24 hour intragastric acidity during maintenance treatment with ranitidine

Degrees of acid suppression and ulcer healing: dosage considerations

The human stomach has a normal circadian rhythm of intragastric acidity characterized by increasing acidity during the day and peaks in the early hours of the morning. Eating causes a transient decrease of intragastric acidity. Acid appears to be the permissive factor in peptic ulcer disease and to be responsible for symptoms; the patient with duodenal ulcer may secrete too much acid. Pharmacological control of gastric acid secretion will speed ulcer healing. Modern regimens, which typically use a bedtime dose of an H2-receptor antagonist, produce a pulse of decreased acidity. Intragastric acidity is decreased during the night and early morning, leaving a normal profile of acidity during the day and early evening. Higher or more frequent doses of an antisecretory agent can produce a more profound decrease of 24-h intragastric acidity. Theoretical problems associated with a sustained or profound decrease of 24-h intragastric acidity include the threat of enteric infection and infestation, potential bacterial overgrowth with possible N-nitrosamine formation, and drug-induced hypergastrinaemia. In light of these potential problems, for the management of simple peptic ulceration, it appears sensible to use the minimum intervention required. Bedtime H2-receptor blockade is one such regimen. The more potent antisecretory regimens can be used for difficult clinical problems such as the Zollinger-Ellison syndrome, intractable duodenal ulceration, and severe oesophagitis.

Tolerance during 5 months of dosing with ranitidine, 150 mg nightly: a placebo-controlled, double-blind study

Repeated dosing with an H2-receptor antagonist results in a modest decrease in antisecretory potency termed "tolerance." The object of this prospective study was to determine whether tolerance is a progressive phenomenon or whether it levels off during prolonged dosing with a standard maintenance dose of an H2-antagonist. The effect of continuous dosing with ranitidine, 150 mg nightly, was compared with intermittent dosing (27 days of placebo each month) with active ranitidine, 150 mg nightly, only on the night of each experiment. Simultaneous 24-hour intragastric acidity and plasma gastrin concentration were measured monthly for 5 months in 17 healthy subjects (7 continuous and 10 intermittent dosing). In the intermittent-dosing group, the antisecretory response to ranitidine, 150 mg nightly, was preserved throughout the 141-day trial period; the median nocturnal integrated acidity decreased from 557 mmol.h/L (day 0) to 38 mmol.h/L on day 1 of dosing, and it ranged between 32 and 55 (median, 45) mmol.h/L during days 29-141. In the continuous-dosing group, there was a significant return of nocturnal intragastric acidity on days 29 and 85 compared with day 1 of dosing. The median nocturnal integrated acidity decreased in the continuous-dosing group from 554 mmol.h/L (day 0) to 87 mmol.h/L on the first day of dosing, and it ranged between 145 and 287 (median, 170) mmol.h/L during days 29-141. Either intermittent or continuous dosing with ranitidine was associated with an elevation of plasma gastrin concentration, which remained constant throughout the 5-month study. Tolerance does develop in healthy subjects during the first month of dosing with ranitidine, 150 mg nightly, but it is not a progressive phenomenon, and it is probably not of clinical relevance.

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.

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.

A comparison of roxatidine acetate 150 mg once daily and 75 mg twice daily in gastric ulcer healing

In 363 outpatients with endoscopically confirmed gastric ulcers the efficacy and safety of roxatidine acetate 150 mg at night was compared to 75 mg twice daily. After 8 weeks' treatment substantial reductions in gastric ulcer diameter were obtained in addition to healing rates of 83.7 and 86% for the twice daily and night-time dosing, respectively. Daily reductions in day and night-time epigastric pain were obtained with no significant differences between treatment groups for pain scores or antacid tablet consumption. Furthermore, cigarette smoking did not influence the healing rates produced by either treatment schedule. 26 patients reported 32 adverse reactions and 5 patients discontinued treatment because of side effects, although only 1 of these was a severe reaction. The present data suggest that a single night-time dose of roxatidine acetate 150 mg is as safe and effective as the twice daily dose regimen for the management of acute gastric ulceration.

Acute treatment of duodenal ulcer: a multicentre study to compare ranitidine 150 mg twice daily with ranitidine 300 mg once at night

A randomised double blind clinical trial was undertaken in the UK and Ireland to compare ranitidine 300 mg given as a single bed time tablet with ranitidine 150 mg twice daily in the acute treatment of duodenal ulcers. Of the 594 patients with endoscopically diagnosed duodenal ulcer entered into the trial, 424 patients had complete endoscopic findings on which healing rates at four weeks were determined. By this time 156 of 201 (78%) patients healed with ranitidine 300 mg nocte compared with 186 of 223 (83%) receiving ranitidine 150 mg twice daily (p = 0.28). After eight weeks of treatment 97% of the patients in each group were healed. The healing rates for smokers and non-smokers did not differ significantly at either four or eight weeks. Each regimen was equally effective in reducing day and night-time pain. Adverse events were reported in 23 patients overall; 12 were withdrawn from the trial. Minor abnormalities in liver function tests were noted in three patients. The trial confirmed that a single dose of ranitidine 300 mg given at night is a safe, effective alternative treatment to ranitidine 150 mg bd for the acute treatment of duodenal ulcer.