Prostaglandin E1 (misoprostol) overcomes the adverse effect of chronic cigarette smoking on duodenal ulcer healing

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.

Expression of oestrogen receptor and oestrogen-inducible genes in pancreatic cancer

BACKGROUND

Previous studies have not been able to demonstrate convincingly whether the human pancreas expresses oestrogen receptor and whether there is any benefit from antioestrogen therapy in advanced pancreatic cancer.

METHODS

Oestrogen receptor expression was assessed in normal human pancreas and pancreatic cancer tissue by enzyme immunoassay, Northern blot analysis, in situ hybridization and immunohistochemistry. The expression of the oestrogen-inducible proteins, progesterone receptor, pS2 and ERD5 was also examined.

RESULTS

A mean of 1.0 (range 0-2.4) fmol oestrogen receptor per mg protein was detected in normal pancreas and 0.5 (range 0-1.2) fmol mg-1 in pancreatic cancer. Messenger RNA for oestrogen receptor was detected in both normal and cancerous pancreas. In situ hybridization and immunohistochemistry, however, failed to localize oestrogen receptor expression. Mean (range) expression of progesterone receptor in normal and neoplastic pancreas was 1.9 (0.5-3.5) and 2.5 (0.3-9.3) fmol mg-1 respectively. pS2 and ERD5 were also expressed in normal tissue and pancreatic cancer, and expression was localized to ductular epithelium.

CONCLUSION

The amount of oestrogen receptor detected in pancreatic tissue was small, and may account for previous difficulties in its detection. The extent to which it is functional in both the normal and malignant pancreas warrants further investigation.

Can misoprostol and omeprazole reduce nicotine and ethanol induced gastric mucosal injury? A quantitative macroscopic and microscopic analysis in rats

We compared the effects of misoprostol, omeprazole and methylcellulose (control) on gastric mucosal injury induced by nicotine and/or ethanol. The results demonstrate that misoprostol and omeprazole each significantly reduce macroscopic injury and deep injury at a microscopic level (P < 0.05) induced by nicotine alone, ethanol alone or a combination of ethanol and nicotine. Misoprostol and omeprazole each reduced the leakage of fluorescein isothiocyanate-albumin into the interstitium in the gastric mucosa. Misoprostol and omeprazole are each effective in preventing injury induced by nicotine and ethanol and vascular factors are involved.

A comparison of two prostaglandin analogues (enprostil vs misoprostol) in the treatment of acute duodenal ulcer disease

We conducted a clinical trial to compare the efficacy and safety profile of two prostaglandin analogues, enprostil (35 micrograms twice daily) and misoprostol (200 micrograms four times daily) in the treatment of acute duodenal ulcers in 214 patients. The two agents healed approximately 80% and in excess of 90% of duodenal ulcers after 4 and 6 weeks' therapy, respectively. There was a significantly lower ulcer healing rate in both treatment groups in smokers compared with non-smokers (P < 0.05). However, daytime and nighttime ulcer pain relief was achieved in fewer than 50% of patients by either agent. Diarrhea, which occurred in more than 40% of patients, was the predominant side effect, and occurred mainly during the first 2 weeks of therapy with either agent. Nevertheless, this side effect was mild and self-limiting in the majority of patients. Both agents were found to be safe and well tolerated by the majority of patients. We conclude that these prostaglandin analogues are safe and effective duodenal ulcer healing agents. Furthermore, there was very little difference between enprostil and misoprostol. The limiting factors, however, for their routine use as ulcer healing agents are their low efficacy with regard to ulcer pain relief and the high incidence of diarrhea.

Society stress and peptic ulcer perforation

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

Review of the safety of diclofenac/misoprostol

The safety of a fixed combination of diclofenac 50mg/misoprostol 200 micrograms has been evaluated in clinical trials involving almost 2000 patients. Short term trials have been conducted in patients with osteoarthritis (n = 1032) and rheumatoid arthritis (n = 685) over 1 or 3 months. Patients randomly received either diclofenac alone or diclofenac/misoprostol. In both groups, the most frequently reported adverse events were gastrointestinal in nature, with abdominal pain reported most frequently (in 22.6% of patients receiving diclofenac/misoprostol and 19.8% of patients receiving diclofenac), followed by diarrhoea (19.5 vs 11.3%), nausea (11.0 vs 6.5%) and dyspepsia (10.6 vs 7.8%). The most frequent nongastrointestinal adverse event was headache, which occurred in 7.9% of diclofenac/misoprostol recipients and 9.3% of diclofenac recipients. Although diclofenac/misoprostol was associated with a slightly higher prevalence of adverse events than diclofenac in these studies, the majority were of mild or moderate severity, and the treatment groups were similar as regards the number of patient withdrawals resulting from adverse events. An interim analysis of the results of an ongoing trial of longer term administration of diclofenac/misoprostol (for up to 24 months) has been conducted. In this uncontrolled study, patients with rheumatoid arthritis, osteoarthritis or ankylosing spondylitis received diclofenac/misoprostol for up to 24 months; to date 1003 patients have been enrolled and treatment has been continued for 6, 12, 18 and 24 months in 640, 327, 108 and 13 patients, respectively. As in the short term trials, the adverse events reported most commonly in this study have been predominantly gastrointestinal.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of omeprazole on duodenal ulcer-associated antral gastritis and Helicobacter pylori

This study set out to investigate the effects of omeprazole or ranitidine on the progression of antral gastritis and Helicobacter pylori in patients with active duodenal ulcer. A double-blind, double-dummy trial was performed in 270 patients, 241 of whom were studied histologically for the presence of H. pylori. Patients were randomized to receive omeprazole, 10 mg every morning, omeprazole, 20 mg every morning, or ranitidine, 150 mg twice a day, for four weeks. Endoscopy was performed on entry and at weekly intervals during the study; at least two antral biopsies were taken on each occasion to assess the activity and degree of chronic inflammation, as reflected by the degree of polymorphonuclear leukocyte infiltration and mononuclear cell infiltration, respectively. Biopsy specimens also were assessed histologically for H. pylori. The sex, age and maximal acid output were comparable in the three treatment groups. The percentages of patients showing an improvement in the activity of gastritis in the four consecutive weeks of treatment were 9%, 40%, 51%, and 53% for omeprazole, 10 mg (N = 78); 14%, 42%, 49%, and 53% for omeprazole, 20 mg (N = 81); and 2%, 23%, 30%, and 33% for ranitidine, 150 mg twice a day (N = 82) (life table analysis gave P less than 0.01 for both omeprazole regimens compared with ranitidine). The degree of chronic inflammation showed similar changes. The density of H. pylori decreased significantly after treatment with omeprazole, 10 mg or 20 mg, (both, P less than 0.00001) but not with ranitidine.(ABSTRACT TRUNCATED AT 250 WORDS)

Pathogenetic role of Helicobacter pylori in duodenal ulcer disease. Multivariate analysis of factors affecting relapse

The pathogenesis of duodenal ulcer disease is multifactorial and the contribution of Helicobacter pylori in relation to the other factors to the release of duodenal ulcer is unknown. To investigate this, we studied 147 patients with endoscopically proven healed ulcers. These patients were randomized to receive either placebo, misoprostol 200 micrograms or misoprostol 300 micrograms four times daily, and clinical, personal, physiological and endoscopic characteristics were obtained prospectively. Endoscopy was performed at the active phase of the ulcer and when the ulcer healed. Biopsies were taken from the antrum to assess histologically for: (1) the activity of gastritis as assessed by the degree of polymorph infiltration, (2) the degree of chronic inflammation by the degree of chronic inflammatory cells infiltration and degree of mucosal degeneration, and (3) bacteriologically for the presence of H. pylori. The severity of the gastritis and the bacterial density were graded independently by two pathologists. The patients were assessed at two-month intervals for 12 months or until the ulcer relapsed. The results demonstrated that the relapse rates of duodenal ulcer were similar in the three treatment groups. The relapse rate was higher in the group with higher density of the bacteria (P less than 0.05). The degree of gastritis did not affect the relapse rate of duodenal ulcer in either the placebo or misoprostol group or in all patients combined. Stepwise logistic regression analysis identified that increased duodenal inflammation, male sex, early-onset disease, and H. pylori adversely affected relapse of the ulcer. We conclude that multiple factors affect the relapse of duodenal ulcer and H. pylori is one of them.

A double-blind study of misoprostol (SC-29333) in the healing of duodenal ulcer

In a double-blind randomized placebo controlled trial, 50 patients with endoscopically confirmed duodenal ulcer were treated with either misoprostol 200 micrograms or placebo in q.i.d. doses for 4-8 weeks. Of 25 patients in the placebo group, four defaulted and two were withdrawn due to worsening of symptoms. Of 25 misoprostol-treated cases, 17 cases (68%) and 21 cases (84%) healed at 4 and 8 weeks respectively, compared with three (14%) and five (24%) of the 21 placebo-treated cases (P less than 0.001). Except for diarrhoea in 2 patients in each group and itching in one with misoprostol, no serious side effects were noted.

Delirium in an elderly woman possibly associated with administration of misoprostol

Misoprostol has been associated with adverse reactions, including gastrointestinal symptoms, gynecologic problems, and headache. Changes in mental status, however, have not been reported. We present a case in which an 89-year-old woman in a long-term care facility became confused after the initiation of misoprostol therapy. The patient's change in mental status was first reported nine days after the initiation of therapy. Her delirium significantly improved after misoprostol was discontinued and her mental status returned to normal within a week. Because no other factors related to this patient changed significantly, the delirium experienced by this patient possibly resulted from misoprostol therapy.

Cigarette smoking, gastric acidity and peptic ulceration. What are the relationships?

The influence of cigarette smoking on intragastric acidity was assessed in duodenal ulcer patients in symptomatic remission and in healthy volunteers in a retrospective study. Continuous 24-hr pH recordings in 150 nonsmokers and 174 smokers receiving placebo treatment were compared. Daytime intragastric acidity was higher in smokers with a median pH (interquartile range) of 1.56 (1.34-1.80) than in nonsmokers, who had a median pH of 1.70 (1.45-1.97) (P less than 0.001). There was no difference in 24-hr and nighttime median pH between the two groups. The small difference in daytime intragastric acidity in smokers and nonsmokers is unlikely to account for the increased prevalence of peptic ulcer disease in smokers. The analysis of smoking status in duodenal ulcer patients and healthy controls and males and females supports the general trend towards higher daytime acidity in smokers. Again, no differences in pH during the 24-hr or night period were found between the groups. The epidemiological and clinical correlation between smoking and duodenal ulcer disease is not adequately explained by increased intragastric acidity.

The effect of misoprostol, omeprazole and sucralfate on nicotine- and ethanol-induced gastric injury and gastric mucosal blood flow: a comparative study

Nicotine, which is thought to be responsible for part of the pharmacological effect of smoking, exacerbates gastric mucosal injury in rats. The effects of misoprostol (12.5 micrograms to 100 micrograms), omeprazole (12.5 mg to 100 mg) and sucralfate (50 to 400 mg) on gastric mucosal blood flow and mucosal injury induced by nicotine were studied in an ex vivo gastric chamber preparation in rats. Rats were pretreated with nicotine (25 micrograms/mL orally) for 10 days and ethanol was added to the gastric chamber preparation. Laser Doppler flowmetry was used to measure the gastric mucosal blood flow and mucosal damage (ulcer index) was assessed by the area of haemorrhagic lesions. The ulcer index was significantly higher in rats pretreated with nicotine. Treatment with misoprostol and omeprazole lowered the ulcer index significantly compared with controls. The peak and summation blood flows were lower in nicotine-treated rats but failed to reach statistical significance. The peak blood flow (blood flow at 45 min) and the summation blood flow were significantly higher with all doses of sucralfate, misoprostol and omeprazole than in controls (P less than 0.05). The increase in gastric mucosal blood flow was significantly higher with sucralfate and misoprostol than with omeprazole. We conclude that sucralfate, misoprostol and omeprazole prevent nicotine- and ethanol-induced gastric mucosal damage and are accompanied by an increase in gastric mucosal blood flow. This indicates that smoking exacerbates gastric mucosal injury and that cytoprotective and site-protective agents can reduce injury by these noxious agents.

Influence of sex hormones on pancreatic cancer

A possible new approach to treating pancreatic cancer has been suggested, since the presence of estrogen receptors, estrogen binding proteins, estramustin binding protein, and androgen receptors have been demonstrated in human pancreatic adenocarcinomas of ductular origin. Moreover, there is some evidence that there is a dysfunction of the hypothalamic-sex-organ axis, resulting in low values of gonadotropins as well as testosterone in serum. Confirmatory evidence that all these findings have therapeutic implications in humans is still lacking, but in experimental studies, inhibition as well as growth potentiation of pancreatic cancer can be demonstrated after hormonal manipulations.

Misoprostol: discovery, development, and clinical applications

Misoprostol is a synthetic 15-deoxy-16-hydroxy-16-methyl analog of PGE1, and the first prostaglandin to be registered for the treatment of peptic ulcer disease. Misoprostol is a safe and well-tolerated drug that exerts potent gastric antisecretory effects and mucosal protective actions on the gastric and duodenal mucosa. In a dosage of 800 micrograms daily in two or four divided doses, misoprostol produced rates of complete ulcer healing in both gastric and duodenal ulcer patients significantly superior to placebo and comparable to H2 receptor antagonists. The major adverse effect is diarrhea in about 10% of patients, but this is usually mild and self-limiting. Misoprostol possesses uterotonic activity and should not be used in pregnant women or those who wish to become pregnant. Misoprostol effectively heals and prevents NSAID-induced gastropathy, a therapeutic need previously unserved. Due to its mucosal protective properties, misoprostol may have advantages over antisecretory drugs in the compromised patient who is a chronic smoker or alcohol user, in refractory duodenal ulcer patients, in recurrent ulcer, and in emergency use for acute upper GI bleeding. Misoprostol's tissue-protective effects may also extend to other therapeutic areas.

Prostaglandins and peptic ulcer therapy

The expectation that prostaglandin analogues would improve the ulcer healing abilities of other agents by combining mucosal protection with decreased acid secretion has been proved unwarranted. The ulcer healing capabilities of these drugs reflect their antisecretory potency. A role for these drugs in ulcer healing is questionable but their use has been advocated most strongly to prevent ulceration developing during treatment with non-steroidal anti-inflammatory drugs. While some evidence supports this role, an important clinical benefit of reducing complication rates has yet to be demonstrated.

Androgen influence on exocrine pancreatic cancer

Since the discovery of the first gastrointestinal hormones it has been intriguing to think that these defined chemical messengers may also influence the growth of tumors. Today, treatment with sex-hormones is well documented--and used in clinical practice--in prostatic (1,2), breast (3), endometrial, and ovarian carcinoma (4). Hormonal therapy (progesterone) has also been tried with some success in renal carcinoma (5,6). Nevertheless, cancers of the gastrointestinal tract--colorectal, liver, stomach, and pancreatic, carcinoma, which constitute 25 percent of all malignancies in Scandinavia--are only treated by other means, mainly surgery, although there is substantial evidence today that these tumors can also be influenced by hormones.

Misoprostol: a prostaglandin E1 analog with antisecretory and cytoprotective properties

Misoprostol, a methylester analog of prostaglandin E1, with antisecretory and cytoprotective properties, has undergone extensive investigation and has received Food and Drug Administration approval for the prevention of nonsteroidal-induced ulceration. The drug represents the first synthetic, orally active prostaglandin evaluated for the treatment of peptic ulcer disease. Clinical studies reveal a trend toward slightly lower healing rates with misoprostol when compared with histamine (H2)-receptor antagonists in the treatment of gastric and duodenal ulcers. In addition, misoprostol was less effective than H2-blockers in reducing ulcer pain, and caused a higher incidence of adverse reactions, particularly diarrhea occurring in up to 13 percent of the patients treated. Several studies have shown misoprostol to be superior to cimetidine and sucralfate in the prevention of alcohol- and drug-induced gastritis. This report summarizes the biopharmaceutics, pharmacokinetics, and clinical efficacy of misoprostol in the treatment of gastric and duodenal ulcers and in the prevention of mucosal injury.

Side effects of anti-ulcer prostaglandins: an overview of the worldwide clinical experience

Anti-ulcer prostaglandins (PG)--misoprostol, enprostil and rioprostil--have been given to more than 5000 patients in short-term studies on gastric and duodenal ulcer. Analysis of these studies shows the drugs to be safe. Their side effects appear to be dose-dependent and mainly restricted to the gastrointestinal system, the major syndromes being diarrhoea and abdominal pain. The clinical relevance of PG-related unwanted effects, though in average exceeding that of H2-blockers, seems to be sufficiently low. In terms of safety efficacy, however, they appear inferior to H2-antagonists, so their routine use in preference to the latter compounds is still premature.

Double-blind comparison of two dosage regimens of misoprostol in the treatment of duodenal ulceration

A multicenter double-blind study was conducted in 416 patients (306 male, 110 female) with active endoscopically proven duodenal ulcers who were randomly allocated to receive the prostaglandin E1 methyl ester analog (Misoprostol/Cytotec), either in a dose of 400 micrograms twice daily (206 patients) or 200 micrograms four times daily (210 patients). No significant difference in the healing rates between the two groups was observed at four or eight weeks. In patients treated twice daily, the ulcer healing rate at four weeks for the intent-to-treat cohort was 124/205 (60.5%) and for the evaluable cohort was 96/136 (69.1%). In patients treated four times daily, the healing rate was 124/207 (59.9%) for the intent-to-treat cohort and 96/148 (64.9%) for the evaluable cohort. Similarly, the healing rates achieved at eight weeks for the twice- and the four-times-daily dosages in the intent-to-treat cohort were 72.2% and 74.4%, respectively, and for the evaluable cohort were 88.0% and 86.6%, respectively. Significantly more patients receiving misoprostol twice daily were free of ulcer pain after four weeks of treatment than were those receiving misoprostol four times daily, namely, 71.4% as compared with 57.9%, respectively (P = 0.003) and for a median period of 21 as compared with 17 days (P = 0.002). Diarrhea was more common in patients receiving the drug twice daily, (15.5%) than in those treated four times daily (5%) (P = 0.001). Diarrhea, three or more stools daily, was often transient and self-limiting and only necessitated withdrawal from the trial in nine (4.4%) of those treated with misoprostol twice daily and in one patient (0.5%) of those treated four times daily.(ABSTRACT TRUNCATED AT 250 WORDS)

Prostaglandin treatment for peptic ulcer

Prostaglandin analogues have been expected to outperform other antisecretory drugs as ulcer healing agents. This expectation arises from their ability to combine 'cytoprotection' with gastric secretory inhibition. Evidence of the existence of these two separate functions abounds in animals and in humans, but a clinical advantage has not evolved. Whereas most clinical trials show no difference between prostaglandin analogues and H2-receptor antagonists, some studies have shown the prostaglandins to be significantly less effective or no better than placebo. The role of cytoprotection in ulcer healing (as opposed to prevention) may be questioned and the present clinical role for these agents is unclear.

Recent developments in peptic ulcer treatment

Since peptic ulcer disease is a multifactorial disease, the ideal therapeutic approach would be to use different drugs for different ulcers. In the past few years some studies have been published suggesting that subgroups of patients with peptic ulcer might particularly benefit from specific forms of therapy. In the present report the available evidence has been critically reviewed.

Antisecretory and mucosal protective actions of misoprostol. Potential role in the treatment of peptic ulcer disease

Misoprostol, a synthetic methyl ester analogue of prostaglandin E1, inhibits basal, nocturnal, and stimulated gastric acid secretion. In doses of 400 to 1,200 micrograms daily, misoprostol accelerates the healing of duodenal and gastric ulcers in humans. In addition to its antisecretory actions, misoprostol has gastroduodenal mucosal protective (cytoprotective) effects in animals and in humans. In humans, these cytoprotective actions have been demonstrated in acid-dependent studies using non-antisecretory doses and in acid-independent studies using antisecretory doses. Patients with peptic ulcer disease may have a relative deficiency of mucosal prostaglandin synthesis as compared with nonulcer control subjects. In addition, patients who consume nonsteroidal anti-inflammatory drugs and those who are cigarette smokers may also have depressed gastric mucosal prostaglandin synthesis. There is some evidence that misoprostol reverses the deleterious effect of smoking on duodenal ulcer healing and that it is effective in treating and preventing mucosal damage induced by nonsteroidal anti-inflammatory drugs and alcohol.

Humanitarian use of misoprostol in severe refractory upper gastrointestinal disease

Misoprostol was provided on a humanitarian basis to 157 patients with severe, often life-threatening, refractory upper gastrointestinal (UGI) disease not managed by available medical therapy (cimetidine, ranitidine, antacids, sucralfate, and/or prior surgery). A total of 162 separate clinical treatment courses were evaluated in the 157 patients for the period May 1, 1981 to May 6, 1986. Misoprostol was administered orally or via nasogastric tube, 800 micrograms to 1,200 micrograms daily in four to six divided doses, for periods of from one day to 17 months. Patients were considered to have a favorable clinical outcome if they achieved significant improvement in symptoms, hemorrhagic status, or appearance of their condition on endoscopy. Favorable clinical outcomes were observed in 52 of 83 treatment courses (63 percent) involving UGI hemorrhage and in 44 of 79 treatment courses (56 percent) for long-standing nonhemorrhagic UGI disease. A total of 116 treatment courses were for patients with a single UGI entry diagnosis; 28 treatment courses were for patients with two UGI entry diagnoses; four courses were for patients with three UGI entry diagnoses; and 14 treatment courses were for miscellaneous UGI entry diagnoses. Treatment outcomes were analyzed by the four most commonly treated UGI entry diagnoses; patients who had an initial diagnosis of refractory duodenal ulcer (n = 28), refractory gastric ulcer (n = 41), reflux esophagitis (n = 23), or hemorrhagic gastritis (n = 63) had favorable clinical outcomes of 71 percent, 58 percent, 61 percent, and 62 percent, respectively. Misoprostol was well tolerated, with the most common adverse experience being mild to moderate diarrhea. It is concluded that in humanitarian clinical trials, misoprostol was frequently associated with symptomatic relief, with improvement in UGI hemorrhage, or with endoscopic improvement in severe UGI disease that had proven refractory to available medical therapy.

Misoprostol in the treatment of duodenal ulcer refractory to H2-blocker therapy. A placebo-controlled, multicenter, double-blind, randomized trial

A multicenter, double-blind, randomized study compared 200 micrograms of misoprostol and placebo four times daily for four weeks in the treatment of 225 patients with duodenal ulcer (0.7 cm to 2.0 cm in size) persisting after at least four weeks of adequate, conventional therapy with cimetidine or ranitidine. Misoprostol was significantly superior to placebo in healing duodenal ulcers (achieving a healing rate of 37 percent versus 22 percent in the placebo group [p = 0.02], and in relieving ulcer pain [p = 0.01]). Healing also occurred more frequently with misoprostol than with placebo in patients with subgroups of particularly resistant ulcers. In the treatment of ulcers refractory to at least eight weeks of histamine H2-blocker therapy, misoprostol achieved a healing rate of 42 percent versus 20 percent with placebo. In the treatment of pyloric channel ulcers, 28 percent of patients in the misoprostol group showed healing as compared with 20 percent in the placebo group. Diarrhea was reported by 15.4 percent and 3.4 percent of patients receiving misoprostol and placebo, respectively, and was usually mild and transient. Misoprostol is safe and effective therapy for duodenal ulcers that have not healed during the course of H2-blocker therapy.

Sucralfate overcomes adverse effect of cigarette smoking on duodenal ulcer healing and prolongs subsequent remission

A unicenter, single-blind, randomized study was conducted on 283 patients with active duodenal ulcer to compare possible factors that may affect healing and relapse in patients treated with a potent antisecretory agent, cimetidine, or a site-protective and cytoprotective agent, sucralfate. The endoscopic healing rates at 4 wk were 76% and 79%, respectively, and cross-over treatment of the failures for a further 4 wk resulted in 68% healing with cimetidine and 69% healing with sucralfate, both differences being not statistically different. Unlike cimetidine, healing by sucralfate was unaffected by cigarette smoking, reluctance to give up smoking, habitual use of alcohol, high maximal acid output, and large ulcer diameter. In particular, the healing rate of smokers treated with sucralfate (82%) was significantly greater than that of smokers treated with cimetidine (63%). Duodenal bulb deformity significantly affected healing in both groups, and was the only offsetting factor identifiable for sucralfate out of 46 factors examined. Of the patients with healed ulcers, 238 participated in a 24-mo follow-up study consisting of interviews at 2-mo intervals and endoscopy at 4-mo intervals or whenever symptoms recurred. The cumulative relapse rate was significantly (p less than 0.007) greater in patients healed with cimetidine than with sucralfate, 50% relapse occurring at 6 and 12 mo, respectively. In both, the cumulative relapse rate was significantly greater in cigarette smokers than in nonsmokers, but smokers and nonsmokers treated with cimetidine relapsed (50% at 4 and 8 mo, respectively) faster than the corresponding smokers and nonsmokers treated with sucralfate (50% at 8 and 18 mo, respectively). Furthermore, in cimetidine- but not sucralfate-healed patients, early ulcer relapse (within 6 mo) was associated with short duration of illness, short remission period, long symptomatic spell, and reluctance to give up smoking. We conclude that smoking adversely affects duodenal ulcer healing by cimetidine and hastens subsequent relapse, and that sucralfate overcomes the adverse effect of smoking on healing as encountered with cimetidine, and results in a subsequent remission period double that of cimetidine.

Overview of the mucosal protective effects of misoprostol in man

Misoprostol, a novel synthetic analog of prostaglandin E1 has been evaluated for its potential mucosal protective properties in healthy human subjects using randomized, double-blind, placebo-controlled studies. Misoprostol significantly reduced established aspirin-induced gastric microbleeding. Likewise, misoprostol significantly inhibited aspirin-induced fecal blood loss when administered concurrently with aspirin. The reduction of gastrointestinal blood loss was neither a consequence of the inhibition of gastric secretion, nor a change in aspirin absorption. In addition, misoprostol effectively attenuated the transmucosal potential difference drop induced by sodium taurocholate. In endoscopic studies, misoprostol significantly inhibited damage to the gastroduodenal mucosa induced by aspirin, tolmetin and ethanol. In the ethanol study, the protective effects of misoprostol were significantly and profoundly greater than that afforded by cimetidine administered at an effective gastric antisecretory dose. These studies indicate that misoprostol has mucosal protective property in man. The basis for this mucosal protective effect is not fully known, but laboratory and clinical evidence indicate a direct effect on the barrier functions of the stomach, an increased or maintenance of gastric mucosal blood flow and an enhanced mucus and bicarbonate secretion. The implications of these findings suggest that misoprostol may be useful in the prevention and treatment of acute gastroduodenal mucosal lesions and inflammation.

Misoprostol. A preliminary review of its pharmacodynamic and pharmacokinetic properties, and therapeutic efficacy in the treatment of peptic ulcer disease

Misoprostol is an analogue of prostaglandin E1 and is the first synthetic prostaglandin analogue to be made available for the treatment of peptic ulcer disease. It inhibits gastric acid secretion in man, and there is also some evidence that it limits the extent of gastrointestinal damage induced by ulcerogenic agents in animals and healthy volunteers at doses lower than those required to inhibit acid secretion. This 'cytoprotective' activity has been explained by several mechanisms, but its contribution to the clinical efficacy of misoprostol in healing established ulcers is doubtful since the drug does not appear to be effective in healing peptic ulcers at non-antisecretory dosages. In clinical trials, ulcer healing has been reported in 60 to 85% of patients with duodenal ulcers and 32 to 54% with gastric ulcers receiving misoprostol 200 micrograms 4 times daily for 4 weeks--the recommended dosage. In comparative studies, the percentage of patients with healed ulcers after misoprostol (800 micrograms daily) was not significantly different from that with cimetidine (1200 mg daily), although there was greater pain relief with cimetidine. No study has yet been published concerning the use of misoprostol as maintenance therapy for the prevention of ulcer recurrence, and no long term tolerability data are available. However, in acute ulcer healing studies (2 to 12 weeks in duration) misoprostol has been well tolerated. Diarrhoea was the most commonly reported symptom, and this was only rarely of sufficient severity to interfere with treatment. No evidence of histopathological changes in the gastric mucosa induced by misoprostol have been reported in man. Evidence of uterine stimulant effects in women receiving misoprostol during the first trimester of pregnancy has resulted in the drug being contraindicated during pregnancy. Thus, misoprostol is a new type of antiulcer drug, providing an alternative approach to the therapy of peptic ulcer disease. It has been shown to be effective and well tolerated in the healing of both gastric and duodenal ulcers. Future studies need to identify the specific types of patients likely to obtain most benefit from treatment, in order to define more clearly the place of misoprostol in the treatment of these indications, as well as addressing the possibility of ulcer prevention with lower doses of misoprostol.

Misoprostol in peptic ulcer disease

Misoprostol, a synthetic prostaglandin E1 (PGE1) methyl ester analog has potent antisecretory and cytoprotective effects on the gastric and duodenal mucosa which should make it an effective drug in the treatment of gastric and duodenal ulcer. In two multicenter, randomised, double-blind, controlled studies involving over 900 patients with endoscopically proven benign gastric ulcer and in six similar studies involving over 2000 patients with active duodenal ulcers, differing doses of misoprostol have been compared with either placebo therapy or with conventional doses of cimetidine. In these studies misoprostol 800 mcg daily given as two or four divided doses has been shown to produce rates of complete ulcer healing and pain relief which were significantly superior to placebo therapy and comparable to those achieved with cimetidine. Drug related adverse effects were infrequent. A dose related diarrhea occurred in a small proportion of patients which seldom necessitated suspension of therapy. Because of the known uterotropic effect of prostaglandins the drug should not be used in pregnant women or women of child bearing age unless they are using adequate contraceptive measures. No clinically significant adverse, hematological or biochemical effects have been reported. Two studies suggested that misoprostol reduced the adverse effect of smoking on the healing of duodenal ulcer. In addition, misoprostol has been shown to protect the gastro-duodenal mucosa from the damaging effects of alcohol and non-steroidal anti-inflammatory drugs. This action may prove of value in the treatment of ulcer patients who are inveterate smokers, alcohol users or who are compelled to consume non-steroidal anti-inflammatory drugs for pain relief from rheumatic and allied diseases.

Prostaglandins and acid peptic disease: state of the art

A review of the new concepts concerning the regulation of acid secretion and the pathogenesis of peptic ulcer disease is presented. Advantages and disadvantages of the common pharmacological treatments are described with special emphasis on the drugs which represent, at present, the treatment of choice for peptic ulcer disease, namely, the histamine H2-receptor antagonists. The role of prostaglandins in health and disease is considered, and the possibility that synthetic compounds derived from natural prostaglandins represent a good alternative to the present medical management of peptic ulcer disease.

The role of arachidonic acid metabolites in gastrointestinal homeostasis. Biochemical, histological and clinical gastrointestinal effects

Metabolites of arachidonic acid have a broad range of physiological functions in the gastrointestinal tract, and seem to be involved in certain disturbances of gastrointestinal integrity and function. Prostaglandins inhibit gastric acid secretion, apparently via an adenylate cyclase-linked receptor, and also stimulate bicarbonate and mucus production by alternative mechanisms. These are all beneficial in treating gastroduodenal ulceration. Moreover, clinical studies have revealed deficient prostaglandin synthesis in the gastric and duodenal mucosa of patients with gastrointestinal ulcers, which suggests that endogenous prostaglandins have a protective role in the gastrointestinal tract. In animal studies, prostaglandin analogues have been shown to protect the gastric mucosa from damage induced by various potent irritants, and this protection seems to involve the deeper layers of the mucosa as well as the epithelium. Indeed, misoprostol and other prostaglandin analogues have proved therapeutically effective in treating gastroduodenal ulceration. Prostaglandins also influence intestinal motility and fluid movement. Prostaglandin E derivatives generally relax circular smooth muscle, contract longitudinal smooth muscle and increase fluid secretion into the intestinal lumen. As a result of these effects, prostaglandins may cause diarrhoea. There is also evidence that prostaglandin synthesis is increased in patients with diarrhoea. Finally, it has been reported that tissue concentrations of prostaglandins are increased in patients with ulcerative colitis, but it is unclear if this is a primary cause, or secondary event. Significantly greater conversion of arachidonic acid to its metabolites was recorded in the mucosa of patients with inflammatory bowel disease compared with the mucosa of healthy subjects. This included a substantial increase in the concentration of leukotriene B4.(ABSTRACT TRUNCATED AT 250 WORDS)

It is wise to prescribe NSAIDs with modern gastroprotective agents?

The administration of non-steroidal anti-inflammatory drugs (NSAIDs) leads to mucosal lesions in the upper gastrointestinal tract. Furthermore, NSAIDs increase the risk of ulcer bleeding and perforation, but the overall risk of fatal complications is relatively small (about 21 per one million prescriptions). Therefore, in asymptomatic patients, it is not justified to prescribe NSAIDs together with gastroprotective agents. The following recommendations can be given with respect to the management of peptic lesions in patients taking NSAIDs: (i) Fibre endoscopy should be performed even when there are relatively mild symptoms since mucosal lesions in rheumatic patients under NSAIDs produce minor or no symptoms. (ii) "Modern" NSAIDs might produce less gastric lesions than aspirin. (iii) Rheumatic patients with peptic disorders should be treated with an H2-antagonist. (iv) After complications such as ulcer bleeding or after rapid recurrence of peptic lesions, maintenance treatment with an H2-antagonist is advisable.

Stimulation of HCO3- secretion by the prostaglandin E2 analog enprostil: studies in human stomach and rat duodenum

This study investigated the action of enprostil, a synthetic analog of PGE2, on gastric HCO3- secretion in humans and on duodenal HCO3- secretion in the anesthetized rat. A previously validated 2-component model was used to calculate gastric HCO3- and H+ secretion in 10 human subjects. Compared to placebo, a single 70 micrograms oral dose of enprostil increased basal gastric HCO3- secretion from 1810 +/- 340 to 3190 +/- 890 mumol/hr (P less than 0.05). In addition, enprostil reduced basal gastric H+ secretion from 5240 +/- 1140 to 1680 +/- 530 mumol/hr (P less than 0.02). Enprostil also increased HCO3- secretion and reduced H+ secretion during intravenous pentagastrin infusion. In the rat, duodenal HCO3- secretion was measured by direct titration in situ using perfused segments of duodenum just distal to the Brunner gland area and devoid of pancreatic and biliary secretions. Addition of enprostil (10 micrograms/ml) to the duodenal bathing solution increased duodenal HCO3- secretion from 6.3 +/- 1.3 to 15.1 +/- 2.0 mumol/cm X hr (P less than 0.01, n = 6). The stimulatory action of enprostil on duodenal HCO3- secretion at 10 micrograms/ml was comparable in magnitude and duration to that of 10 micrograms/ml natural PGE2. In summary, the PGE2 analog enprostil stimulated gastroduodenal HCO3- secretion, effects which may be beneficial in protection of the gastroduodenal mucosa against luminal acid.

Prostaglandins for peptic ulcer: a promise unfulfilled

Prostaglandin analogues appear to heal peptic ulcers no better than would be predicted from their ability to inhibit acid secretion. This implies that their cytoprotective properties, which are so dramatic in acute animal experiments, play no part in ulcer healing. Ulcer healing involves mucosal repair, whereas cytoprotection concerns preservation of normal mucosa, the two processes being conceptually different. If any general benefits of prostaglandin cytoprotection are to be harnessed to clinical ends, drug delivery systems that ensure long-lasting contact with the gastroduodenal mucosa may be needed.

Prostaglandins in peptic ulcer disease. An overview of current status and future directions

Naturally occurring prostaglandins almost certainly play an important role in maintaining the integrity of the gastrointestinal mucosa. Clinical evidence available to date indicates that synthetic analogues of prostaglandins heal gastroduodenal ulcer only in doses that suppress gastric acid. However, non-antisecretory doses of prostaglandins may eventually have a role in the treatment of ulcer disease by maintaining ulcer healing and preventing recurrence. This possibility along with the potential of prostaglandins to prevent gastroduodenal mucosal injury caused by NSAIDs, alcohol, aspirin and stress, if supported by the results of ongoing clinical trials, may prove to be a major therapeutic advance for the treatment of acid peptic disease.

A multicenter international controlled comparison of two dosage regimens of misoprostol with cimetidine in treatment of gastric ulcer in outpatients

In this double-blind, parallel-group multicenter study, patients with endoscopically proven gastric ulcers were randomly allocated to treatment with either 50 micrograms or 200 micrograms of misoprostol or 300 mg of cimetidine, each given four times daily for four weeks. Endoscopic, clinical and laboratory assessments were made before treatment and after four weeks; clinical and laboratory assessments were repeated at two weeks. In the Korean center, assessments were also made after six weeks and at eight weeks of treatment. Six hundred and thirty patients were studied. The three treatment groups were similar in age and occupation. However, the proportion of men in the misoprostol 50-micrograms, 200-micrograms and cimetidine 300-mg groups was 67%, 63%, and 59%, respectively. Therapeutic success was defined as complete healing of all ulcers, judged endoscopically. On an intent-to-treat basis, which includes all losses to follow-up and withdrawals as treatment failures, ulcer healing rates in the misoprostol 50-micrograms, 200-micrograms and cimetidine 300-mg groups were 39%, 51%, and 58%, respectively. In the Korean center, the healing rates were 38%, 64%, and 70%, respectively, after eight weeks of treatment. There was no statistically significant difference in the healing rates at four weeks between the misoprostol 200-micrograms and cimetidine 300-mg groups (P = 0.16). The healing rate with the misoprostol 200-micrograms dose was significantly better than with the 50-micrograms dose (P = 0.008). Cimetidine 300 mg relieved global pain significantly better than misoprostol 200 micrograms at two weeks (P = 0.047) but not at four weeks.(ABSTRACT TRUNCATED AT 250 WORDS)

Therapeutic aspects of prostaglandins in the treatment of peptic ulcer disease

Studies of antisecretory compounds such as the H2-receptor antagonists have altered therapy and enhanced the understanding of peptic ulcer disease (PUD). While it is agreed that the dictum "no acid, no ulcer" is valid, acid hypersecretion does not appear to be the major determinant in a significant number of ulcer patients. More careful consideration of mucosal integrity in the pathogenesis of PUD is therefore necessary. A small but significant number of patients (5-15%) do not heal, despite the use of effective antiulcer drugs. Moreover, the posthealing recurrence rate may reach 75% after treatment is discontinued, and nearly one third of cigarette-smoking patients on maintenance therapy may suffer recurrences. Prostaglandins (PGs) are particularly important as potent antisecretory and effective antiulcer agents. In addition, recognition of their cytoprotective effects has stimulated research into the understanding and importance of mucosal protection and mucosal defense mechanisms. Animal studies show that PGs at nonantisecretory dosages prevent the development of gastric ulcers caused by virtually any insult. In humans, PGs prevent the mucosal damage caused by aspirin and ethanol. In some studies, the maintenance of normal mucosal integrity has been linked to normal mucosal production of PGs. Therefore, it is possible that exogenous PGs may be effective in patients whose ulcers do not heal with conventional therapy. They may reduce the recurrence of ulcers, particularly in those patients whose defect in mucosal integrity appears to be the major problem. Furthermore, in those patients subjected to the toxic effects of alcohol ingestion, nonsteroidal antiinflammatory drugs, antineoplastic drugs, and stress, exogenous PGs may prevent mucosal lesions. As such, PGs could be the ideal antiulcer drug.