Nocturnal intragastric acidity after over-the-counter doses of famotidine, ranitidine or placebo

Acid peptic diseases: pharmacological approach to treatment

Acid peptic disorders are the result of distinctive, but overlapping pathogenic mechanisms leading to either excessive acid secretion or diminished mucosal defense. They are common entities present in daily clinical practice that, owing to their chronicity, represent a significant cost to healthcare. Key elements in the success of controlling these entities have been the development of potent and safe drugs based on physiological targets. The histamine-2 receptor antagonists revolutionized the treatment of acid peptic disorders owing to their safety and efficacy profile. The proton-pump inhibitors (PPIs) represent a further therapeutic advance due to more potent inhibition of acid secretion. Ample data from clinical trials and observational experience have confirmed the utility of these agents in the treatment of acid peptic diseases, with differential efficacy and safety characteristics between and within drug classes. Paradigms in their speed and duration of action have underscored the need for new chemical entities that, from a single dose, would provide reliable duration of acid control, particularly at night. Moreover, PPIs reduce, but do not eliminate, the risk of ulcers in patients taking NSAIDs, reflecting untargeted physiopathologic pathways and a breach in the ability to sustain an intragastric pH of more than 4. This review provides an assessment of the current understanding of the physiology of acid production, a discussion of medications targeting gastric acid production and a review of efficacy in specific acid peptic diseases, as well as current challenges and future directions in the treatment of acid-mediated diseases.

Review article: treatment of mild and severe cases of GERD

GERD prevalence continues to rise in contrast to peptic ulcer disease. The spectrum contains reflux esophagitis and so-called 'endoscopy-negative GERD' or 'non-erosive GERD' (NERD) or S-GERD and patients with 'normal' overall 24-h esophageal acidification but with a high 'symptom-index'. The majority of reflux patients will not need endoscopy initially. Prompt referral for endoscopy is indicated only if the patient has atypical symptoms or alarm symptoms such as dysphagia, anemia, weight loss, severe abdominal pain, or pain that does not respond to acid neutralization or suppression, or develops symptoms after the age of 50 years. Antireflux therapy consist of raising the head of the bed, maintaining normal weight, and avoidance of foods and drugs that precipitate symptoms, together with antacids or over-the-counter H(2) receptor antagonists (H(2)RAs). If symptoms persist after these simple measures or if antacids or H(2)RAs are needed quite often, then a more formal first-line treatment should be started. Many experts feel that a stepdown approach instead of a stepup approach is clinically and economically a more appropriate way of installing such first-line therapy. Physicians increasingly consider prescribing a (low- or standard dose) once-a-day proton pump inhibitor (PPI) as firstline therapy. If symptoms recur after 4-week trial or are in sufficiently relieved, then the patient should be referred for endoscopy. Endoscopy may reveal no abnormalities (NERD) or evidence of reflux-induced damage. Treatment of endoscopy-negative reflux disease should be directed towards rapid relief of symptoms and then maintenance of relief using minimum effective therapy. Responses to PPIs are somewhat lower in endoscopy-negative patients compared to esophagitis. Some form of long-term therapy is needed in the majority of patients. 'On demand' PPI therapy to control reflux symptoms is a new and attractive option. The goal of treatment of GERD should be to relieve symptoms and to heal lesions. Symptom severity and much less endoscopic abnormalities, drives the therapy. When symptoms are mild or intermittent and when esophagitis is absent or minimal, standard dose PPI is usually reinstituted. If there is moderate or severe esophagitis or if symptoms are particularly troublesome, then the patient should start again with standard-dose PPI therapy once a day, but not uncommonly a b.i.d. dosage maybe necessary. Once a dose of the acid suppressant that relieves symptoms is found, this dose should be maintained for a period of 3 months. After this time, an attempt should be made to reduce the dose. A plan should be formulated for long-term treatment.

A study of the nonprescription drug consumer's understanding of the ranitidine product label and actual product usage patterns in the treatment of episodic heartburn

INTRODUCTION

A study of the consumer's understanding of the product label instructions and the resulting product use were conducted to support the switch of a product from prescription to nonprescription status. H2 receptor antagonists have recently been approved for nonprescription use. This study evaluated the consumer's understanding of the product label for ranitidine hydrochloride (Zantac 75) and the product usage pattern in the treatment of episodic heartburn.

OBJECTIVES

Our objectives were to evaluate each aspect of the communication of labeled indications, contraindications, and directions for use of two label formats (old and new) for a new nonprescription preparation of ranitidine (Zantac) and to evaluate nonprescription consumers' use of ranitidine 75-mg tablets (as Zantac 75) in a medically unsupervised, at-home setting to observe whether these consumers used the product appropriately and followed directions as written on the package label.

METHODS

Adult male and female consumers (n = 1405) in a shopping mall environment who were attracted to a poster asking, "Do you have stomach problems?" were recruited for the label comprehension phase (two different label formats) and the 3-week usage phase if after reading the Zantac 75 package label they decided the product was appropriate for them. No instructions regarding the use of Zantac 75 were provided beyond what was printed on the package label. Subjects recorded use in a diary and tablet counts were performed at the end of the study period. A medical history was also taken at this time and an assessment of product use was performed by a physician.

RESULTS

In at least 84% of all subjects, both formats were effective in the communication of label objectives for the contraindication against concurrent prescription stomach ulcer medication, maximum daily dose, and maximum duration of dosing at maximum daily doses. The direction to take one tablet per dose was adhered to by 90% of consumers, and 90% of consumers followed the instructions to take no more than two tablets in 24 hours. Ninety-six percent of consumers complied with the direction not to take the maximum daily dose for more than 14 consecutive days. Notably, the maximum daily dose was taken for < or =3 consecutive days by 79% of consumers. The most frequently reported adverse events were headache, acute nasopharyngitis, upper respiratory tract infection, diarrhea, nausea, and menstrual cramps.

CONCLUSION

The study demonstrated that the vast majority of a large sample of unsupervised consumers understood the package label and fully complied with the package directions by not exceeding the maximum daily dosage and length of use. Nonprescription consumers safely used Zantac 75 without medical supervision.

Control of intragastric acidity with over-the-counter doses of ranitidine or famotidine

BACKGROUND

Histamine H2-receptor antagonists are available over the counter for the treatment of heartburn.

AIM

To compare the effects of low doses of ranitidine and famotidine on intragastric acidity in a three-way crossover study.

METHODS

Healthy subjects (12 male, 12 female) were dosed on three occasions with single oral doses of placebo, ranitidine, 75 mg, and famotidine, 10 mg, 1 h after lunch. The pH of gastric aspirates was then measured for 20 h. Subjects ate standard meals and snacks. Analysis of variance was used to determine the statistical significance of differences in acidity (mmol/L) during the day (12.30-22.30 hours) and night (22.30-08.30 hours).

RESULTS

Ranitidine and famotidine were superior (P < 0.05) to placebo in decreasing acidity for daytime and night-time intervals. There were no significant differences in mean gastric acidity between ranitidine and famotidine during the daytime (11.37 mmol/L vs. 13.42 mmol/L, respectively) and night-time (23.57 mmol/L vs. 24.74 mmol/L, respectively). Intragastric acidity after ranitidine was significantly lower than that after famotidine in the first 2.5-h period following dosing (4.32 mmol/L vs. 9.28 mmol/L; P < 0.05).

CONCLUSIONS

Lunchtime doses of ranitidine and famotidine decreased acidity during day- and night-time periods. The effect of ranitidine was significantly greater for the first 2.5 h after dosing.

Pharmacological and pharmacodynamic essentials of H(2)-receptor antagonists and proton pump inhibitors for the practising physician

The suppression of gastric acid secretion with anti-secretory agents has been the mainstay of medical treatment for patients with acid-related disorders. Although the majority of Helicobacter pylori -related peptic ulcers can be healed with antibiotics, ulcer healing and symptom control can be significantly improved when antibiotics are given with anti-secretory agents, especially with a proton pump inhibitor. There is a dynamic relationship between the suppression of intragastric acidity and the healing of peptic ulcer and erosive oesophagitis and control of acid-related symptoms. The suppression of gastric acid secretion achieved with H(2)-receptor antagonists has, however, proved to be suboptimal for effectively controlling acid-related disorders, especially for healing erosive oesophagitis and for the relief of reflux symptoms. H(2)-receptor antagonists are also not effective in inhibiting meal-stimulated acid secretion, which is required for managing patients with erosive oesophagitis. Furthermore, the rapid development of tolerance to H(2)-receptor antagonists and the rebound acid hypersecretion after the withdrawal of an H(2)-receptor antagonist further limit their clinical use. Although low-dose H(2)-receptor antagonists are currently available as over-the-counter medications for self-controlling acid-related symptoms, their pharmacology and pharmacodynamics have not been well studied, especially in the self-medicating population. Proton pump inhibitors have been proved to be very effective for suppressing intragastric acidity to all known stimuli, although variations exist in the rapidity of onset of action and the potency of acid inhibition after oral administration at the approved therapeutic doses, which may have important clinical implications for the treatment of gastro-oesophageal reflux disease and perhaps for eradicating H. pylori infection when a proton pump inhibitor is given with antibiotics. Once-daily dosing in the morning is more effective than dosing in the evening for all proton pump inhibitors with respect to the suppression of intragastric acidity and daytime gastric acid secretion in particular, which may result from a better bio-availability being achieved with the morning dose. When higher doses are needed, these drugs must be given twice daily to achieve the optimal suppression of 24 hour intragastric acidity. Preliminary results have shown that esomeprazole, the optical isomer of omeprazole, given at 40 mg, is significantly more effective than omeprazole 40 mg, lansoprazole 30 mg or pantoprazole 40 mg for suppressing gastric acid secretion. However, more studies in different patient populations are needed to compare esomeprazole with the existing proton pump inhibitors with regard to their efficacy, cost-effectiveness and long-term safety for the management of acid-related disorders.

Drug utilization evaluation of nonprescription H2-receptor antagonists and alginate-containing preparations for dyspepsia

AIMS

To evaluate the use, efficacy and adverse effects of nonprescription H2-receptor antagonists and alginate-containing preparations obtained from community pharmacies.

METHODS

Questionnaires were distributed to customers from 39 pharmacies in Scotland and Wales.

RESULTS

Of 767 customers recruited, 608 (79.3%) returned an initial questionnaire and 472 (61.5%) customers a second questionnaire. The vast majority of respondents (424, 69.7%) had suffered their symptoms on three or more occasions and 369 (60.7%) had previously tried medicines to relieve their symptoms. Referrals to a doctor were less frequent than recommended in guidelines and few of those who were referred actually saw a doctor. Over a quarter of those returning the second questionnaire claimed to be taking more than one product simultaneously for symptom control. Eight customers who were taking prescribed ulcer-healing drugs obtained H2-receptor antagonists. The majority of respondents (355/472, 75. 2%) obtained some or complete symptom relief using the product obtained and 369/472 (78.2%) were completely satisfied with their product. H2-receptor antagonists were more likely to produce complete relief of symptoms than alginate-containing preparations (P < 0.05). Only 14 respondents (3.0%) reported side-effects from the product used which were mostly gastro-intestinal.

CONCLUSIONS

The study demonstrated that drug utilization studies are feasible to carry out in a community pharmacy setting. While the results support published evidence of the efficacy and minimal toxicity of these products, they also highlight the possibility of H2-receptor antagonists being used outwith their licenced indications.

Impact of food intake on the antisecretory effect of low-dose ranitidine and famotidine

BACKGROUND

Over-the-counter status has recently been approved for low-dose H2-antagonists in several countries. Insufficient information is currently available on the effect of food in low-dose H2-antagonist therapy.

AIM

Compare the antisecretory efficacy of low-dose ranitidine and famotidine in fasting and non-fasting volunteers.

METHODS

Twenty volunteers were randomized into a double-blind, placebo-controlled, multiple-step crossover study comparing the antisecretory efficacy of 75 mg ranitidine, 10 mg famotidine and placebo over 12 h using intragastric pH-metry. Two standard meals were given after 4 h and 8 h of medication. Fifteen volunteers also participated in a second study comparing the antisecretory effect of both drugs, both with and without meals.

RESULTS

In non-fasting subjects, the percentage of time with pH > 4 was similarly elevated for both drugs compared with placebo over the first 8 h: ranitidine 39.3%, famotidine 29.5%, placebo 9.5% (P < 0. 001); but not for the last 4 h after the second meal (P > 0.05). Comparing the first 4-h period with the second, the percentage of pH > 4 was significantly reduced for both drugs in the second period in the subjects given food at the end of the initial 4-h period (ranitidine 56.9% vs. 26.6%, P = 0.005; famotidine 46.6% vs. 13.3%, P < 0.001). It remained more or less constant, however, for the second 4-h period in fasting subjects (ranitidine 41% vs. 28.1%, P = 0.46; famotidine 52.7% vs. 52.2%, P = 0.12).

CONCLUSION

In non-fasting volunteers both low-dose H2-antagonists had comparable antisecretory effects and were superior to placebo over the first 8 h of therapy. Both drugs achieved a slightly higher antisecretory effect without food intake compared to with food intake.

Effects of tablet and effervescent formulations of ranitidine 75 mg and cimetidine 200 mg on gastric acidity and oesophageal acid exposure in healthy humans

BACKGROUND

Because of their tolerance and safety, low doses of H2-receptor antagonists are now increasingly used in some countries for self-care medication of gastro-oesophageal reflux symptoms.

AIM

The purpose of this randomized, double-blind, placebo-controlled, five-way crossover study was to determine and to compare the effects of low doses of ranitidine and cimetidine both on gastric pH and on oesophageal acid exposure.

METHODS

Gastric and oesophageal pH were simultaneously monitored in 20 healthy subjects using two glass pH electrodes, after placebo and single doses of ranitidine 75 mg and cimetidine 200 mg (effervescent and tablet forms), for 4 h before and after a meal.

RESULTS

During the fasting period, median gastric pH rose significantly with both drugs, but more rapidly with the effervescent forms; the oesophageal acid exposure was significantly decreased by all drug regimens. After the meal, although there was no significant difference in gastric pH values, oesophageal acid exposure was significantly decreased in comparison with placebo with both forms of ranitidine (P < 0.05), and also for ranitidine tablets in comparison with cimetidine tablets (P < 0.05).

CONCLUSIONS

Low doses of ranitidine and cimetidine increase gastric pH, with a more pronounced effect for ranitidine. Effervescent formulations of both drugs induce a slightly more rapid initial increase in pH than tablets. Ranitidine demonstrates a more prolonged effect than cimetidine and decreases oesophageal acid exposure monitored after a meal ingested 4 h after the drug intake.