer disease since relapse rates are reported to be considerably lower when H. pylori is eradicated. In a substantial number of patients peptic ulcers are silent. These fall into two categories: the regular ulcer patient with relapses that heal spontaneously and rarely cause problems, and older patients without prior ulcer disease receiving NSAID treatment, presenting with a life-threatening complication as the first indication of ulcer disease. Despite all the new knowledge of peptic ulcer disease presented, the questions still outnumber the answers; it is therefore suggested that future research focus on the role of NSAIDs and H. pylori.

Increased serum pepsinogen I and recurrence of duodenal ulcer

To determine whether the serum pepsinogen I (PG I) level would be a suitable marker for selecting patients at risk for duodenal ulcer recurrence and, thus, would benefit from maintenance therapy, we treated duodenal ulcer patients with H2-receptor antagonists. After healing 140 ulcer patients we assessed the recurrence rate at 1 year with and without maintenance therapy. The annual recurrence rates in duodenal ulcer patients with hyper-PGI (95 ng/ml or more), with 66 ng/ml less than or equal to PGI less than 95 ng/ml, and with PGI less than 66 ng/ml were 87.0%, 27.3%, and 17.9%, respectively, when they did not receive maintenance therapy. In patients with hyper-PGI the recurrence rate was significantly lower in patients receiving maintenance therapy than in patients not receiving maintenance therapy, whereas in patients with PGI less than 66 ng/ml the recurrence rate was as low as 20% regardless of maintenance therapy. These results indicate that maintenance therapy with half the dose of H2-receptor antagonist is not required by patients with PGI less than 66 ng/ml, whereas those with hyper-PGI may be good candidates for long-term maintenance therapy.

Recent developments in the study of the effects of cigarette smoking on clinical pharmacokinetics and clinical pharmacodynamics

With the ever-increasing population of cigarette smokers, the potential for cigarette smoke to affect drug therapy both pharmacokinetically and pharmacodynamically is significant. The overriding pharmacokinetic effect is increased drug metabolism through the induction of liver enzymes. The constituents of tobacco smoke, primarily nicotine, have their own pharmacological effects which may potentiate or antagonise the desired pharmacological effect of a particular drug, thereby affecting its efficacy. Furthermore, end-organ responsiveness may also be altered by tobacco. These latter 2 aspects constitute altered clinical pharmacodynamics. Approximately 30 drugs have been evaluated in terms of cigarette smoking. Induction of liver enzymes has been shown to increase the metabolism of imipramine, meprobamate, oestrogens, pentazocine, phenylbutazone, theophylline and warfarin. Nicotine has been shown to inhibit diuresis, alter ulcer healing, impair subcutaneous absorption, affect protein binding and stimulate catecholamine release; these effects have been evaluated in terms of therapy with frusemide (furosemide), histamine H2-antagonists, insulin, lignocaine (lidocaine) and beta-blockers, respectively. The interactions have not been correlated with clinical significance in all cases. Diminished end-organ responsiveness may account for reduced drowsiness in smokers receiving chlorpromazine and benzodiazepines, compared with non-smokers. Smoking has been associated with diminished pain tolerance, requiring increased dosages of morphine, pethidine (meperidine) and propoxyphene. Enzyme-inducers such as carbamazepine, phenytoin and phenobarbitone appear to be minimally affected by cigarette smoke, perhaps because hepatic enzymes are already maximally stimulated. Codeine, corticosteroids and nortriptyline do not appear to be affected by cigarette smoke. The bioavailability of glutethimide is higher in smokers, but this has not been associated with greater efficacy. The effect of smoking on paracetamol (acetaminophen) has been variable, depending on the extent of smoking, and does not appear to be of clinical significance.

Implications of sucralfate-induced ulcer healing and relapse

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

Sucralfate and ranitidine in the treatment of acute duodenal ulcer. Healing and relapse. Ulcer Study Group

Healing and relapse of acute duodenal ulcer were investigated in an endoscopically controlled multicenter study using a double-blind design. Patients with acute uncomplicated duodenal ulcer were randomly assigned to treatment with sucralfate (1 g four times per day) or ranitidine (150 mg twice per day) for four to eight weeks. After healing, all anti-ulcer treatment was discontinued except for low-dose antacids needed for occasional upper abdominal pain, and the patients were observed for up to one year. Endoscopy was repeated after one year or at any time earlier if symptoms suggested ulcer relapse. Of the 83 patients who entered the study, 75 (sucralfate 40, ranitidine 35) underwent endoscopy after four weeks and could be fully evaluated. Healing rates after four and eight weeks were similar in the two groups (four- and eight-week healing rates after sucralfate and ranitidine: 78 and 74 percent, and 95 and 94 percent, respectively). Fifty-three patients with healed ulcers (sucralfate 29, ranitidine 24) were observed for up to one year. Duodenal ulcers occurred somewhat later after sucralfate than after ranitidine treatment, but life table analysis showed no significant difference. Thus, this study confirms a similar efficacy of sucralfate and ranitidine in healing of duodenal ulcer. A tendency to delayed relapse early after discontinuation of sucralfate failed to reach statistical significance.

Does the choice of acute treatment influence future ulcer relapse?

Despite the fact that the direct effect of drugs used for healing of ulcers does not last longer than hours, or at most a few days, some clinical studies have indicated that the rate of new ulcers after short courses of treatment depends on the drug used for healing. Several studies have now shown that the development of new ulcers in the same, regardless whether active ulcers have been healed with antacids or histamine H2-receptor antagonists. This lack of difference in clinical outcome is very likely true also for sucralfate and omeprazole in comparison with histamine H2-antagonists. A bismuth compound can perhaps prolong the period of clinical remission in a subgroup of patients in whom campylobacter pylori do not recur after finalized ulcer healing treatment. Other factors, i.e. smoking, and not the choice of ulcer healing drug, are of importance to recurrencies of new ulcers.

Clinical characteristics of roxatidine acetate: a review

Pharmacodynamic studies revealed that 150 mg of roxatidine acetate were optimal in suppressing gastric acid secretion, and that a single bedtime dose of 150 mg was more effective than a dose of 75 mg twice daily in terms of inhibiting nocturnal acid secretion. When administered orally as a capsule containing a granule formulation, the drug displayed modified-release properties, which led to a sustained suppression of gastric acid secretion. Clinical trials revealed that roxatidine acetate, 75 mg twice daily and 150 mg at night, was highly effective in healing duodenal and gastric ulcers and in reducing ulcer pain, over 4, 6, and 8 weeks of therapy. A steady reduction in diameter was observed in those ulcers not completely healed during therapy. The single bedtime dose regimen, while producing the same degree of healing as the divided daily dose during controlled clinical trials, may be of greater value in therapeutic use owing to improved patient compliance. In all efficacy criteria (cure, reduction in ulcer size, and pain relief) there was no significant difference between roxatidine acetate in a total daily dose of 150 mg, ranitidine in a total daily dose of 300 mg, and cimetidine in a total daily dose of 800 mg. Prevention of gastric and duodenal ulcer relapse was achieved by roxatidine acetate, 75 mg at night for 6 months, in about 70% of patients, as determined in open, pilot studies--a rate comparable to those reported for cimetidine and ranitidine. Roxatidine acetate shares with ranitidine an improved safety profile when compared with cimetidine. Human pharmacology studies and short-term and long-term clinical trials have all shown that roxatidine acetate is an exceptionally well tolerated compound, without the antiandrogenic activity and interference with hepatic drug metabolism which have characterized cimetidine treatment. A reason for the improved safety profile of roxatidine acetate may be its greater potency than cimetidine (six times less potent) and ranitidine (half as potent), so that lower doses of roxatidine acetate, representing a lower chemical load, are therapeutically effective. The novel structure of roxatidine acetate probably also underlies the improved safety of the compound.

Surgery is preferable in patients with severe chronic peptic ulcer disease

Conservative treatment given as interrupted courses is easy and successful for the majority of patients with peptic ulcer disease. For those plagued for years and years by severe chronic complaints the choice will be maintenance treatment or surgery. Maintenance treatment possibly spares the patient for an operation but includes a risk of stenosis claiming the necessity of a drainage operation with risk of sequels. The taking of the pill means a daily remembrance of the disease. Relapse rate is high. The economic problem is not unimportant for the patient. When contra indications are taken seriously into consideration modern ulcer surgery is not dangerous. There are no sequels if the pyloric function can be left intact. The cured patients feel fit and will usually forget the disease. Recurrence rate is lower than that during maintenance therapy but if occurring early they may be difficult to treat. The young patient with severe chronic duodenal ulcer disease should not wait eternally for a parietal cell vagotomy. When the ulcer is located to the pyloric channel prolonged conservative treatment may be advisable. Treatment policy for the gastric ulcer is debatable. No treatment is yet ideal. The advice to the individual patient should be based upon a non-prejudiced evaluation of the advantages and disadvantages of the therapeutic possibilities necessitating that the gastroenterologist and the surgeon have a thorough knowledge of the results of the other speciality.