Misoprostol clinical pharmacology. Establishment of activity in man

Misoprostol: A Quarter Century of Use, Abuse, and Creative Misuse

Misoprostol is a prostaglandin E1 analog originally intended for use to prevent NSAID-induced gastric ulcers. However, because of its cervical ripening and uterotonic property, misoprostol has become one of the most useful drugs in obstetrics and gynecology. Misoprostol has proven to be a very convenient and flexible drug because of its formulation as a tablet that is stable and that can be administered orally, rectally, vaginally and by the sublingual route. Beginning with its abuse for illegal abortion in the late 1980s, misoprostol has quickly become established as one of the most effective drugs for terminating pregnancies in the first and second trimesters, as well as for inducing labor in the third trimester. Its use for routine prevention of postpartum hemorrhage has not been so successful, partly as the high doses required for this indication often result in troublesome side effects. Despite the large body of medical evidence about its efficacy and relative safety, the use of misoprostol in pregnant women remained off-label until the spring of 2002.

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.

Misoprostol coadministered with diclofenac for prevention of gastroduodenal ulcers. A one-year study

The objective of this study was to determine the long-term efficacy of misoprostol in preventing diclofenac-induced gastroduodenal ulcers in rheumatoid arthritis and osteoarthritis patients. Three hundred eighty-four patients who had an endoscopically confirmed gastric or duodenal lesion that had healed with misoprostol therapy were randomized to receive misoprostol or placebo coadministered with diclofenac for up to 52 weeks. Endoscopic examinations were repeated at weeks 12, 24, and 52. The development of a gastric and/or duodenal ulcer was considered a prophylaxis failure. Results in the evaluable cohort of patients demonstrated that gastroduodenal ulcer incidences were lower with misoprostol than placebo for all study periods (0-12 weeks, 7% vs 23%; 0-24 weeks, 11% vs 26%; and 0-52 weeks, 15% vs 31%). Misoprostol did not interfere with the antiarthritic effects of diclofenac. In conclusion, misoprostol coadministered with diclofenac for 12 months to patients with rheumatoid arthritis or osteoarthritis significantly reduced the incidence of diclofenac-induced gastroduodenal ulcers (P < or = 0.018).

Effects of metronidazole and misoprostol on indomethacin-induced changes in intestinal permeability

In previous open studies, misoprostol and metronidazole reduced nonsteroidal anti-inflammatory drug-induced intestinal permeability changes and inflammation respectively. We assessed the effects of indomethacin treatment (50 mg three times a day) for one week with either coadministered metronidazole (400 mg twice a day, group 1, N = 9) or misoprostol (200 micrograms four times a day, group 2, N = 7) on intestinal permeability to [51Cr]EDTA and mannitol in healthy volunteers, using double-blind, placebo-controlled, randomized techniques. Given alone, neither metronidazole nor misoprostol affected [51Cr]EDTA permeation, whereas indomethacin alone increased it from 1.20 (0.40) [mean percent urinary recovery (SD) groups 1 and 2] to 2.43 (0.72), P < 0.002. Coadministered metronidazole (group 1) prevented this increase [1.10 (0.39) before, 1.55 (0.54) after, P > 0.05], whereas misoprostol (group 2) did not [1.31 (0.51) before, 3.26 (1.10) after, P = 0.005]. No drug regimen altered mannitol permeation. Indomethacin and misoprostol did not affect urinary recovery of intravenously administered probes. The results with metronidazole, if related to its antibacterial effects, support evidence from animal models that bacteria contribute to NSAID-induced intestinal damage. The previously reported reduction of indomethacin-induced increased permeability by misoprostol during a one-day study is not seen when the drugs are used in standard clinical doses for one week.

Renal effects of peptic ulcer therapy

Drugs used in the treatment of peptic ulcer disease may interact with the renal system in a variety of ways. Since many agents are eliminated by renal excretion, clearance of these agents may be reduced and half-life extended in the presence of renal insufficiency. The histamine H2-receptor antagonists may interfere with renal tubular excretion of creatinine and cationic drugs, resulting in elevated serum concentrations and reduced renal clearance. The prostaglandin E1 analogue misoprostol is used as a cytoprotective agent but has renal effects. The renal effects differ between systems studied. In the rat, misoprostol reduces cyclosporin-induced renal tubular toxicity, whereas in humans it has been shown to attenuate renal allograft rejection. Sucralfate is the aluminium salt of sucrose octasulfate. It permits the absorption of aluminium in amounts similar to aluminium-containing antacids, and toxicity has been demonstrated in the presence of renal insufficiency. Bismuth compounds are used increasingly to treat peptic ulcer disease, and bismuth toxicity has been described in association with renal insufficiency. Aluminium-, calcium- and magnesium-containing antacids are used as oral phosphate binders in patients with renal insufficiency in addition to their usual indications. Cation absorption and accumulation with all of these antacid preparations has been described and may lead to toxicity.

Management of gastroduodenopathy associated with use of nonsteroidal anti-inflammatory drugs

Adverse events associated with the use of nonsteroidal anti-inflammatory drugs (NSAIDs) are reported more frequently to the Food and Drug Administration than are those associated with any other group of drugs. The absolute risk for serious gastrointestinal events--in particular, ulcer bleeding, perforation, and death--is controversial; some investigators believe that an epidemic of NSAID-related complications is being experienced, whereas others suggest that the risks are being overemphasized. The management of patients who take NSAIDs regularly also remains controversial. Key unresolved issues include how best to identify those patients at particularly high risk for the development of ulcer complications and whether such patients should receive prophylactic therapy in an attempt to prevent such problems. In this review, we critically evaluate the currently available literature and present a management algorithm for the treatment and prevention of NSAID-associated gastroduodenopathy.

A double-blind comparison of the gastroduodenal safety and efficacy of diclofenac and a fixed dose combination of diclofenac and misoprostol in the treatment of rheumatoid arthritis

This double-blind, parallel group study was conducted to evaluate the gastroduodenal safety and antiarthritic efficacy of a fixed combination of diclofenac sodium 50 mg and misoprostol 200 mcg, compared with a combination of diclofenac 50 mg and placebo. Three hundred and thirty-nine patients with rheumatoid arthritis and no significant gastric or duodenal mucosal damage were enrolled and received study medication (diclofenac/misoprostol, 164; diclofenac/placebo, 175) BID or TID for 12 weeks. Posttreatment gastroduodenal endoscopic examinations revealed ulcers in 11% of the diclofenac/placebo group, compared with only 4% of the diclofenac/misoprostol group (p = 0.034). Four-weekly assessments of arthritic condition revealed no clinically or statistically significant treatment differences. It was concluded that diclofenac/misoprostol caused significantly less gastroduodenal damage than diclofenac, but was as effective as diclofenac alone in the treatment of rheumatoid arthritis.

Misoprostol: new frontiers; benefits beyond the gastrointestinal tract

Recent findings suggest that the protective role that misoprostol exerts in the gastrointestinal tract against nonsteroidal anti-inflammatory drug (NSAID) damage may be extended to a variety of other tissues and other noxious stimuli including those mediated by molecules such as interleukin 1 (IL-1), tumor necrosis factor (TNF), and endotoxin. The protective effects of misoprostol outside the gastrointestinal tract may involve prevention of triggering activities that would otherwise initiate a sequence of tissue damaging events. If this capacity of misoprostol to maintain homeostasis in a variety of settings is recognized, a cohesive pattern of action emerges. Numerous studies have shown that misoprostol is likely to act as a regulator within various cascades of immunological regulatory events. The in vitro and in vivo experimental data described in this paper suggest that the events which trigger episodes of pain and inflammation may be controllable by the administration of misoprostol. Mitigation of adverse effects of certain NSAIDs on renal function and cartilage metabolism has also been observed. Demonstration of this latter phenomenon in the clinical setting will greatly benefit the patient if it is shown to modify the arthritis disease process. The therapeutic applications of misoprostol beyond the gastrointestinal tract appear to be among the most interesting of therapeutic advances offered by any class of compound in the next decade. Because of the inflammatory and pain processes associated with arthritis disease progression, particular emphasis and confirmation through further clinical study should be placed on the potential effect of misoprostol on chondroprotection and synergy with NSAIDs.

Effects of four orally administered analogues of prostaglandin E1 and E2 on glucose tolerance and on the secretion of pancreatic and gastrointestinal hormones in man

Oral glucose tolerance tests (75 g, 300 ml) were performed in 12 healthy volunteers, with prior administration of placebo, misoprostol (400 micrograms), rioprostil (300 micrograms), enprostil (70 micrograms), or nocloprost (200 micrograms), in a double-blind, randomized manner. None of the drugs significantly affected glucose tolerance, although with misoprostal some volunteers displayed an impaired glucose tolerance. Nocloprost was without effect on gastric inhibitory polypeptide (GIP) and did not influence insulin or C-peptide concentrations. Misoprostol and rioprostil reduced integrated incremental responses of GIP by 57% (P less than or equal to 0.001) and 45% (P less than or equal to 0.01), respectively, and both gave rise to an initial (approximately 10 min) delay of insulin and C-peptide responses, without a significant overall reduction in integrated incremental responses. Enprostil almost totally inhibited the GIP response (by 94%; P less than or equal to 0.001), delayed initial insulin and C-peptide responses, but reduced the integrated incremental C-peptide response (which corresponds to the overall release of insulin) by only 14% (P less than or equal to 0.05). Enprostil more substantially reduced the integrated incremental response of insulin by 36% (P less than or equal to 0.01), and also reduced the ratio of insulin and C-peptide incremental responses (P less than or equal to 0.001). In conclusion, prostaglandin E analogues which caused a reduction in GIP responses, and thereby disrupting the enteroinsular axis to varying degrees, delayed the time-course of insulin secretion without a significant impact on glucose tolerance.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

Rioprostil in the short-term treatment of duodenal ulcer: a multicentre double-blind trial vs. cimetidine

The efficacy and safety of the new prostaglandin E1 (PGE1) synthetic analogue, rioprostil, 300 micrograms b.d. and cimetidine, 400 mg b.d., on duodenal ulcer healing are compared in an international, multicentre, double-blind study. A total of 257 patients have entered the study; 243 are considered eligible for efficacy analysis and 207 for safety analysis. After 4 and 6 weeks of treatment, the endoscopic healing rates do not significantly differ between the two groups, being 55% and 83% respectively with rioprostil vs. 60% and 78% respectively with cimetidine. The major adverse effect attributable to rioprostil is diarrhoea, which was documented in 11% of patients compared with 1% of patients taking cimetidine. However, central nervous system complaints are twice as frequent in the cimetidine group. Monitoring of clinical laboratory tests show no significant abnormalities when compared with the baseline values during the administration of either drug. This study documents that rioprostil, at the dosage of 300 micrograms b.d., is as effective and safe as cimetidine in the short-term therapy of duodenal ulcer.

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)

Twenty-four-hour intragastric measurements in twenty healthy subjects: effect of enisoprost, a novel and potent antisecretory and antipeptic synthetic E1 prostaglandin

Gastric aspiration was performed continuously overnight and at hourly intervals during the daytime in 20 healthy male volunteers. Medications used included enisoprost 100, 200 or 400 micrograms, misoprostol 200 micrograms and placebo, given at bedtime. Each dose of enisoprost markedly inhibited nocturnal mean acid output, hydrogen ion activity, pH and peptic activity. The duration of these effects was up to 10 h. Misoprostol, given at bedtime, also decreased acid secretion, but the effect was significantly less than that observed with any of the doses of enisoprost. A dose-response effect for enisoprost was found for the mean nocturnal hydrogen ion activity and pH, as well as for maximum pH attained. Although enisoprost, given at bedtime, had a marked inhibitory effect on acid and pepsin secretion for the overnight interval, this did not result in rebound hyperacidity or a rise in serum total gastrin concentration. The results of this study suggest that enisoprost should be tested by clinical trial for the treatment of peptic ulcer disease.

Dose-response, meal-stimulated gastric antisecretory study of prostaglandin E1 analog, misoprostol, in man

In a randomized, double-blind, crossover trial, the effects of 50-, 100-, and 200-micrograms doses of misoprostol on meal-stimulated gastric acid secretion were compared with placebo in 16 healthy male subjects. Compared with placebo, the 100- and 200-microgram doses produced significant reductions in acid output for 2 and 3 hr, respectively, following the test meal (P = 0.05). Misoprostol did not influence either the fasting or postprandial serum gastrin levels as compared with placebo. No adverse experiences were reported by any of the subjects. One subject experienced a transient rise in SGPT as compared with baseline, which may have been due to ethanol intake. This study provides a scientific rationale on which to base additional trials of misoprostol in patients with disease related to gastric acid production.

Evaluation of antisecretory activity of misoprostol in duodenal ulcer patients using long-term intragastric pH monitoring

The effect of the new synthetic prostaglandin E1 analog, misoprostol, on intragastric acidity was evaluated by means of 24-hr intraluminal pH monitoring of 16 duodenal ulcer patients. They were randomly allocated into two groups: eight received no medication and misoprostol 400 micrograms bid and eight received ranitidine 150 mg and misoprostol 400 micrograms bid not less than one week apart. The comparison of the 24-hr areas under the curve related to the median pH values showed that no difference existed between misoprostol and untreated patients in the first group, while ranitidine was significantly more effective (P = 0.00003) than misoprostol in the second group. The analysis of arithmetic differences between the 24-hr median pH values showed that misoprostol increased pH values by at least one unit compared to the untreated subgroup for about 3.5 hr, while the antisecretory action of ranitidine was far superior to that of misoprostol throughout the whole 24-hr period. It can be concluded that the effect of twice daily doses of misoprostol 400 micrograms on 24-hr intragastric pH is small and not at all comparable to that of the well-known potent H2 blocker ranitidine.

Protection by misoprostol against naproxen-induced gastric mucosal damage

The protective effect of misoprostol against naproxen-induced gastric mucosal damage was the subject of a double-blind, randomized, parallel-group study. Thirty-two healthy subjects were treated with naproxen 500 mg twice daily and either misoprostol 200 micrograms or matching placebo twice daily for seven days. Gastroscopy was performed before and after the treatment period and the mucosa was assessed for erosive and petechial lesions according to a predetermined scoring scheme. Of 25 evaluable subjects, 12 were treated with misoprostol and 13 were treated with placebo. The mean overall endoscopic score was 1.24 +/- 0.09 with placebo and 0.26 +/- 0.07 with misoprostol. The difference, 0.98, was highly significant (p less than 0.001), with 95 percent confidence limits of 0.74 to 1.22. All subjects in the placebo group had higher mean scores than any in the misoprostol group. The scores for erosive and bleeding lesions in the antrum and corpus/fundus of the stomach were all reduced by administration of misoprostol. In conclusion, the results clearly demonstrate that misoprostol protects the gastric mucosa of humans against naproxen-induced damage.

Comparative efficacy of misoprostol and cimetidine in the treatment of acute duodenal ulcer. Results of major studies

Misoprostol, a synthetic methyl ester of prostaglandin E1, has been shown to possess potent antisecretory activity in addition to a mucosal protective effect. Several multicenter double-blind, placebo-controlled trials confirmed the efficacy of misoprostol in the treatment of duodenal ulcer when administered at 800 micrograms in two or four divided doses daily. This report summarizes three cimetidine-controlled trials conducted in three separate geographic areas (Europe, Argentina, and Japan). The trials were double blind, randomized, and endoscopically controlled. In all studies, healing was defined as the absence of ulcer on endoscopy. The efficacy of misoprostol in the treatment of duodenal ulcer was shown to be equivalent to that of the histamine H2-receptor antagonist. In the Argentine study, the rate of disappearance of mucosal erosions was significantly greater for misoprostol than for cimetidine. Misoprostol was well tolerated. Mild and transient diarrhea not necessitating treatment or withdrawal occurred in 4 to 9 percent of the misoprostol-treated patients. These results indicate that misoprostol has a unique anti-ulcer action and represents a significant addition to the physician's armamentarium in the total medical management of duodenal ulcer.

Effects of misoprostol on human circulation

Prostaglandins (PGs) of the E-type are potent vasodilators in most species and in most vascular beds. However, vasoconstrictor effects of PGEs have also been noted at selected sites. This study examined the effects of misoprostol, a PGE1 analog with antiulcer activity, on the human cardiovascular system. Twenty healthy subjects participated in this double-blind, placebo-controlled, parallel group study. Following a 12 hour fast, heart rate, arterial blood pressure, light reflex plethysmography of the finger, resting blood flow volume in the lower arm and leg and peripheral vascular resistance were measured at 10 min. intervals for 1 hour prior to drug administration, to permit calculating baseline values. Misoprostol (400 mcg) or its matching placebo were administered orally, and the measurements were repeated at 10 min. intervals over the next 2 hours. A decrease in leg blood flow volume and a corresponding increase in leg peripheral vascular resistance were noted in the misoprostol group. A statistically significant decrease in heart rate between the two treatment groups was also noted. These small changes were not considered to be of clinical importance. No adverse experiences were reported. In conclusion, a single dose of misoprostol (400 mcg) has no clinically significant vasoconstrictive or vasodilative properties in man.

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 prevents damage to the gastric mucosa by stabilizing the mast cells

Prostaglandins have been shown to prevent the damage to the gastric and intestinal mucosa which has been induced by diverse necrotizing substances. These damaging stimuli increase the liberation of histamine from mast cells. Because of its well known effects on cellular permeability, histamine may serve the initial stimulus for mediating cellular damage. The aim of our study was to investigate the effect of misoprostol, a synthetic PGE1 analog, on tissue histamine concentration and mast cell counts after damage to the gastric mucosa induced by stress, histamine, aspirin and concentrated ethanol in guinea pigs. Misoprostol or its matching placebo were administered intragastrically 3 minutes prior to the ulcerogenic stimulus. After the induction of the injury, the animals were sacrificed, stomachs were examined for ulceration. Gastric and duodenal histamine concentrations were determined. Mast cells from these organs were stained and counted. All four ulcerogenic stimuli resulted in significant gastric ulcer formation. This ulcerogenic action was accompanied by a significant decrease in mucosal histamine concentration and mast cell counts. Misoprostol induced a dose-dependent inhibition of gastric damage, histamine depletion and mast cell destruction. These results indicate that the stabilization of mast cells by misoprostol is an important mechanism for its mucosal protective effects against ulcerogens.

Perspective on the gastric antisecretory effects of misoprostol in man

Misoprostol, a synthetic prostaglandin E1 analog, has been found to be safe and effective for the treatment of peptic ulcer disease. This brief overview summarizes the gastric antisecretory effects of misoprostol in healthy human subjects using randomized, double-blind, placebo-controlled studies. Misoprostol effectively and dose-dependently inhibited basal gastric acid secretion at single doses of 50, 100 and 200 mcg/subject. Furthermore, misoprostol effectively inhibited meal-, histamine-, coffee- and tetragastrin-stimulated gastric acid secretion. The inhibition of meal-stimulated gastric acid secretion was not a consequence of the reduction of serum gastrin. In addition, misoprostol inhibited nocturnal gastric acid secretion. In these studies, the titratable acidity, volume, acid output and pepsin activity were inhibited by misoprostol. The extent of the secretory inhibition achieved with the 200 mcg dose of misoprostol was comparable to that of cimetidine administered at a 300 mg dose. The duration of the gastric antisecretory actions was in the order of 3 to 5 hours. We conclude that misoprostol is a potent inhibitor of gastric acid secretion in man.

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.

Chronic antral gastritis in duodenal ulcer. Natural history and treatment with prostaglandin E1

The natural history of chronic antral gastritis in relation to the healing of duodenal ulcer and its response to treatment, if any, are unknown. We performed a double-blind controlled trial using an oral prostaglandin E1, misoprostol, in 229 patients with active duodenal ulcer randomized to receive placebo (n = 76), misoprostol 200 micrograms (n = 77), or misoprostol 300 micrograms (n = 76), q.i.d. orally. Healing of duodenal ulcer was assessed biweekly up to 12 wk by endoscopy, during which procedures at least two antral and two fundal biopsy specimens were taken. The activity and the degree of chronic inflammation of gastritis, as assessed histologically by the infiltration of polymorphs and chronic inflammatory cells, respectively, was graded blindly by two pathologists as nil, mild, moderate, or severe. Before treatment, 99% of patients had chronic antral gastritis and 1.5% had chronic fundal gastritis. In the placebo group, healed duodenal ulcer was associated with significantly (p less than 0.01, life table analysis) higher incidence of improvement of the activity of the antral gastritis (nil or mild as endpoint) than unhealed ulcer (30% vs. 4% at week 8). Irrespective of whether duodenal ulcer was healed or unhealed, significantly (p less than 0.01) more patients on misoprostol (50% at week 8) showed improvement (nil or mild as endpoint) than the placebo group. The degree of chronic inflammation of the antral gastritis showed similar significant changes in favor of misoprostol. Smoking and alcohol intake had no significant effect on the improvement of chronic antral gastritis. In conclusion, healing of duodenal ulcer was associated with improvement of the activity of chronic antral gastritis, which, as shown for the first time, could be further enhanced by a therapeutic agent--prostaglandin E1.

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

Chronic cigarette smoking adversely affects duodenal ulcer healing despite treatment by potent gastric acid-reducing agents. Prostaglandins of the E series possess antisecretory and cytoprotective properties and theoretically offer advantages over existing therapeutic agents. A double-blind randomized study was performed to compare complete duodenal ulcer healing as assessed by endoscopies every two weeks for up to 12 weeks. Two hundred twenty-nine patients were randomized to receive misoprostol, an orally stable synthetic derivative of prostaglandin E1, in 200-micrograms or 300-micrograms qid dosages, or placebo. Life-table analysis showed that (1) both regimens of misoprostol were significantly more effective than placebo, achieving healing rates of 61% and 71%, respectively, at four weeks, and (2) cigarette smoking significantly impaired healing by placebo but not by misoprostol. In fact, the time-healing curves of smokers and nonsmokers on the higher dose of misoprostol completely overlapped. Furthermore, delayed treatment and large ulcer diameter adversely affected healing by misoprostol in smokers, whereas in nonsmokers, high basal and maximal acid output were unfavorable. Misoprostol is recommended for the treatment of duodenal ulcer, particularly in chronic smokers early in a given period of symptoms.