Omeprazole: a pharmacoeconomic evaluation of its use in duodenal ulcer and reflux oesophagitis

Omeprazole regulates gastric acid secretion and is an effective treatment of acute duodenal ulcer and reflux oesophagitis, achieving more rapid healing and symptomatic relief than histamine H 2-receptor antagonists. When administered as maintenance therapy, omeprazole reduces the incidence of relapse. The drug is also highly effective in patients poorly responsive to histamine H 2-receptor antagonists. The daily acquisition cost of omeprazole is higher than that of histamine H 2-receptor antagonists in many countries, and thus it is important to evaluate the pharmacoeconomic impact of omeprazole in the short and long term treatment of duodenal ulcer and reflux oesophagitis. Pharmacoeconomic analyses have been performed in several clinical settings using pooled data from clinical trials or simulated models of clinical practice. In a single analysis using Finnish cost data, omeprazole was more cost effective than ranitidine in the treatment of duodenal ulcer disease over a 6-month period. The cost effectiveness of omeprazole was comparable to that of sucralfate-containing regimens, with patients receiving omeprazole being healed more quickly and experiencing a greater number of healthy days. Using a computer-model simulation and Swedish cost data, omeprazole was more cost effective than ranitidine when administered as intermittent treatment of duodenal ulcer over 5 years. Preliminary reports indicate that regimens which eradicate Helicobacter pylori are more cost effective than those which do not. As short term treatment of reflux oesophagitis, omeprazole 20 to 40 mg/day was the dominating treatment strategy, being less costly and more effective than ranitidine 300 to 1200 mg/day. Omeprazole 20 mg/day produced symptom-free days more cost effectively than either cimetidine 1.6 g/day or ranitidine 300 mg/day. More importantly, as long term (maintenance or intermittent) treatment of reflux oesophagitis, omeprazole 20 mg/day was more cost effective than both ranitidine 150 mg twice daily and 'phase 1' therapy (diet and antacids) over 6 and 12 months. Thus, based on analyses evaluated, omeprazole appears to be more cost effective than ranitidine in the short term treatment of duodenal ulcer. Results for long term treatment are less clear cut, but full details from some studies are not yet available. For the short term treatment of reflux oesophagitis omeprazole is more cost effective than ranitidine or cimetidine and for long term treatment omeprazole is more cost effective than ranitidine. As treatment for reflux oesophagitis, omeprazole is considered to be the dominating treatment strategy.     

Omeprazole. A preliminary review of its pharmacodynamic and pharmacokinetic properties, and therapeutic potential in peptic ulcer disease and Zollinger-Ellison syndrome

Omeprazole is a substituted benzimidazole derivative which markedly inhibits basal and stimulated gastric acid secretion. It has a unique mode of action, irreversibly blocking the so-called proton pump of the parietal cell which is supposedly the terminal step in the acid secretory pathway. In animals, on a weight basis, omeprazole is 2 to 10 times more potent than cimetidine in inhibiting gastric acid secretion. Toxicological studies in rats have shown that very high doses of omeprazole administered for 2 years produce hyperplasia of gastric enterochromaffin-like cells and carcinoids, a few with proliferations into the submucosa. The significance of such findings to the clinical situation is wholly speculative and requires further research. Preliminary studies in patients with duodenal ulcers or Zollinger-Ellison syndrome have found no mucosal changes which would suggest that the drug represents a risk for development of carcinoid tumours at therapeutic dosages. In patients with duodenal ulcers omeprazole, at dosages of at least 20mg once daily, produced ulcer healing rates of between 60 and 100% after 2 weeks and between 90 and 100% after 4 weeks, even in patients resistant to treatment with H2-receptor antagonists. Comparative trials clearly demonstrated that omeprazole 20 to 40 mg administered once daily was significantly more effective than usual dosage regimens of cimetidine and ranitidine in healing duodenal ulcers during 2 to 4 weeks of treatment. At present no data are available evaluating omeprazole as maintenance therapy once ulcers have healed. Other clinical trials have also shown that omeprazole is effective for treating gastric ulcers, ulcerative peptic oesophagitis, and Zollinger-Ellison syndrome. In patients with Zollinger-Ellison syndrome the profound and long lasting antisecretory activity of omeprazole may make it the drug of choice for treating the massive acid hypersecretion associated with the disease, especially when H2-receptor antagonists are ineffective. During clinical trials reported to date omeprazole has been very well tolerated but further clinical experience is essential to fully evaluate its safety profile. Thus, omeprazole represents a pharmacologically unique antisecretory drug which is very effective for rapidly healing peptic ulcers and peptic oesophagitis, and for reducing gastric acid hypersecretion in patients with Zollinger-Ellison syndrome. If the apparent absence of undesirable mucosal morphological changes during treatment with usual doses in patients with peptic ulcer disease is confirmed, it may be a major advance in the treatment of these diseases.     

Omeprazole is superior to ranitidine plus metoclopramide in the short-term treatment of erosive oesophagitis

Histamine H₂-receptor antagonists are moderately effective in symptomatic treatment and healing of erosive oesophagitis, but they are not as effective as the proton pump inhibitor omeprazole. In some studies prokinetic agents seem to increase the effectiveness of H₂-antagonists, but no study comparing the efficacy of omeprazole to H₂-antagonists plus prokinetic agents has been performed. The purpose of this study was to compare the efficacy and tolerability of 20 mg omeprazole daily with 150 mg ranitidine b.d.s. plus the prokinetic agent 10 mg metoclopramide q.d.s. in patients with erosive oesophagitis. After both 4 and 8 weeks of treatment, omeprazole healed the mucosa in significantly more patients than did ranitidine plus metoclopramide. Omeprazole also provided significantly greater relief from daytime heartburn, nighttime heartburn, and acid regurgitation, and was associated with decreased concomitant antacid use. Although the overall incidence of adverse events was similar in the two treatment groups, a significantly higher number of treatment-related adverse events and more treatment-related withdrawals from the study occurred in the ranitidine plus metoclopramide treatment group. Omeprazole is more effective and better tolerated than the combination of standard dose ranitidine plus metoclopramide for patients with erosive oesophagitis.     

Rabeprazole: a review of its use in acid-related gastrointestinal disorders.

Rabeprazole is an inhibitor of the gastric proton pump. It causes dose-dependent inhibition of acid secretion and has a more rapid onset of action than omeprazole. Duodenal ulcers healed faster after treatment with rabeprazole 20 or 40 mg/day than placebo or ranitidine 150 mg 4 times daily and at a generally similar rate to omeprazole 20 mg/day in patients with duodenal ulcers; rabeprazole was similar or superior to these agents in relieving symptoms. Rabeprazole 20 and 40 mg/day healed gastric ulcers faster than placebo, and rabeprazole 20 mg/day healed ulcers at a similar healing rate, to omeprazole 20 mg/day in well controlled 6-week studies. Gastric ulcer symptom relief with rabeprazole was similar or superior to that provided by omeprazole or placebo. In 8-week studies in patients with gastro-oesophageal reflux disease (GERD), rabeprazole 10, 20 and 40 mg/day were more effective than placebo, rabeprazole 20 mg/day was more effective than ranitidine 150 mg twice daily, and rabeprazole 20 mg/day was similar in efficacy to omeprazole 20 mg/day. Symptom relief with rabeprazole in 8-week trials in patients with GERD was superior to that provided by placebo, and similar to ranitidine or omeprazole. Rabeprazole was similar to omeprazole and superior to placebo in both maintenance of healing and prevention of symptoms in patients with healed GERD in 1-year studies. One-week triple therapy with rabeprazole 20 mg twice daily plus 2 antibacterial agents achieved > or = 90% Helicobacter pylori eradication, but, as would be expected, a regimen of rabeprazole 20 mg twice daily plus 1 antibacterial agent was less successful. The drug was as effective as omeprazole and lansoprazole as part of triple therapy for H. pylori eradication. Rabeprazole successfully reduced acid output to target levels and prevented further pathological changes in 10 patients with Zollinger-Ellison syndrome. Usual dosages of rabeprazole are 20 mg/day for 4 weeks to treat duodenal ulcers, 6 weeks for gastric ulcers and 8 weeks for GERD, although some patients with duodenal ulcer may respond to a 10 mg/day dosage. For long term maintenance of GERD healing, 10 or 20 mg daily doses are adequate. Patients with hypersecretory states may need individualised dosages starting at 60 mg/day. The drug was well tolerated in clinical trials, with headache, rash, infection, diarrhoea and flu syndrome as the most common adverse events. In conclusion, rabeprazole appears to be a well tolerated proton pump inhibitor with a rapid onset of action and a low potential for drug interactions. The drug may be used to achieve healing and the relief of symptoms of duodenal ulcer, gastric ulcer and GERD, maintain GERD healing, and can form part of effective regimens to eradicate H. pylori.     

Lansoprazole. A review of its pharmacodynamic and pharmacokinetic properties and its therapeutic efficacy in acid-related disorders.

Lansoprazole is an effective acid pump inhibitor acting at the final enzymatic step of the acid secretory pathway of the parietal cell, decreasing gastric acid secretion regardless of the primary stimulus. Results of short term (less than 8 weeks) clinical trials have shown lansoprazole to be significantly superior to placebo and ranitidine in the treatment of duodenal ulcer, both in the rate of healing and in overall healing at 4 weeks. Lansoprazole appears to heal duodenal ulcer more quickly than famotidine, and demonstrates slightly greater efficacy at 4 weeks, although both drugs appear to have equivalent efficacy overall. Gastric ulcers and reflux oesophagitis are also healed by lansoprazole 30 mg/day for 4 to 8 weeks, with healing rates after 8 weeks of approximately 85 to 95% for both indications. Lansoprazole appears to be superior to ranitidine and comparable to omeprazole in treating reflux oesophagitis. Furthermore, lansoprazole has relieved reflux symptoms more quickly than either ranitidine or omeprazole. Preliminary data also indicate that lansoprazole may be effective in the treatment of peptic ulcer disease and reflux oesophagitis refractory to H2-receptor antagonists, and in patients with Zollinger-Ellison syndrome. While direct comparisons with omeprazole are limited, results suggest that lansoprazole, used for short term treatment, is at least as effective as omeprazole in the treatment of peptic ulcer and reflux oesphagitis. Lansoprazole has been well tolerated in short term clinical trials, with an incidence of adverse effects comparable with that of other agents in its therapeutic class. Trials assessing long term tolerability data are ongoing and will be required as part of the assessment of the safety profile, if lansoprazole is to be used prophylactically to prevent ulcer recurrence. Thus, by virtue of its ability to heal ulcers and rapidly relieve associated symptomatology, lansoprazole represents a useful alternative for the treatment of acid related disorders.     

Omeprazole in peptic ulcers resistant to histamine H2-receptor antagonists

Eighteen patients with duodenal, gastric or jejunal ulcers, resistant to at least 3 months treatment with histamine H2-receptor antagonists, singly or in combination with other anti-ulcer drugs, were treated with 40 mg omeprazole once daily for up to 8 weeks. All ulcers healed, the majority within two weeks. After ulcer healing patients were given maintenance therapy with high doses of cimetidine or ranitidine. Of 15 patients on maintenance therapy with H2-receptor antagonists, 12 (80%) developed a relapse after a period ranging from 3 to 52 weeks. Two patients were lost to follow-up. After re-healing on 40 mg omeprazole, two patients were given 20 mg omeprazole daily as maintenance therapy but relapses occurred again after 14 and 26 weeks respectively. After re-healing on 40 mg omeprazole, these two patients and one additional patient received maintenance therapy with 40 mg omeprazole daily. At present these three patients have been relapse-free for periods varying from 16 to 52 weeks. No side effects were registered during treatment with omeprazole. It is therefore concluded that omeprazole is highly effective in healing refractory peptic ulcers and that omeprazole maintenance therapy may be useful for prevention of relapse. Patients are sometimes seen with peptic ulceration which appears resistant to therapy with histamine H2-receptor antagonists, colloidal bismuth subcitrate, sucralfate or pirenzepine, either given as monotherapy for a prolonged period of time or as combination therapy. Usually the reason for such therapeutic failure remains obscure. Whether virtually total abolition of acid secretion will allow ulcer healing in these circumstances is unknown.(ABSTRACT TRUNCATED AT 250 WORDS)     

Lansoprazole: pharmacokinetics, pharmacodynamics and clinical uses

Lansoprazole (Prevacid, TAP Pharmaceuticals, Inc.) is a substituted benzimidazole that inhibits gastric acid secretion. This agent is approved for the short-term treatment of erosive reflux oesophagitis, active gastric ulcer, active duodenal ulcer and the treatment of non-steroidal anti-inflammatory drug (NSAID)-induced gastric and duodenal ulcers. It is also approved for the long-term treatment of healed reflux oesophagitis, healed duodenal ulcer, the treatment of hypersecretory conditions such as Zollinger-Ellison syndrome and the eradication of Helicobacter pylori as a component of triple therapy with lansoprazole, clarithromycin and amoxicillin, or dual therapy with lansoprazole and amoxicillin. Its mechanism of action is to selectively inhibit the membrane enzyme H+/K+ ATPase in gastric parietal cells. In clinical trials, lansoprazole is more effective than placebo or histamine (H2)-receptor antagonists in the treatment of reflux oesophagitis. Lansoprazole administered at a dose of 30 mg daily produced faster relief of symptoms and superior healing rates in patients with gastric or duodenal ulcers or reflux oesophagitis than H2-receptor antagonists. A daily dose of 30 mg lansoprazole reduced epigastric pain faster than omeprazole 20 mg daily in patients with peptic ulcer disease but healing rates at 4 and 8 weeks were similar with both agents at these dosages. Lansoprazole was more effective than H2-receptor antagonists in patients with Zollinger-Ellison syndrome and produced similar treatment outcome to omeprazole. Lansoprazole in combination with clarithromycin and amoxicillin produced similar rates of eradication of H. pylori. In clinical trials, lansoprazole is well-tolerated and has a low frequency of side effects similar to that of H2-receptor antagonists or omeprazole.     

Lansoprazole: pharmacokinetics,pharmacodynamics and clinical uses

Lansoprazole (Prevacid?, TAP Pharmaceuticals, Inc.) is a substituted benzimidazole that inhibits gastric acid secretion. This agent is approved for the short-term treatment of erosive reflux oesophagitis, active gastric ulcer, active duodenal ulcer and the treatment of non-steroidal anti-inflammatory drug (NSAID)-induced gastric and duodenal ulcers. It is also approved for the long-term treatment of healed reflux oesophagitis, healed duodenal ulcer, the treatment of hypersecretory conditions such as Zollinger-Ellison syndrome and the eradication of Helicobacter pylori as a component of triple therapy with lansoprazole, clarithromycin and amoxicillin, or dual therapy with lansoprazole and amoxicillin. Its mechanism of action is to selectively inhibit the membrane enzyme H⁺/K⁺ATPase in gastric parietal cells. In clinical trials, lansoprazole is more effective than placebo or histamine (H₂)-receptor antagonists in the treatment of reflux oesophagitis. Lansoprazole administered at a dose of 30 mg daily produced faster relief of symptoms and superior healing rates in patients with gastric or duodenal ulcers or reflux oesophagitis than H₂-receptor antagonists. A daily dose of 30 mg lansoprazole reduced epigastric pain faster than omeprazole 20 mg daily in patients with peptic ulcer disease but healing rates at 4 and 8 weeks were similar with both agents at these dosages. Lansoprazole was more effective than H₂-receptor antagonists in patients with Zollinger-Ellison syndrome and produced similar treatment outcome to omeprazole. Lansoprazole in combination with clarithromycin and amoxicillin produced similar rates of eradication of H. pylori. In clinical trials, lansoprazole is well-tolerated and has a low frequency of side effects similar to that of H₂-receptor antagonists or omeprazole.     

Time course of inhibition of gastric acid secretion by omeprazole and ranitidine in gastric fistula rats

Basal, pentagastrin- and histamine-stimulated acid secretion were measured in gastric fistula rats treated with the H+/K(+)-ATPase inhibitor, omeprazole, and the H2-receptor antagonist, ranitidine. All doses of omeprazole (20, 30, 40, 80, 400 mumol/kg) and ranitidine (125, 187.5, 250, 375 mumol/kg) essentially abolished the basal acid output for various periods of time. Omeprazole, 80 mumol/kg, administered twice daily, reduced the 24-h basal acid secretion more effectively than did 400 mumol/kg given once daily. Four daily administrations of ranitidine reduced the 24-h basal acid output to a similar extent as omeprazole administered twice. Omeprazole (20, 80 mumol/kg) was more effective than ranitidine (125, 375 mumol/kg) in inhibiting acid secretion evoked by maximal doses of pentagastrin (650 nmol/kg per h) and histamine dihydrochloride (136 mumol/kg), whereas this difference was less pronounced for the inhibition of acid responses induced by a threshold dose (1.1 mumol/kg) of histamine. The inhibition evoked by omeprazole (80 mumol/kg x 2) and ranitidine (375 mumol/kg x 4) of basal and histamine (1.1 and 136 mumol/kg)-induced acid secretion was similar after 1 and 4 weeks of treatment. After the end of drug administration, the acid secretion induced by threshold doses of histamine was significantly elevated in the omeprazole-treated rats, whereas no significant hypersecretion of acid was seen during the recovery period in rats treated with ranitidine. Plasma gastrin concentrations were significantly elevated after 4 weeks of treatment with omeprazole but returned to pretreatment levels after 4 weeks of recovery.(ABSTRACT TRUNCATED AT 250 WORDS)     

Lansoprazole: A Comprehensive Review

Lansoprazole is the second member of the substituted benzimidazole class of antisecretory agents approved for use in the United States. These drugs decrease parietal cell acid secretion by inhibiting H⁺,K⁺-adenosine triphosphatase, the final step in the secretion of acid. Lansoprazole has been studied extensively for the short-term treatment of duodenal and gastric ulcers, reflux esophagitis, and Helicobacter pylori-positive peptic ulcer disease; long-term treatment of Zollinger-Ellison syndrome; and maintenance treatment of erosive esophagitis. A dosage of 30 mg/day produced higher healing rates and equivalent or faster relief of ulcer symptoms than ranitidine or famotidine in patients with duodenal or gastric ulcers and reflux esophagitis. Compared with omeprazole 20 mg/day, that dosage provided faster epigastric pain relief in these patients after 1 week, although healing rates for the two agents were equivalent at 4 and 8 weeks. In patients with peptic ulcer refractory to 8-week therapy with histamine₂-receptor antagonists, healing rates were not significantly different between lansoprazole and omeprazole. In patients with Zollinger-Ellison syndrome, lansoprazole was superior to histamine₂-receptor antagonists and was similar in efficacy, safety, and duration of action to omeprazole. Combinations of lansoprazole or omeprazole with one or two antibiotics produced equivalent eradication of H. pylori. In clinical trials, lansoprazole was well tolerated, with frequency of adverse effects similar to that reported with ranitidine, famotidine, and omeprazole.     

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.     

Rabeprazole: an update of its use in acid-related disorders.

Rabeprazole is an inhibitor of the gastric proton pump. It causes dose-dependent inhibition of acid secretion. In 8-week studies, among patients with gastro-oesophageal reflux disease (GORD), rabeprazole 20 mg/day or 10mg twice daily was as effective as omeprazole and superior to ranitidine in the healing of GORD. Symptom relief with rabeprazole was superior to that provided by placebo and ranitidine and similar to omeprazole. In long-term trials rabeprazole 10 mg/day was similar to omeprazole 20 mg/day in a 2-year study and superior to placebo in 1-year studies, in both the maintenance of healing and prevention of symptoms in patients with healed GORD. In nonerosive GORD, 4-week studies have shown rabeprazole to be more effective than placebo in relieving heartburn and various other gastrointestinal symptoms. Data among patients with Barrett's oesophagus suggest rabeprazole 20 mg/day may be more effective than placebo in maintaining healing of associated oesophagitis after 1 year of treatment. One-week triple Helicobacter pylori eradication therapy with rabeprazole plus clarithromycin and amoxicillin achieved eradication rates of > or =85%. Rabeprazole is as effective as omeprazole and lansoprazole when included as part of a triple-therapy regimen for the eradication of H. pylori. Eradication rates of >90% were achieved when rabeprazole 20 to 40 mg/day was included as part of a quadruple eradication regimen. As monotherapy for peptic ulcer healing and symptom relief, 4- to 8-week studies have shown rabeprazole 10 to 40 mg/day to be superior to placebo and ranitidine and have similar efficacy to omeprazole. Preliminary 1-year data among 16 patients with Zollinger-Ellison syndrome suggest rabeprazole 60 to 120 mg/day can resolve and prevent the recurrence of symptoms and endoscopic lesions associated with this condition. In clinical trials of up to 2 years' duration the tolerability of rabeprazole is similar to that of placebo, ranitidine and omeprazole. Common adverse events assigned to rabeprazole have been diarrhoea, headache, rhinitis, nausea, pharyngitis and abdominal pain. Histological changes and increases in serum gastrin levels were unremarkable and typical of proton pump inhibitors. No dosage adjustment is necessary in renal and mild to moderate hepatic impairment. CONCLUSION: Rabeprazole is a well tolerated proton pump inhibitor. It has proven efficacy in healing, symptom relief and prevention of relapse of peptic ulcers and GORD and can form part of effective H. pylori eradication regimens. It is an important alternative to H(2) antagonists and an additional treatment option to other proton pump inhibitors in the management of acid-related disorders.     

Ranitidine: a pharmacoeconomic evaluation of its use in acid-related disorders

Ranitidine is a histamine H 2-receptor antagonist which, on the basis of its well established tolerability and efficacy profile, has been widely prescribed for the treatment of ulcer disease and mild to moderate reflux oesophagitis. However, the advent of more powerful gastric acid inhibitors (e.g. acid pump inhibitors) and the realisation of the role of Helicobactor pylori infection in duodenal ulcer disease could have considerable clinical and economic implications for the use of ranitidine (and other H 2-receptor antagonists). Simulation modelling studies based on current pricing policies in Europe predict that ranitidine-based treatment will be less cost effective than omeprazole in the short term healing of duodenal ulcer and reflux oesophagitis disease. During longer term treatment, omeprazole is expected to be the dominating strategy over ranitidine-based therapy in Europe and the US. However, the inherent limitations of modelling studies reinforce the need for randomised prospective trials, preferably conducted in a general practice setting and including a quality-of-life analysis. Of the currently accepted approaches for the long term management of recurrent duodenal ulcer disease, daily maintenance therapy with ranitidine has been shown to be more cost effective than intermittent treatment for up to 2 years in the US. The annual cost of providing continuous maintenance therapy with ranitidine 150 mg/day is higher than with cimetidine 400 mg/day, although the extra benefits include a reduced risk of pain and discomfort from an expected lower rate of ulcer recurrence with ranitidine. Simultaneous ulcer healing and eradication of H. pylori markedly reduces relapse rates and is likely to become the management strategy of choice in H. pylori-positive patients, particularly with the advent of more convenient, well tolerated and effective regimens. Moreover, widespread clinical acceptance of H. pylori eradication may yield substantial cost savings to society by reducing the overall need for long term antisecretory therapy. Nonetheless, maintenance therapy with histamine H 2-receptor antagonists remains indicated for patients at high risk of ulcer recurrence who are poorly responsive to or cannot tolerate H. pylori eradication regimens. In summary, the proven efficacy and tolerability of ranitidine will ensure its continued use in the treatment of many patients with duodenal ulcer and mild to moderate reflux oesophagitis. However, there is increasing clinical and economic data favouring the selection of omeprazole in patients with more severe symptoms of these diseases.(ABSTRACT TRUNCATED AT 400 WORDS)     

A prospective study of the effectiveness of low dose omeprazole as initial therapy in Zollinger–Ellison syndrome

Background: The proton pump inhibitors (omeprazole and lansoprazole) are the drugs of choice for the medical management of gastric acid hypersecretion in Zollinger–Ellison syndrome (ZES). These drugs are safe for long-term therapy but are acid-labile and high doses are expensive. The recommended starting dose of omeprazole is 60 mg/day. However, it has been shown in recent studies that the maintenance dose of omeprazole could be safely reduced to 20 mg once or twice a day in more than two-thirds of patients with ZES. The purpose of this study is to determine if an initial starting dose of omeprazole 20 mg/day is safe and effective in patients with ZES. Methods: Forty-nine consecutive patients with ZES being treated with ranitidine for at least 2 weeks were admitted to the NIH. Omeprazole 20 mg was started on day 1 of the admission and ranitidine discontinued 4 h after the first dose. Gastric acid output was measured for 1 h prior to the next omeprazole dose on day 2, then on day 3 if the value was > 10 mmol/h on the previous day. If acid-peptic symptoms developed or the gastric acid output remained > 10 mmol/h on day 3, the patient was considered to have failed omeprazole 20 mg/day initial therapy and the dose titrated daily to achieve adequate control of acid-peptic symptoms and gastric secretion. Results: In 33 of the 49 patients (68%) omeprazole 20 mg/day was successful as initial therapy. Sixteen patients (32%) failed this initial omeprazole dose (eight patients owing to persistent peptic symptoms and eight patients owing to inadequate acid control). The final daily omeprazole dose required in these patients was 40 mg in eight patients (16%), 60 mg in one patient (2%) and 80 mg in seven patients (14%). Basal acid output (BAO) was the only clinical or laboratory feature that was significantly different between the two groups in which low dose initial omeprazole therapy was or was not successful: all patients with basal acid output < 20 mmol/h had a successful outcome. Conclusions: Because of the need to rapidly control gastric acid hypersecretion owing to the high risk of complications from peptic ulcer disease, patients with ZES should continue to be started on omeprazole 60 mg/day and the dose adjusted by acute titration methods as is currently recommended. After a maintenance dose is established, attempts should be undertaken to reduce the dose to 20 mg/day once or twice a day. Only the minority of patients with ZES in whom basal acid output is known to be < 20 mmol/h (20% of patients) should be started on a low initial omeprazole dose.     

Systematic review: the efficacy of intermittent and on-demand therapy with histamine H2-receptor antagonists or proton pump inhibitors for gastro-oesophageal reflux disease patients

AIM: To perform a systematic review on the efficacy of intermittent and on-demand therapy with either histamine H2-receptor antagonists or proton pump inhibitors for patients with erosive oesophagitis or symptomatic heartburn. METHOD: We conducted randomized-controlled trials of non-continuous therapy in gastro-oesophageal reflux disease patients. RESULTS: Fourteen studies met inclusion criteria. Because of variation in outcome measures statistical pooling of results was not possible. Results were analysed qualitatively. Four studies evaluated intermittent therapy of treatment 3 days a week with omeprazole 20 mg or daily with ranitidine which were not efficacious compared to a daily proton pump inhibitor. Famotidine 10 and 20 mg, ranitidine 75 mg and cimetidine 200 mg were efficacious in five on-demand studies for relief of symptomatic heartburn episodes. In three of four studies, evaluating only non-erosive (endoscopy-negative) gastro-oesophageal reflux disease patients, esomeprazole 20 and 40 mg and omeprazole 10 and 20 mg a day were efficacious using willingness to continue as an endpoint. Lansoprazole 30 mg and omeprazole 20 mg maintained symptom control in 60-70% of healed oesophagitis patients. CONCLUSIONS: Intermittent proton pump inhibitor or H2-receptor antagonist therapy is not effective in maintaining control in oesophagitis patients. H2-receptor antagonists are effective for relief of heartburn episodes. On-demand proton pump inhibitor therapy may work in a proportion of non-erosive gastro-oesophageal reflux disease patients.     

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

Famotidine is a highly selective histamine H2-receptor antagonist. In healthy volunteers and patients with acid hypersecretory disease it is approximately 20 to 50 times more potent at inhibiting gastric acid secretion than cimetidine and 8 times more potent than ranitidine on a weight basis. As shown in placebo-controlled trials, famotidine is effective in healing both duodenal and gastric ulcers. Famotidine 20mg twice daily or 40mg at bedtime achieves healing rates and symptom relief similar or superior to those achieved by cimetidine 800mg daily or ranitidine 300mg daily in patients with peptic ulcer disease. Results of 1 placebo-controlled study suggest that famotidine prevents recurrence of duodenal ulcer, but comparative trials are needed to establish its relative efficacy in maintenance therapy. The few non-comparative trials conducted to date also suggest that famotidine 10 to 20mg twice daily may be effective in the treatment of gastritis and reflux gastro-oesophagitis. In comparative trials, famotidine was similar in efficacy to cimetidine in the treatment of upper gastrointestinal bleeding and to ranitidine in the prevention of pulmonary aspiration of acid. In patients with Zollinger-Ellison syndrome, the potency and long duration of action of famotidine may confer an advantage over other H2-receptor antagonists--in individualised doses (mean 0.33 g/day) famotidine successfully controlled acid secretion for up to 72 months in 1 study of such patients. Accumulated clinical evidence confirms that famotidine is very well tolerated and is free of the antiandrogenic effects infrequently reported with cimetidine. Moreover, famotidine is not associated with altered hepatic metabolism of drugs. Thus, famotidine is an effective, well-tolerated alternative to cimetidine and ranitidine. Famotidine is also promising as maintenance therapy for preventing recurrence of duodenal ulcer and as initial or maintenance treatment of gastric hypersecretory disorders, but further clinical experience, particularly in the long term, is needed to define the relative efficacy and tolerability of famotidine in these indications.     

Omepmazole or high-dose ranitidine in the treatment of patients with reflux oesophagitis not responding to ''standard doses''of H2-receptor antagonists

Ninety-eight patients (26 females), who presented with erosive and/or ulcerative oesophagitis, despite at least a 3-month period of treatment with standard doses of cimetidine (greater than or equal to 1200 mg daily) or ranitidine (greater than or equal to 300 mg daily), were included in a double-blind, randomized trial to compare omeprazole (40 mg o.m.) with a high dose of ranitidine (300 mg b.d.). The treatment was given for 4-12 weeks; endoscopy assessment and laboratory screening were performed on entry to the trial and thereafter every fourth week. Endoscopic healing was defined as complete epithelialization of all macroscopic erosions or ulcers in the squamous epithelium. An 'intention-to-treat' analysis of the clinical data revealed omeprazole to be superior to ranitidine: 63% of those patients who were given omeprazole were healed endoscopically after a 4-week period of treatment, compared with only 17% of those given ranitidine. This difference in healing rate persisted during the 12-week study period (90% vs 47% after 12 weeks; P less than 0.0001). Reflux symptoms were more rapidly and completely relieved with omeprazole: heartburn resolved completely in 86% of patients treated with omeprazole for 4 weeks compared with 32% in the ranitidine group (P less than 0.0001). The mean basal gastrin concentrations increased only in those given omeprazole from 18.9 pmol/L at pre-entry to a mean value of 31.7 pmol/L on the last day of omeprazole administration. In ranitidine-treated patients no significant increase in basal gastrin concentration was observed. Both drugs were well tolerated with few adverse events, which were mainly mild and transient. These results demonstrate the superiority of omeprazole over a high dose of ranitidine in the treatment of resistant reflux oesophagitis.     

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 H2-receptor blockade by ranitidine on ulcer healing and gastric acid secretion in patients with gastric and duodenal ulcers

The effect of treatment for 4 weeks with the H2-receptor antagonist ranitidine 200 mg daily on ulcer healing, clinical symptoms and antacid consumption, and on gastric acid secretion, was studied in a double blind trial in 48 patients with a total of 50 endoscopically confirmed duodenal, prepyloric or corporeal gastric ulcer. Patients whose ulcers did not show complete healing within 28 days were continued openly on ranitidine for up to a further 4 weeks. Endoscopy, basal gastric acid secretion (BAO) and pentagastrin-stimulated maximal secretion (PAO) studies were performed at 2-week intervals. After four weeks, 73% of the gastro-duodenal ulcers in the ranitidine group showed complete healing versus 42% in the placebo group (p less than 0.05). Gastric acid secretion was considerably inhibited both under basal (89%; p less than 0.001) and maximal challenge (71%; p less than 0.001) conditions. The inhibitory effect was still pronounced 13-15 h after administration of ranitidine 100 mg. Symptoms and the need for antacids were significantly reduced. Ranitidine appears to be an efficacious, safe and well tolerated medicine principle for the treatment of gastro-duodenal ulcer disease.     

Lansoprazole: an update of its place in the management of acid-related disorders

Lansoprazole is an inhibitor of gastric acid secretion and also exhibits antibacterial activity against Helicobacter pylori in vitro. Current therapy for peptic ulcer disease focuses on the eradication of H. pylori infection with maintenance therapy indicated in those patients who are not cured of H. pylori and those with ulcers resistant to healing. Lansoprazole 30 mg combined with amoxicillin 1g, clarithromycin 250 or 500mg, or metronidazole 400 mg twice daily was associated with eradication rates ranging from 71 to 94%, and ulcer healing rates were generally >80% in well designed studies. In addition, it was as effective as omeprazole- or rabeprazole-based regimens which included these antimicrobial agents. Maintenance therapy with lansoprazole 30 mg/day was significantly more effective than either placebo or ranitidine in preventing ulcer relapse. Importantly, preliminary data suggest that lansoprazole-based eradication therapy is effective in children and the elderly. In the short-term treatment of patients with gastro-oesophageal reflux disease (GORD), lansoprazole 15, 30 or 60 mg/day was significantly more effective than placebo, ranitidine 300 mg/day or cisapride 40 mg/day and similar in efficacy to pantoprazole 40 mg/day in terms of healing of oesophagitis. Lansoprazole 30 mg/day, omeprazole 20 mg/day and pantoprazole 40 mg/day all provided similar symptom relief in these patients. In patients with healed oesophagitis. 12-month maintenance therapy with lansoprazole 15 or 30 mg/day prevented recurrence and was similar to or more effective than omeprazole 10 or 20 mg/day. Available data in patients with NSAID-related disorders or acid-related dyspepsia suggest that lansoprazole is effective in these patients in terms of the prevention of NSAID-related gastrointestinal complications, ulcer healing and symptom relief. Meta-analytic data and postmarketing surveillance in >30,000 patients indicate that lansoprazole is well tolerated both as monotherapy and in combination with antimicrobial agents. After lansoprazole monotherapy commonly reported adverse events included dose-dependent diarrhoea, nausea/vomiting, headache and abdominal pain. After short-term treatment in patients with peptic ulcer, GORD, dyspepsia and gastritis the incidence of adverse events associated with lansoprazole was generally < or = 5%. Similar adverse events were seen in long-term trials, although the incidence was generally higher (< or = 10%). When lansoprazole was administered in combination with amoxicillin, clarithromycin or metronidazole adverse events included diarrhoea, headache and taste disturbance. In conclusion, lansoprazole-based triple therapy is an effective treatment option for the eradication of H. pylori infection in patients with peptic ulcer disease. Preliminary data suggest it may have an important role in the management of this infection in children and the elderly. In the short-term management of GORD, lansoprazole monotherapy offers a more effective alternative to histamine H2-receptor antagonists and initial data indicate that it is an effective short-term treatment option in children and adolescents. In adults lansoprazole maintenance therapy is also an established treatment option for the long-term management of this chronic disease. Lansoprazole has a role in the treatment and prevention of NSAID-related ulcers and the treatment of acid-related dyspepsia; however, further studies are needed to confirm its place in these indications. Lansoprazole has emerged as a useful and well tolerated treatment option in the management of acid-related disorders.