A comparison of two different doses of omeprazole versus ranitidine in treatment of duodenal ulcers

Lansoprazole versus famotidine: efficacy and tolerance in the acute management of duodenal ulceration

Lansoprazole (AG 1749/CG 4801) is an inhibitor of gastric acid secretion by blocking H+,K(+)-ATPase. In this 2:1 randomized, double-blind, multicentre trial lansoprazole 30 mg am was compared to 40 mg famotidine nocte in 264 out-patients suffering from uncomplicated duodenal ulcer. After 2 weeks of treatment ulcer healing was confirmed endoscopically in a significantly higher proportion (P = 0.027) of patients treated with lansoprazole (94/174 = 54.0%) compared to patients receiving famotidine (35/90 = 38.9%). Cumulative healing rates after 4 weeks were 91.4% for the lansoprazole group and 83.3% for the famotidine group (P = 0.065). Pain relief and decrease of concomitant antacid consumption during treatment were comparable in both groups. Both compounds were well tolerated. Rates of recurrent duodenal ulcer in the 6 months after trial treatment were 45/158 (28.5%) after lansoprazole, and 18/69 (26.1%) after famotidine.

Comparative tolerability profile of omeprazole in clinical trials

The tolerability of omeprazole was compared to control agents in 68 clinical studies that enrolled a total of 4846 patients, of whom 3096 received omeprazole. The incidence of adverse experiences was independent of omeprazole dose administered, the age of the patients, and the disease treated (duodenal ulcer or endoscopically verified gastroesophageal reflux disease). The most common clinical adverse experiences were headache, diarrhea, abdominal pain, and nausea. The most common laboratory adverse experiences were elevated aspartate aminotransferase and elevated alanine aminotransferase. Omeprazole was well tolerated, and the incidence of clinical and laboratory adverse experiences was similar in patients receiving omeprazole, placebo, cimetidine, or ranitidine.

A comparison of omeprazole and ranitidine for duodenal ulcer in South African patients. A multiracial study

The study was a multicenter double-blind parallel-group comparison of omeprazole, a proton-pump inhibitor, with the H2-receptor antagonist, ranitidine, in 206 patients with duodenal ulcer. There were 145 men and 62 women of mixed racial origin with an average age of 40 years (range 19-76); 63 of them were white, 7 black, 135 coloured and 1 Asian. Each drug was given for four weeks and ulcer healing rate, symptom relief, and adverse events were recorded and compared between treatment groups. Patients received either 20 mg omeprazole once daily in the morning (N = 104) or ranitidine 300 mg once daily at night (N = 106). Healing rates were significantly higher in the omeprazole group than in the ranitidine group at both two weeks (80% vs 52%, P less than 0.001) and four weeks (95% vs 85%, P less than 0.05), using the "per protocol" approach, and these results were confirmed using the "intention to treat" approach. Omeprazole-treated patients reported significantly less daytime epigastric pain (P = 0.02) and heartburn (P = 0.04) after two weeks than ranitidine-treated patients. By four weeks, there were no significant differences in symptom reporting between groups. Both treatments were well tolerated, and there were no serious adverse events.

Omeprazole treatment does not affect the metabolism of caffeine

This study was performed to investigate the possible influence of repeated omeprazole dosing on the metabolism of caffeine, which has been shown to reflect the activity of one specific enzyme within the hepatic cytochrome P450 family, P450IA2. Ten healthy, nonsmoking young men participated in this placebo-controlled double-blind trial. Each subject was given omeprazole, 20 mg, every morning for 1 week and placebo every morning for 1 week in random order and separated by a 2-3 week washout period. On the sixth and seventh days of each period urine was collected twice daily, and urinary metabolites of caffeine were determined by high-performance liquid chromatography. The urinary metabolite ratio of three paraxanthine 7-demethylation products relative to a paraxanthine-hydroxylation product corresponds to caffeine clearance and, therefore, to P450IA2 activity. This calculated ratio was 4.8 (95% confidence interval, 3.9-5.6) in the placebo and 4.6 (95% confidence interval, 3.6-5.5) in the omeprazole period. These results show that the metabolism of caffeine was unaltered following omeprazole treatment, indicating that omeprazole treatment has no influence on cytochrome P450IA2 activity in the clinical situation.

Omeprazole drug interaction studies

This review examines the literature on drug interactions with omeprazole. Different mechanisms have been proposed as potential causes for such interactions. First, the absorption of some drugs might be altered due to the decreased intragastric acidity resulting from omeprazole treatment. There was no effect of omeprazole on the absorption of amoxycillin, bacampicillin and alcohol, while the amount of digoxin and nifedipine absorbed was increased by 10 and 21%, respectively, both increases probably being of no clinical significance. Secondly, the metabolism of high clearance drugs might be altered by changes in liver blood flow, although that is not affected by omeprazole, as indicated by the unchanged elimination of indocyanine green. In addition, the clearance of intravenously administered lidocaine (lignocaine) [a high clearance drug] was unaffected by omeprazole, further indicating that the latter does not alter liver blood flow. Thirdly, since omeprazole is a substituted benzimidazole, it might have the potential to interfere with the metabolism of other drugs by altering the activity of drug metabolising enzymes in the cytochrome P450 system, through either induction or inhibition. There is no indication of induction of this enzyme system in any interaction study with omeprazole. As regards inhibition, on the other hand, there is now considerable information available which indicates that omeprazole has the potential to partly inhibit the metabolism of drugs metabolised to a great extent by the cytochrome P450 enzyme subfamily IIC (diazepam, phenytoin), but not of those metabolised by subfamilies IA (caffeine, theophylline), IID (metoprolol, propranolol) and IIIA (cyclosporin, lidocaine, quinidine). Since relatively few drugs are metabolised mainly by IIC compared with IID and IIIA, the potential for omeprazole to interfere with the metabolism of other drugs appears to be limited.

Omeprazole

Omeprazole is a potent and effective antisecretory drug. Benefits in gastric and duodenal ulceration nevertheless seem marginal because standard treatments are very effective. More obvious advantages are discernible in oesophageal reflux disease where more profound acid inhibition may be needed to obtain symptom relief. Fears of important adverse effects either through inducing ECL cell hyperplasia or outright carcinogenesis, do not seem firmly founded, nor is there convincing evidence of significant interactions with other xenobiotics. Nevertheless, continued caution seems justified.

Pharmacokinetics of oral and intravenous omeprazole in patients with the Zollinger-Ellison syndrome

The pharmacokinetics and pharmacodynamics of oral and IV omeprazole after a single dose were studied in 9 patients with the Zollinger-Ellison syndrome to determine whether the increased dose required to control gastric acid hypersecretion could be explained on the basis of altered pharmacokinetics. Each patient was studied both after receiving a single IV bolus of omeprazole (40 mg) and after receiving a single oral dose of omeprazole (80 mg). Intravenous and oral omeprazole doses were administered 1 week apart. Gastric acid secretion and plasma concentrations of omeprazole after drug administration were determined in each patient. The area under the plasma concentration curve, clearance, and volume of distribution after IV omeprazole administration and the area under the plasma concentration curve, peak plasma concentration, and time required to reach the peak after oral omeprazole administration were not different from those reported previously for normal subjects and patients with peptic ulcer disease. Mean (+/- SEM) bioavailability of oral omeprazole for all patients was 68% +/- 16%, which was similar to the bioavailability reported previously for normal subjects. Three patients had a significantly lower bioavailability reported previously for normal subjects. Three patients had a significantly lower bioavailability (20% +/- 8%) than the others, and their basal acid outputs were significantly higher than those of the other 7 patients. For all patients there was an inverse correlation between bioavailability and basal acid output (r = 0.76; P less than 0.02). The mean (+/- SEM) elimination half-lives of IV and oral omeprazole were not different (2.3 +/- 0.4 vs. 2.4 +/- 0.5 hours) but were significantly longer than those reported previously for normal subjects (P less than 0.02). The duration of action correlated with the elimination half-life of the drug (r = 0.87; P less than 0.003) and area under the plasma concentration curve (r = 0.72; P less than 0.03). The mean durations of action of IV and oral omeprazole were not significantly different (34 +/- 7.2 vs. 35 +/- 6.2 hours). It was concluded that altered pharmacokinetics do not account for the increased drug requirement of omeprazole in patients with the Zollinger-Ellison syndrome. In contrast to a previous study, the oral and IV omeprazole had the same duration of action, suggesting that intermittent bolus administration of parenteral omeprazole will obviate the need for continuous infusion of histamine H2-receptor antagonists in patients requiring parenteral antisecretory drugs. Furthermore, an IV dose every 12 hours controlled acid secretion in all patients, suggesting this as the recommended dose interval in patients requiring parenteral drug therapy.

Omeprazole. An updated review of its pharmacology and therapeutic use in acid-related disorders

Omeprazole is the first of a new class of drugs, the acid pump inhibitors, which control gastric acid secretion at the final stage of the acid secretory pathway and thus reduce basal and stimulated acid secretion irrespective of the stimulus. In patients with duodenal or gastric ulcers, omeprazole as a single 20 mg daily dose provides more rapid and complete healing compared with ranitidine 150 mg twice daily or 300 mg at nighttime, or cimetidine 800 or 1000 mg/day. Patients poorly responsive to treatment with histamine H2-receptor antagonists respond well to omeprazole--most ulcers healed within 4 to 8 weeks of omeprazole 40 mg/day therapy. Omeprazole 20 or 40 mg/day has been administered as maintenance therapy for peptic ulcer disease for up to 5.5 years with very few ulcer recurrences. In patients with erosive or ulcerative oesophagitis, omeprazole 20 or 40 mg/day produces healing in about 80% of patients after 4 weeks, and is superior to ranitidine with respect to both healing and symptom relief. Healing rates of greater than 80% are achieved after 8 weeks in patients with severe reflux oesophagitis unresponsive to H2-receptor antagonists. Maintenance therapy with a daily 20 mg dose prevents relapse in about 80% of patients over a 12-month period. Omeprazole is considered to be the best pharmacological option for controlling gastric acid secretion in patients with Zollinger-Ellison syndrome. Daily dosages of 20 to 360 (median 60 to 70 mg successfully reduce basal acid output to target levels (less than 10 mmol/h or less than 5 mmol/h in patients with severe oesophagitis or partial gastrectomy) during treatment for up to 4 years. Omeprazole is well tolerated in short term studies (up to 12 weeks); the reported incidence of serious side effects (about 1%) being similar to that seen in patients treated with an histamine H2-receptor antagonist. The longer term tolerability of omeprazole has been investigated in patients treated for up to 5.5 years. Slight hyperplasia, but no evidence of enterochromaffin-like (ECL) cell dysplasia or neoplasia or ECL cell carcinoids has been reported. ECL cell carcinoids have been observed in rats after life-long treatment with high doses of omeprazole or ranitidine, or in rats with partial corpectomy; the weight of experimental evidence indicates that this is a result of prolonged hypergastrinaemia.(ABSTRACT TRUNCATED AT 400 WORDS)

Omeprazole in elderly duodenal ulcer patients: relationship between reduction in gastric acid secretion and fasting plasma gastrin

The effect of omeprazole on acid secretion and gastrin levels has been investigated in 10 elderly duodenal ulcer patients in remission. Doses of 5, 10, 20 and 40 mg omeprazole were given once daily for 7 consecutive days and the basal (BAO) and peak (PAO) acid output and fasting plasma gastrin concentration were measured 24 h after the seventh dose. Omeprazole suppressed PAO significantly and dose-dependently after doses of 10, 20 and 40 mg, the suppression being 42%, 75% and 85%, respectively. No patient showed complete inhibition of PAO and at least 20 mg had to be given to obtain a marked inhibitory effect in all patients. Increasing the dose to 40 mg had only a slight additional effect compared to 20 mg. There was a relationship between degree of acid inhibition and the increase in fasting plasma gastrin. PAO had to be suppressed by more than 80% before a moderate increase in fasting plasma gastrin was observed. The optimal once-daily oral dose of omeprazole for inhibition of acid secretion in elderly patients appears to be 20 mg. Omeprazole 20-40 mg may cause a moderate increase in fasting plasma gastrin.

Dose-related healing of duodenal ulcer with the proton pump inhibitor lansoprazole

Lansoprazole (AG 1749) is a novel substituted benzimidazole which inhibits gastric acid secretion by blocking H+,K(+)-ATPase. This randomized, double-blind multicentre trial studied the dose-response relationship of lansoprazole on ulcer healing and compared it with ranitidine in 314 out-patients with endoscopically assessed, symptomatic duodenal ulcer. Cumulative healing rates with Lansoprazole 7.5, 15, and 30 mg o.m. were 48, 59, and 74% at 2 weeks and 75, 84, and 95% at 4 weeks, respectively (intention-to-treat); the difference of the healing rates between 7.5 and 30 mg groups was significant (P less than 0.001). Corresponding healing rates for 300 mg ranitidine nocte were 51 and 89%. Pain relief was similar in all treatment groups. Lansoprazole was well tolerated. During a follow-up of 6 months relapse rates after lansoprazole 7.5, 15, and 30 mg were 21, 29, and 22%, respectively; the relapse rate after ranitidine 300 mg was 20%. In conclusion, lansoprazole provides faster healing of duodenal ulcer than ranitidine and a similar relapse pattern. For further trials in peptic ulcer disease a daily dose of lansoprazole 30 mg o.m. is recommended.

Ranitidine in the treatment of duodenal ulcer disease: relationship between antisecretory effect and ulcer healing rate

The relationship between drug-induced suppression of intragastric acidity and the rate of duodenal ulcer healing was examined using data for a single drug, ranitidine, from 156 clinical trials involving 16,362 patients together with data on acid suppression from 37 studies of intragastric acidity in 630 subjects. In these studies ranitidine was given in doses ranging from 150 mg to 1200 mg per day administered in 9 different dosage regimens. The overall percentage of patients whose duodenal ulcers healed at 2 and 4 weeks on the different regimens was highly correlated with the percentage suppression of 24-hour intragastric acidity induced by different regimens. Thus the therapeutic benefit of a given ranitidine dosage regimen in healing duodenal ulcers relates directly to its antisecretory effect.

24-hour intragastric acidity and plasma gastrin during long-term treatment with omeprazole or ranitidine in patients with reflux esophagitis

The reduction in intragastric acidity and the subsequent increase in plasma gastrin were compared during long-term treatment with either omeprazole or ranitidine in 19 patients with erosive reflux esophagitis. The patients received 40 mg omeprazole in the morning or 300 mg ranitidine twice daily. After healing, half the dose was given as maintenance treatment for 1 year. Intragastric acidity and plasma gastrin were measured 24 h before entry and monthly with the high dose and after 1, 6, and 12 months with the low dose. Omeprazole reduced intragastric acidity more effectively than ranitidine (p less than 0.001). This difference in efficacy was more pronounced during the daytime. Plasma gastrin increased more after omeprazole than after ranitidine (p less than 0.01), and both drugs showed a normal postprandial response and approached fasting levels before the next dose. During long-term treatment with 20 mg omeprazole in the morning no progressive alterations were observed in 24-h intragastric acidity or plasma gastrin.

Nocturnal intragastric acidity during and after a period of dosing with either ranitidine or omeprazole

The magnitude and duration of changes in nocturnal intragastric acidity caused by 25 days of dosing with the antisecretory drugs ranitidine and omeprazole were investigated in a double-blind study of 22 healthy subjects. Nocturnal intragastric acidity was studied before (twice), during (on day 25), and after (every 3 days for 21 days) dosing with either 300 mg ranitidine at night or 40 mg omeprazole every morning. Three and six days after withdrawal of dosing with ranitidine, median integrated nocturnal intragastric acidity was increased significantly (17% and 14%, P = 0.01 and P = 0.05, respectively) compared with before dosing. Three days after withdrawal of dosing with omeprazole, median integrated nocturnal intragastric acidity was decreased significantly (-23%, P = 0.003). Compared with before dosing, no significant differences were seen in the ranitidine group between days 9 and 21 or the omeprazole group between days 6 and 21 after cessation of dosing. Fasting plasma gastrin concentration was measured on the morning of each study; compared with before treatment, the only significant elevations occurred on the last day of dosing with omeprazole (before, 4 pmol/L; during, 7 pmol/L). It is concluded that rebound intragastric hyperacidity after dosing with 300 mg ranitidine at night or sustained hypoacidity after dosing with 40 mg omeprazole every morning reflect transient disturbances of gastric function that are unlikely to be of clinical importance.

Omeprazole. Overview and opinion

Omeprazole, a substituted benzimidazole, is a specific inhibitor of the enzyme H+/K(+)-ATPase, which is found on the secretory surface of the parietal cell. This enzyme, the "proton pump," catalyzes the final step in acid secretion. Omeprazole is a powerful inhibitor of gastric acid secretion. At the time of writing, omeprazole has been licensed in the United States for the treatment of severe grades of gastroesophageal reflux disease (GERD) as well as GERD unresponsive to treatment with currently available agents, and for the treatment of Zollinger-Ellison syndrome and other gastric hypersecretory states. Most recently, it has been recommended by the FDA advisory committee for approval as first-line therapy in duodenal ulcer disease.

Peptic ulcer disease. How to treat it now

Options for treatment of peptic ulcer disease are becoming more diverse. Most new agents are effective yet offer no real advantage over more traditional therapy. However, omeprazole (Prilosec) may be of benefit owing to its potent inhibition of acid secretion, but it is not yet approved for this purpose. Whether treatment of Helicobacter pylori infection will prove beneficial is not yet known, but the answer should be forthcoming. Finally, as with any disease process, alleviation of risk factors is always important. Appropriate counseling regarding use of nonsteroidal anti-inflammatory drugs and cigarette smoking is a necessity.

Influence of acid secretory status on absorption of omeprazole from enteric coated granules

1. In order to study the absorption of omeprazole under normal acidic conditions in the stomach as well as when the granules are exposed to minimal gastric acid, eight healthy males were given 20 mg omeprazole as enteric coated (EC) granules either alone or 2 h after a ranitidine dose of 300 mg, respectively. 2. Blood samples were collected at intervals for 12 h following both omeprazole administrations. The pH was recorded during the first 4 h in half the subjects in each experiment to document the difference in pH during the absorption phase of omeprazole. 3. The area under the plasma concentration-time curve, AUC, of omeprazole was virtually the same irrespective of whether or not the granules were exposed to gastric acid. However, the maximum plasma concentration (Cmax) was higher and the time to reach Cmax was shorter when omeprazole was administered after a ranitidine dose. 4. It is concluded that gastric acidity has negligible influence on the AUC of omeprazole, which is directly correlated to the antisecretory effect, when administered as EC granules.

Two and four weeks' treatment for duodenal ulcer. Symptom relief and clinical remission comparing omeprazole and ranitidine. Scandinavian Clinics for United Research

In a Swedish-Norwegian multicentre study patients with endoscopically verified duodenal ulcers (greater than 5 mm) were randomized to 2 or 4 weeks of treatment with either 20 mg omeprazole once daily or 300 mg ranitidine once daily. The aim was to evaluate 2 and 4 weeks' treatment with regard to symptomatic improvement during treatment, relapse after treatment, and safety of the two drugs. Endoscopy was not performed to check healing at the end of treatment. Instead the patients were instructed to contact the investigator in the event of recurrence of symptoms for renewed endoscopy. Follow-up was ended 10 weeks after stopping active treatment. Altogether 450 patients were evaluated at 17 centres. The symptomatic improvement during treatment was good in all groups, with significantly better reductions of daytime pain and heartburn in omeprazole-treated patients. Symptomatic relapse was commonest in the 2-week ranitidine group (57%), significantly more than in the 2-week omeprazole group (31%) (p less than 0.003). In the 4-week groups relapse rates were 34% (ranitidine) and 39% (omeprazole) (NS). It is suggested that in the short-term treatment of acute duodenal ulcer 20 mg omeprazole once daily is most rationally used in a 2- to 4-week regimen, whereas 300 mg ranitidine once daily should not be used for less than 4 weeks.

Clinical pharmacology of omeprazole

Omeprazole is a specific inhibitor of H+,K(+)-ATPase or 'proton pump' in parietal cells. This enzyme is responsible for the final step in the process of acid secretion; omeprazole blocks acid secretion in response to all stimuli. Single doses produce dose-dependent inhibition with increasing effect over the first few days, reaching a maximum after about 5 days. Doses of omeprazole 20mg daily or greater are able to virtually abolish intragastric acidity in most individuals, although lower doses have a much more variable effect. Omeprazole causes a dose-dependent increase in gastrin levels. Omeprazole must be protected from intragastric acid when given orally, and is therefore administered as encapsulated enteric-coated granules. Absorption can be erratic but is generally rapid, and initially the drug is widely distributed. It is highly protein-bound and extensively metabolised. Its elimination half-life is about 1h but its pharmacological effect lasts much longer, since it is preferentially concentrated in parietal cells where it forms a covalent linkage with H+,K(+)-ATPase, which it irreversibly inhibits. Omeprazole binds to hepatic cytochrome P450 and inhibits oxidative metabolism of some drugs, the most important being phenytoin. Omeprazole has produced short term healing rates superior to the histamine H2-receptor antagonists in duodenal ulcer, gastric ulcer and reflux oesophagitis. It has also been shown to be highly effective in healing ulcers which have failed to respond to H2-receptor antagonists, and has been extremely valuable in treating patients with Zollinger-Ellison syndrome.

Lack of effect of omeprazole treatment on steady-state plasma levels of metoprolol

In a randomised double-blind crossover study, seven healthy males were concomitantly given metoprolol 100 mg o.d. as a controlled release formulation, and omeprazole 40 mg o.d. or placebo, for 8 days. Plasma levels of the R- and S-enantiomers of metoprolol were determined on the 8th day of each treatment. The subjects were also characterised by their metabolic capacity to hydroxylate debrisoquine. Concomitant omeprazole treatment had no significant influence on the steady-state plasma levels of the two enantiomers of metoprolol. All subjects were characterised by extensive debrisoquine hydroxylation, i.e. extensive metoprolol metabolism. As metoprolol is metabolised to a great extent by debrisoquine hydroxylase (IID6), it is concluded that concomitant omeprazole treatment will probably have a negligible influence on the metabolism of the relatively large number of drugs mainly metabolised by this isoenzyme of the cytochrome P450 family.

Double blind comparative study of omeprazole and ranitidine in patients with duodenal or gastric ulcer: a multicentre trial. Cooperative study group

We studied omeprazole and ranitidine in promoting duodenal ulcer healing in a multicentre trial by comparing the proportion of healed ulcers after two, four, and eight weeks of treatment. Altogether, 194 patients (143 men) were randomly allocated according to a prearranged treatment schedule to either drug and were treated double blind. Each received 40 mg omeprazole in the morning and a ranitidine placebo morning and evening or 150 mg ranitidine morning and evening with an omeprazole placebo in the morning. A total of 188 patients (94 taking omeprazole, 94 taking ranitidine) completed the trial. Sixty four (68%) omeprazole treated and 45 (48%) ranitidine treated patients had healed ulcers at two weeks, 91 (99%) omeprazole treated and 79 (88%) ranitidine treated had healed ulcers by four weeks, and 91 (100%) omeprazole treated and 86 (97%) ranitidine treated patients had healed ulcers by eight weeks. The overall difference in healing rates was significant (p = 0.0008, Mantel-Haenszel test). The differences were significant also at two weeks (20%, 95% confidence interval 5.6 to 34.4, p less than 0.01) and at four weeks (11%, 95% CI 3.7 to 17.3, p less than 0.01), but not at eight weeks (3%, 95% CI -0.5 to + 7.3, p = 0.25), using the chi 2 statistic, the study having a power to detect a 20% difference on 90% of occasions. After two weeks of treatment complete symptom relief was observed in 70 (74%) patients receiving omeprazole and in 58 (62%) receiving ranitidine. Diary cards showed a significantly lower percentage of days with pain in the omeprazole treated group (7.4% v 21.4%, p < 0.02) when assessed over either the first two weeks or over weeks three and four treatment. A total of 144 patients with healed duodenal ulcer were followed up, with no treatment, for six months. At the end of this period 19 (26%) of 74 patients healed with omeprazole and 17 (24%) of 70 patients healed with ranitidine were still in remission. A similar protocol was used for 46 patients (25 men) with gastric ulcer who were randomly allocated to treatment with omeprazole or ranitidine as described above. Forty patients (16 omeprazole, 24 ranitidine) completed trial. Thirteen (81%) omeprazole treated and 14 (58%) ranitidine treated patients had healed ulcers at four weeks; at eight weeks 14 (93%) omeprazole treated and 20 (87%) ranitidine treated patients had healed ulcers. These differences were not significant at four weeks (p = 0.25) or eight weeks (p = 0.96). Twenty seven gastric ulcer patients were followed up for six months and seven (58%) of the 12 omeprazole healed and five (33%) of the 15 ranitidine healed patients were in remission at six months. Unwanted adverse events were trivial except for one fatality in a 67 year old women, who died from bronchopneumonia and myocardial ischaemia while receiving treatment with omeprazole, which was judged to be unrelated to her death.

Pharmacokinetics and bioavailability of omeprazole after single and repeated oral administration in healthy subjects

1. Ten healthy subjects were given 20 mg omeprazole EC (enteric coated) granules once daily for 8 days. An i.v. tracer dose of [14C]-omeprazole was given simultaneously with the first and last oral doses and blood sampling was performed thereafter. In order to study the extent of absorption at minimal acid exposure, a single dose of 20 mg omeprazole was also given as a buffered solution, before and after the treatment with EC granules. 2. Kinetic parameters of omeprazole after the i.v. tracer dose were unchanged on repeated dosing while AUC increased by approximately 40% for the solution and 60% for the EC granules. 3. The increased AUC is caused by an increased systemic availability, which may be explained by a decreased first-pass elimination during repeated treatment and/or by a reduced degradation of omeprazole in the stomach secondary to the profound decrease in intragastric acidity caused by the drug. 4. The implication of these findings is that the antisecretory effect of therapeutic doses of omeprazole must be studied during repeated administration and not judged from studies using single doses only.

Omeprazole: a novel antisecretory agent for the treatment of acid-peptic disorders

Omeprazole represents the first agent of a unique class of acid inhibitory drugs, the proton pump inhibitors. Omeprazole inhibits basal gastric acid secretion, as well as gastrin-, histamine-, or pentagastrin-stimulated secretion, which results in decreased gastric acidity, decreased gastric acid output, and decreased gastric volume. Omeprazole is acid labile, necessitating its oral administration in an enteric-coated formulation. Bioavailability appears to be dose-dependent, with more drug being absorbed with increasing dosage as well as after repeated dosing. This is probably secondary to decreased gastric acidity and, therefore, less degradation of the administered drug. Despite its relatively short half-life (1-2 h), omeprazole's pharmacologic action is prolonged. Clinical trials have shown omeprazole to be at least as effective as histamine2-receptor antagonists in the treatment of gastric ulcers, duodenal ulcers, gastroesophageal reflux, and Zollinger-Ellison syndrome. Adverse reactions have been minimal. Omeprazole has been approved by the Food and Drug Administration for short-term therapy of severe erosive esophagitis, poorly responsive symptomatic gastroesophageal reflux disease, and long-term management of Zollinger-Ellison syndrome.

Omeprazole provides quicker symptom relief and duodenal ulcer healing than ranitidine

In a double-blind, parallel-group clinical trial in 248 patients with symptomatic duodenal ulcers [97% greater than 5 mm diameter], 126 were randomized to receive omeprazole 20 mg once daily in the morning and 122 were randomized to receive ranitidine 300 mg once daily at night for 2 wk and if the ulcers were unhealed for a total of 4 wk. When ulcer healing was assessed on an intention-to-treat basis, 79% of those receiving omeprazole had healed ulcers after 2 wk compared with 62% of those receiving ranitidine (p less than 0.005; therapeutic gain for omeprazole, 18%; 95% confidence intervals, +6% to +29%). At 4 wk the figures were 91% (omeprazole) and 80% (ranitidine) (p less than 0.05). After 2 wk, 77% of omeprazole-treated and 59% of ranitidine-treated patients were free of ulcer pain (p = 0.005). Assessed by diary cards (successfully completed by 92% of patients), daytime pain resolved more quickly in omeprazole-treated patients than in those receiving ranitidine (p less than 0.01). Omeprazole-treated patients took fewer antacids (p less than 0.05) over the first 2 wk. Omeprazole, 20 mg each morning, provides more rapid relief of the symptoms of duodenal ulcer and heals a greater proportion of duodenal ulcers within 2 and 4 wk than ranitidine, 300 mg each night.

Omeprazole versus placebo in duodenal ulcer healing. The United States experience

The study objective was to study the ulcer healing effects and safety of the proton pump inhibitor, omeprazole, given in a dose of 20 mg once daily before breakfast. The study design was a randomized, double-blind, multicenter comparison of omeprazole and placebo using endoscopy to assess ulcer healing after two or four weeks of therapy. One hundred fifty-three patients with endoscopically documented active duodenal ulcer were studied. One hundred two patients received omeprazole and 51 received placebo. Patients in both groups were similar with regard to age, sex, duration of disease, initial ulcer size, smoking history, and alcohol use. A "per protocol" analysis of healing rates showed a significant advantage for omeprazole (P less than 0.01) at both week 2 (41% vs 13%) and week 4 (75% vs 27%). Concomitant factors (including smoking and ulcer size) did not alter the significance of the differences in healing rates between omeprazole and placebo. Complete relief of day and night pain was more often achieved (P less than 0.01) in the omeprazole group. "All-patients treated" analyses for healing and pain relief gave results similar to the respective "per protocol" analyses. Omeprazole was well tolerated; fewer patients had clinical and laboratory adverse experiences in the omeprazole group than in the placebo group. Fasting serum gastrin levels increased with omeprazole therapy (mean 34.9 to 73.5 pg/ml) but exceeded the normal range (greater than 150 pg/ml) in only 12.3% of patients. Two weeks after therapy was stopped, serum gastrin levels showed a decrease toward baseline but had not yet completely returned to pretreatment levels (mean 49.7 pg/ml).(ABSTRACT TRUNCATED AT 250 WORDS)

Omeprazole and ranitidine in duodenal ulcer healing. Analysis of comparative clinical trials

Ten double-blind randomized studies with omeprazole versus ranitidine in duodenal ulcer healing have been published. The total number of patients in the trials amounted to 2225. To detect treatment differences, a meta-analysis was performed. After 2 and 4 weeks of treatment results have been evaluated. After 2 weeks of treatment omeprazole produced higher healing rates than ranitidine in nine studies. However, at 4 weeks numerical differences in favour of omeprazole were found in nine studies. Relief of ulcer symptoms occurred more rapidly with omeprazole than ranitidine. No major clinical or biochemical side effects were recorded. However, no data are available about maintenance therapy in double-blind randomized studies comparing both drugs or about rebleeding rates in bleeding duodenal ulcer treatment.

Duodenal ulcer treated with omeprazole: healing and relapse rates. Does treatment duration influence subsequent remission?

One hundred and twenty-nine patients were studied with regard to healing of duodenal ulcers with 30 mg omeprazole once daily, recurrence rates after 2 and 4 weeks' treatment in patients with ulcers healed after 2 weeks, and recurrences in rapid and slow healers. Cumulative healing rates were 77% and 98% after 2 and 4 weeks, respectively. Eighty-one patients (65%) were without ulcer symptoms after 2 weeks, and 43 (34%) were improved. Seven of 45 patients (16%; 95% confidence limits, 6-30%) with ulcers healed after 2 weeks had relapsed after another 2 weeks of placebo; 3 were asymptomatic. The overall relapse rate after 6 months was 62%. There were no statistically significant differences in relapse rates between 2 and 4 weeks' treatment of patients with ulcers healed after 2 weeks or between rapid and slow healers. Ulcer size, smoking habits, and alcohol consumption were not significantly related to healing or relapse.

Omeprazole (20 mg o.m.) versus ranitidine (150 mg b.d.) in duodenal ulcer healing and pain relief

The object of this double-blind, multicentre study was to compare duodenal ulcer healing rates after 2 to 4 weeks of treatment with either 20 mg omeprazole o.m. or 150 mg ranitidine b.d. One hundred and eighty-one patients were randomized: 91 received omeprazole and 90 received ranitidine. In a per protocol analysis at 2 weeks, 63% of the patients were healed on omeprazole and 65% of the patients were healed on ranitidine (N.S.); at 4 weeks 91% were healed in the omeprazole group and 96% were healed in the ranitidine group. There were no differences in ulcer symptom relief between the two groups. There were no significant changes in laboratory values in either of the groups. Adverse events were few and mainly mild and transient. We conclude that both omeprazole (20 mg o.m.) and ranitidine (150 mg b.d.) result in rapid, ulcer healing rates.

The pharmacology of antiulcer drugs

The use of medications for the treatment of gastrointestinal ulcers has evolved to a great extent since the early days of therapy with diet and antacids. Today a number of different agents are available to treat the causative factors of ulcer formation. Currently, antacids, histamine2-receptor antagonists, and sucralfate are considered frontline therapies suitable for most patients. The future also looks promising for newer agents, such as omeprazole and prostaglandin analogs. The purpose of this article is to provide practitioners with an understanding of the achieved more efficiently and effectively.

Therapeutic achlorhydria and risk of gastric cancer

New, powerful gastric secretory inhibitors, such as omeprazole, produce gastric cancer in rats. The mechanism by which the drugs elicit gastric carcinogenesis is considered to depend on the production of therapeutic achlorhydria, with subsequent release in to the circulation of peptides (such as gastrin) which are trophic to the gastric mucosa. It has been argued that the drugs do not pose a carcinogenic risk to man because the neoplastic response to gastric inhibitors in rats is a reaction to a 'toxic' insult; or because rats and humans react differently to the drugs; or because the mechanisms of gastric carcinogenesis are different in the two species. In any case, since most of the powerful gastric secretory inhibitors produce carcinoid tumours in rats, and carcinoid tumours of the human stomach are rare and largely benign, there would be no risk even if the drugs did produce proliferative abnormalities of the human stomach. Not one of the above hypotheses has been confirmed or, indeed, even satisfactorily tested. The mechanisms of the drug-induced gastric carcinogenesis in rats has not been defined and consequently it is not even possible to attempt to guess the risk to man. Until information is available about the effects of the powerful gastric secretory inhibitors on the proliferative indices and patterns of the human gastric mucosa, the drugs must be categorized as too dangerous to use therapeutically, especially since the proposed therapeutic benefits are minimal.

Long-term efficacy and safety of omeprazole in patients with Zollinger-Ellison syndrome: a prospective study

To determine the long-term efficacy, safety, and toxicity of omeprazole, we studied 40 patients with Zollinger-Ellison syndrome given omeprazole for 6-51 mo (median 29). The mean daily dose of omeprazole required to control gastric acid secretion was 82 +/- 31 mg. Thirty-one patients required omeprazole once per day. In 9 patients acid output was not controlled by 120 mg once per day, but was controlled by 60 mg every 12 h. The daily dose of omeprazole correlated with the previous dose of histamine H2-receptor antagonist (r = 0.89, p less than 0.001), basal acid output (r = 0.43, p less than 0.01), and maximal acid output (r = 0.39, p less than 0.02) but not with serum concentration of gastrin (r = -0.32). Increases in the dose of omeprazole were required in 9 patients. Twenty-nine patients had mild peptic symptoms with acid outputs less than 10 mEq/h while taking histamine H2-receptor antagonists. Symptoms resolved completely in 23 patients and partially in 3 when taking omeprazole. Omeprazole prevented mucosal disease in all patients including 17 in whom histamine H2-receptor antagonists had produced only partial resolution despite acid output being less than 10 mEq/h and in those with symptoms during omeprazole therapy. Omeprazole therapy was not associated with any significant side effects, nor with any evidence of hematologic or biochemical toxicity. Serum concentrations of gastrin did not change significantly during therapy. In 6 patients treated with omeprazole for 1 yr there was no change in basal or maximal acid output. In all patients, gastric morphology and histopathology demonstrated no evidence of gastric carcinoid formation. These results demonstrate that with long-term treatment of up to 4 yr, omeprazole is safe, with no evidence of hematologic, biochemical, or gastric toxicity. Furthermore, omeprazole remained effective, with only 23% of patients requiring an increase in dose, and continued to control symptoms in patients who had not been entirely symptom-free despite high doses of histamine H2-receptor antagonists. Omeprazole is now the drug of choice in patients with Zollinger-Ellison syndrome.

Double blind multicentre comparison of omeprazole 20 mg once daily versus ranitidine 150 mg twice daily in the treatment of cimetidine or ranitidine resistant duodenal ulcers

The purpose of the present study was to compare omeprazole 20 mg once daily and ranitidine 150 mg twice daily in healing duodenal ulcers unhealed by previous treatment with cimetidine greater than or equal to 0.8 g or ranitidine greater than or equal to 0.3 g daily for at least six weeks. In a double blind multicentre trial, 151 patients were randomly assigned to either omeprazole or ranitidine. Clinical assessments and endoscopies were carried out at two and four weeks. Patients characteristics were similar in both groups. Statistical analysis (chi 2 test) did not show any significant difference in healing rate (p greater than 0.20) irrespective of the method of calculation. On an 'intent-to-treat' analysis (n = 151), healing was: omeprazole 46.6%, ranitidine 43.3% at day 15 and omeprazole 70.7%, ranitidine 68.4% at day 29; and among the patients who completed treatment, healing was: omeprazole 48.3%, ranitidine 46.3% at day 15 (n = 125; 95% confidence interval of the difference--17 to 21) and omeprazole 79.6%, ranitidine 75.4% at day 29 (n = 115; 95% confidence interval of the difference--13 to 21). After a further four weeks treatment with omeprazole, healing occurred in 16/20 (80%) who still had active disease at day 29. Patients on omeprazole and on ranitidine experienced similar decrease in day time and night time epigastric pain and in heartburn. Multivariate analysis (logistic regression) did not indicate any influence on age, sex, smoking and alcohol habits, previous drug administered, duodenitis and duodenal erosions on the healing rate. In this model, healing rate was not significantly influenced by previous treatment duration (p = 0.09 at day 15 and p greater than 0.2 at day 29) but was significantly influenced by ulcer size (p = 0.04 at day 15 and p = 0.02 at day 29). Forty one patients complained of adverse events: 19 on omeprazole (four trial withdrawals), 22 on ranitidine (three trial withdrawals).

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.

Twenty-four-hour intragastric acidity in duodenal ulcer patients during dosing with placebo, and 150 mg ranitidine twice or four times daily

Twenty-four-hour intragastric acidity was measured in 10 patients with a past history of duodenal ulcer on the fourth day of dosing with placebo, and either 150 mg ranitidine given twice or four times daily. The order of the treatments was randomized and a double-blind design was employed. Ranitidine (150 mg) b.d. decreased median integrated 24-h intragastric acidity by 65.1%, nocturnal acidity by 89.1%, and daytime acidity by 54.6% (all P less than 0.01 compared to placebo). The corresponding decreases with 150 mg ranitidine q.d.s. were 62.3, 89.9 and 48.8%, respectively (all P less than 0.01) compared to placebo). There were no significant differences between the two dosage regimens of ranitidine (P greater than 0.05). This study shows that giving extra doses of 150 mg ranitidine during the day does not increase the degree of suppression of intragastric acidity.

Ranitidine. An updated review of its pharmacodynamic and pharmacokinetic properties and therapeutic use in peptic ulcer disease and other allied diseases

Ranitidine, a histamine H2-receptor antagonist, is now well established as a potent inhibitor of gastric acid secretion effective in the treatment and prophylaxis of gastrointestinal lesions aggravated by gastric acid secretion. Therapeutic trials involving several thousands of patients with peptic ulcer disease confirm that ranitidine 300mg daily administered orally in single or divided doses is at least as effective as cimetidine 800 to 1000mg daily in increasing the rate of healing of duodenal and gastric ulcers. Similar dosages of ranitidine have been shown to relieve the symptoms of reflux oesophagitis and heal or prevent gastrointestinal damage caused by ulcerogenic drugs. Ranitidine 150mg orally at night maintains ulcer healing in the long term. Ranitidine has also demonstrated good results in the treatment of Zollinger-Ellison syndrome and in the prevention of aspiration pneumonitis when given prior to surgery and to pregnant women at full term. It may also have a place in the management of acute upper gastrointestinal bleeding and in the prevention of stress ulcers in the intensive care setting, although these areas require further investigation. Ranitidine has been used safely in obstetric patients during labour, in children, the elderly, and in patients with renal impairment when given in appropriate dosages. The drug is very well tolerated and is only infrequently associated with serious adverse reactions or clinically significant drug interactions. Even at high dosages, ranitidine appears devoid of antiandrogenic effects. Ranitidine is clearly comparable or superior to most other antiulcer agents in the treatment and prevention of a variety of gastrointestinal disorders associated with gastric acid secretion. With its favourable efficacy and tolerability profiles, ranitidine must be considered a first-line agent when suppression of gastric acid secretion is indicated.

Effect of 10 mg and 20 mg omeprazole daily on duodenal ulcer: double-blind comparative trial

One-hundred and seventy-one patients with endoscopically proven duodenal ulcers were allocated at random to double-blind treatment with 10 or 20 mg of omeprazole in the morning for up to 4 weeks. Patients completed the study if ulcer healing and pain relief had occurred at 2 weeks. A total of 155 patients completed the trial. Patients treated with 20 mg of omeprazole daily responded significantly more rapidly than those treated with 10 mg of omeprazole daily (P less than 0.001; Cochran-Mantel-Haenszel test covering both time points), cumulative healing rates at 2 and 4 weeks were 74% (58/78) and 91% (71/78), respectively. The corresponding rates in the group treated with 10 mg daily were 48% (39/81) and 75% (58/77). Pain relief was again more pronounced during treatment with the larger dose (P less than 0.05; stratified Wilcoxon test). No major clinical or biochemical side effects were noted. An omeprazole dose of 20 mg daily is preferable to a lower dose for the treatment of duodenal ulcer disease in the short term.

Symptom relief and duodenal ulcer healing with omeprazole or cimetidine. Opus (Omeprazole Peptic Ulcer Study) Research Group

In a double-blind parallel-group study, 98 patients with symptomatic duodenal ulcer received omeprazole 20 mg o.m. and 91 cimetidine 800 mg nocte for 2 or, if then not healed, 4 weeks. After 2 weeks the healing rates on an intention-to-treat basis were: for omeprazole 62% and for cimetidine 33% (P less than 0.001), and at 4 weeks 85% and 61%, respectively (P less than 0.001). The proportions symptom-free at 2 weeks were 83% of the omeprazole and 63% of the cimetidine-group (P less than 0.01) and at 4 weeks 84% and 72% (P = 0.01). Patients receiving omeprazole took fewer antacid tablets than those receiving cimetidine. Patient tolerance of both drugs was similar and good. In the treatment of duodenal ulcer, omeprazole 20 mg o.m. gives faster symptom relief than cimetidine 800 mg nocte, as well as healing a greater proportion of ulcers within 2 and 4 weeks.

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

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

Omeprazole in the treatment of duodenal ulcer

Omeprazole is the most effective antisecretory agent available today. Open and dose-comparative studies have documented that at dosages of 20 mg/day or more, the drug produces duodenal ulcer healing rates of 90-100% after 4 weeks. Controlled trials show that omeprazole, 20-40 mg/day, is superior to cimetidine and ranitidine in healing duodenal ulcer, with a median therapeutic gain of 21% at 2 weeks and 15% at 4 weeks. Ulcer symptom relief is also more pronounced and faster with omeprazole than with H2-receptor antagonists. No significant side-effects attributable to treatment with omeprazole have appeared in any of these studies or in the accumulated experience from several thousand patients treated with omeprazole. No tendency to an increase in recurrence rate after discontinuation of treatment with omeprazole has been shown. In summary, omeprazole constitutes a major advance in the short-term treatment of duodenal ulcer, giving fast and pronounced healing and symptom relief.

Use of omeprazole in the management of reflux oesophagitis resistant to H2-receptor antagonists

Severe reflux oesophagitis, which is resistant to treatment with high doses of H2-receptor antagonists, can be treated successfully with the H+,K+-ATPase inhibitor omeprazole. Experience from more than 3 years of continuous treatment with omeprazole, in doses adjusted to prevent recurrences, has demonstrated its high efficacy in the long-term management of the patients. The use of this drug emphasizes the importance of long-standing, effective, 24-hour acid inhibition for reflux oesophagitis. Fasting gastrin levels increase 2-fold during the initial treatment period but continued treatment does not induce any further elevation. Omeprazole does not induce pathological changes in the endocrine cell population of the gastric oxyntic mucosa, though in some patients an increase in the argyrophilic cell volume density during omeprazole treatment has been reported. Careful surveillance of the safety profile of this drug is continuing.

The clinical utility and safety of omeprazole

More than 13,000 individuals with duodenal ulcer, gastric ulcer or reflux oesophagitis have now taken part in controlled clinical studies with omeprazole. In duodenal ulcer, treatment with omeprazole, 20 mg daily or more, has resulted in healing rates of 58%-83% after 2 weeks and 84%-100% after 4 weeks. In all of these studies, healing rates with omeprazole have been higher than with either ranitidine or cimetidine. Omeprazole has also had a more pronounced effect on ulcer symptoms. Although the first comparative study on gastric ulcer showed only marginally higher healing rates with omeprazole than with an H2-receptor antagonist, later studies have all shown significantly higher healing rates with omeprazole. Healing rates of the order of 70% or more have been achieved within 4 weeks, rising to over 88% after 8 weeks. Symptom relief has also been faster with omeprazole. In both duodenal ulcer and gastric ulcer, almost every patient can be healed, including those resistant to treatment with H2-receptor antagonists. The influence of omeprazole on the healing of reflux oesophagitis has been investigated in several studies comparing omeprazole with ranitidine. Healing rates have been markedly higher with omeprazole in all studies. These unprecedentedly high healing rates (81%-96% at 8 weeks) have also been accompanied by rapid symptom relief. In clinical studies with omeprazole, no clinically significant side-effects which could be ascribed to treatment, nor indeed any serious side-effects, have been observed, neither have any clinically significant changes in laboratory variables been seen. Furthermore, no pathological changes of the gastric mucosa have been detected after long-term treatment with omeprazole.

Prospective double-blind trial of duodenal ulcer relapse after eradication of Campylobacter pylori

100 consecutive patients with both duodenal ulcer and Campylobacter pylori infection were followed up to see whether eradication of C pylori affected ulcer healing or relapse. Patients were randomly assigned to 8 weeks of treatment with cimetidine or colloidal bismuth subcitrate (CBS), with tinidazole or placebo being given concurrently from days 1 to 10, inclusive. Endoscopy, biopsy, and culture were done at entry, in weeks 10, 22, 34, and 62, and whenever symptoms recurred. There was no maintenance therapy. C pylori persisted in all of the cimetidine-treated patients and in 95% of those treated with cimetidine/tinidazole, but was eradicated in 27% of the CBS/placebo group and 70% of the CBS/tinidazole group. When C pylori persisted, 61% of duodenal ulcers healed and 84% relapsed. When C pylori was cleared 92% of ulcers healed (p less than 0.001) and only 21% relapsed during the 12 month follow-up period (p less than 0.0001).

Effect of 'weekend therapy' with omeprazole on basal and stimulated acid secretion and fasting plasma gastrin in duodenal ulcer patients

The effect of intermittent dosage with omeprazole on basal and pentagastrin stimulated gastric acid secretion and fasting plasma gastrin was assessed in eight duodenal ulcer subjects who were in remission. Omeprazole (20 mg daily) was given for a three day 'weekend' each week for two months. Twenty four hours after the first and eighth weekend, basal and peak acid output were still markedly suppressed (greater than 50%) compared with pretreatment. After the treatment free four days, however (just before the eighth weekend), peak acid output had returned to pretreatment values; basal acid output was still somewhat reduced (mean 3.6 mmol/l) but the difference from baseline was not statistically significant. Fasting plasma gastrin concentration increased slightly but significantly, from a baseline median of 17 pmol/l to 25 and 31 pmol/l respectively, 24 hours after the first and eighth weekends. All but two values (of 16) remained within the reference range. Before the fourth and eighth weekends, and again at 12 days and three months after treatment, gastrin values were not significantly different from baseline. Thus a 'weekend therapy' regimen with this long acting antisecretory compound produces substantial acid suppression, but for only part of the week, with modest and reversible changes in fasting plasma gastrin. It should therefore be suitable for efficacy testing for prevention of recurrence of peptic ulcer or reflux oesophagitis.

The timing of evening meal and ranitidine administration--effects on patterns of 24 hour intragastric acidity

Intragastric pH-metry was utilized to assess the effect of the time of meal ingestion and ranitidine administration on 24-h intragastric acidity. Twelve volunteers with a documented history of duodenal ulcer were studied in a four-way crossover design. Subjects randomly received ranitidine at 18.00 and 22.00 hours, with and without food. Serial blood samples were collected and analysed for ranitidine by high pressure liquid chromatography. Over the interval of 18.00-0.700 hours, the mean hydrogen-ion activity was significantly lower with the 18.00 hour dose than with the 22.00 hour dose (P less than or equal to 0.05). There were no differences between the four treatments in median pH or mean hydrogen-ion activity over the 23-h study interval. There were no differences between treatments in peak ranitidine concentrations, time to peak concentration, area under the serum-concentration time curve or elimination half-life.

Relationship between reduction of gastric acid secretion and plasma gastrin concentration during omeprazole treatment

We have studied the relationship between reduction of gastric acid secretion and fasting plasma gastrin concentrations during once daily omeprazole treatment. Healthy subjects were given omeprazole for 5 days in daily doses of 5, 10, 20, 40, or 80 mg. Acid secretion and fasting gastrin concentration were measured 6 h (maximal omeprazole effect) and 24 h (minimal omeprazole effect) after the fifth omeprazole dose. Omeprazole in doses lower than 20 mg daily did not suppress pentagastrin-stimulated acid secretion in all subjects 6 h after dosing on the 5th day. Doses of 20-80 mg omeprazole, however, significantly reduced acid secretion 24 h after the fifth dose, the range being 36-76%. A relationship between degree of acid inhibition and fasting gastrin concentration was observed. However, acid secretion needed to be reduced by more than 80% before gastrin levels were clearly affected. This degree of acid inhibition was only achieved 6 h after administration of omeprazole in doses of 20 mg and higher. The inhibitory effect of omeprazole on acid secretion decreased 24 h after dosing. Thus, fasting gastrin concentrations were moderately increased in the beginning and normalized at the end of each 24-h period during treatment with daily doses of 20-80 mg omeprazole.