Omeprazole treatment of severe peptic disease associated with antral G cell hyperfunction and hyperpepsinogenemia I in an infant

Exploiting drug delivery systems for oral route in the peptic ulcer disease treatment

Peptic ulcer disease (PUD) is a common condition that is induced by acid and pepsin causing lesions in the mucosa of the duodenum and stomach. The pathogenesis of PUD is a many-sided scenario, which involves an imbalance between protective factors, such as prostaglandins, blood flow, and cell renewal, and aggressive ones, like alcohol abuse, smoking, Helicobacter pylori colonisation, and the use of non-steroidal anti-inflammatory drugs. The standard oral treatment is well established; however, several problems can decrease the success of this therapy, such as drug degradation in the gastric environment, low oral bioavailability, and lack of vectorisation to the target site. In this way, the use of strategies to improve the effectiveness of these conventional drugs becomes interesting. Currently, the use of drug delivery systems is being explored as an option to improve the drug therapy limitations, such as antimicrobial resistance, low bioavailability, molecule degradation in an acid environment, and low concentration of the drug at the site of action. This article provides a review of oral drug delivery systems looking for improving the treatment of PUD.

Intravenous omeprazole in children: pharmacokinetics and effect on 24-hour intragastric pH

BACKGROUND

Omeprazole is a proton pump inhibitor, acting selectively on the gastric parietal cell H+K+-adenosine triphosphatase. Data on the intravenous route are limited in children and not available in infants.

OBJECTIVE

This study was designed to determine the pharmacokinetics and the optimal dosage of intravenous omeprazole in patients younger than 30 months of age.

METHODS

Nine children (three girls), aged 4.5 to 27 months, with normal liver and renal functions requiring intravenous omeprazole were studied. After enrollment in the study and randomization, omeprazole was administered once daily, at 8 am, as a 1-hour infusion. Group 1, consisting of the first four patients, received 20 mg/1.73 m2, and group 2, consisting of the following five patients, received 40 mg/1.73 m2. At day 3, a 24-hour intragastric pH and a pharmacokinetic study of omeprazole were performed. Plasma concentrations were measured by high-performance liquid chromatography.

RESULTS

Patients in group 2 had a significantly higher median pH (6.99 vs. 3.35; P = 0.01) and percent of monitored time with gastric pH >4 than children given 20 mg/1.73 m2 (90.6% vs. 44.8%; P < 0.01). Four had a pH more than 4 during more than 90% of the time versus none of the patients of group 1. The plasma concentration versus time curves showed rapid elimination of the drug. The median area under the curve of omeprazole was 0.78 microg. mL-1. h-1 (range, 0.55-1.64 microg. mL-1. h-1) and 3.95 microg. mL-1. h-1 (range, 1.9-4.9 microg. mL-1. h-1), respectively, in groups 1 and 2 (P < 0.05). Systemic clearance was not different between the two groups: median values were 0.68 and 0.42 L. kg-1. h-1 (P = 0.22).

CONCLUSIONS

In critical situations, intravenous administration of omeprazole may be required in infants. The authors demonstrate that the dose of 20 mg/1.73 m2 is not effective in maintaining 24-hour gastric pH of more than 4 and that a dose of 40 mg/1.73 m2 is required.

Peptic ulcer disease in children

A peptic ulcer in a child looks the same as it does in an adult, and many of the aetiologies of peptic ulcer disease in children are similar to those in adults. However, there are many differences between children and adults, especially in the areas of clinical presentation, the prevalences of different types of ulcer disease, and the prevalence of complications of ulcer disease. Therefore the approach to diagnosis and management in children is often at variance with that in adults. One important example is the approach to suspected Helicobacter pylori (H. pylori) disease in children, in which consensus groups have advised a considerably different approach in children. While the chapter deals with the full range of peptic ulcer disease in children, the focus is on those aspects in which there are differences between adults and children.

Upper gastrointestinal tract bleeding in critically ill pediatric patients

Similar to adults, children under physiologic stress can develop an imbalance in defensive (mucosal layer, motility) and aggressive (gastric acid, bile salts, enzymes) factors responsible for maintaining a healthy gastrointestinal tract. Hypoxia in the gastrointestinal tract likely disrupts the defensive factors, thereby permitting damage by aggressive factors to upper gastrointestinal epithelium that may progress to stress ulceration and acute upper gastrointestinal tract bleeding (UGIB). The basic pathophysiology may be similar in children and adults; however, differences in the time to developing ulceration, ulcer location, and number of ulcers have been reported. Functional development of the gastrointestinal tract is influenced by disease, gestational and postnatal age, and exposure to and type of enteral feedings, thereby confounding the development and prophylaxis of UGIB in neonates and infants. In addition, pharmacotherapy decisions are often complicated by drug administration issues and adverse effects.

Omeprazole for severe reflux esophagitis in children

BACKGROUND

Severe esophagitis is a rare complication of gastroesophageal reflux in children. In adults, omeprazole therapy of severe erosive esophagitis has become the gold standard short-term treatment of the disease. In children, data on its use are limited, and problems about the dosage are unresolved. The aim of this study was to evaluate the efficacy of a simplified, body-weight-based daily dosage of omeprazole in children with severe esophagitis.

METHODS

Ten children (median age 75.6 months; range 25-109 months) with severe esophagitis were prospectively investigated. All patients were evaluated by endoscopy, histology, and 24-h pH-metry study before and after 3 months of omeprazole. The starting dose of omeprazole was 20 mg as a single daily dose in children weighing less than 30 kg, and 40 mg daily for those weighing over 30 kg.

RESULTS

A significant improvement in all the children was demonstrated after 3 months of treatment by clinical, endoscopic, and pH-metry assessment. However, histologic study failed to show significant improvement of both inflammatory and hyperplastic findings. Relapse occurred in six of 10 patients after discontinuation of therapy.

CONCLUSIONS

Omeprazole is effective in the short-term treatment of severe oesophagitis in children. The daily dose of the drug could be easily based on the body weight. The persistence of histologic features of esophagitis in spite of clinical and endoscopic healing could be an indicator of poor outcome.

Effect of omeprazole in the treatment of refractory acid-related diseases in childhood: endoscopic healing and twenty-four-hour intragastric acidity

OBJECTIVE

To determine the clinical efficacy of once-daily treatment with omeprazole in refractory acid-related diseases in children.

METHODS

Endoscopic healing and 24-hour intragastric pH values were assessed in 13 patients with refractory reflux esophagitis (n = 5), refractory and/or giant duodenal ulcer (n = 6), or giant gastric ulcer (n = 2). The mean dose of omeprazole was 0.6 mg/kg per day (range, 0.3 to 0.7 mg/kg per day). Pharmacokinetic studies of omeprazole were performed in seven patients.

RESULTS

The cumulative healing rates at 2, 4, 6, and 8 weeks of treatment were 46%, 85%, 92%, and 92%, respectively. Esophagitis in one patient did not heal despite increases in doses of up to 1.6 mg/kg per day (40 mg/day). The mean intragastric pH of omeprazole-treated patients was 5.2 (range, 3.0 to 6.6) and mean hydrogenion activity was 1.78 mmol/L (range, 0.01 to 10.42 mmol/L). There was wide interindividual variation in the reduction of gastric acid production. Mean intragastric H+ activity in omeprazole-treated patients was significantly lower than that of control subjects (p < 0.005) and that of patients treated with histamine type 2(H2)-receptor antagonists (p < 0.05). Mean intragastric H+ activity was not significantly correlated to the area under the concentration-time curve of omeprazole. No severe adverse effects were reported during treatment or at follow-up.

CONCLUSIONS

Omeprazole has a potent antisecretory effect and is a suitable alternative for short-term treatment of refractory acid-related diseases; a relatively low dose (0.6 mg/kg per day) appears to be optimal in most patients. Unhealed esophagitis at 8 weeks of treatment was considered to be refractory to omeprazole.

The effect of omeprazole on human natural killer cell activity

1. Omeprazole, an antiulcer drug, inhibits the gastric acid pump via blocking the parietal cell (H+ + K+)-ATPase. Omeprazole was also reported to have an inhibitory action on polymorphonuclear neutrophil activities. In the present study the potential effect of omeprazole on human natural killer cell (NK) activity was investigated. 2. Omeprazole decreased NK cytotoxic activity in a dose-dependent manner. 3. Degraded omeprazole showed a similar action. 4. In vitro NK inhibitory action of omeprazole and its acid-degraded form was observed at the concentrations equal and higher than 18 microM (micromolar). 5. NK inhibitory action of omeprazole was recovered to 75% by washing away of the agent. 6. Omeprazole decreased the conjugate formation of effector and target cells by 50% at the concentration of 288 microM

Omeprazole reduces preoperative gastric fluid acidity and volume in children

To explore the effects of oral omeprazole on preoperative gastric fluid pH and volume in children, 104 healthy in-patients aged 4-9 yr were randomly allocated to four groups (n = 26). Subjects in the Omeprazole-Omeprazole Group received two doses of omeprazole (20 mg per dose), those in the Placebo-Placebo Group, two doses of placebo, those in the Placebo-Omeprazole and Omeprazole-Placebo Groups, one dose each of the two preparations by mouth. For each treatment regimen, the first medication was administered at 9:00 p.m. on the night before surgery and the second at 5:30 a.m. on the morning of the day of surgery (three hours preoperatively). Children undergoing elective surgery were offered 10 ml.kg-1 of apple juice three hours before induction of anaesthesia. After induction of anaesthesia and tracheal intubation, gastric fluid was aspirated through a large-bore, multiorifice orogastric tube and analyzed for pH and total fluid volume. The administration of omeprazole at bedtime before surgery increased gastric pH (3.3 +/- 1.3 vs 2.0 +/- 0.6, P < 0.05) in comparison with placebo, as did two doses of omeprazole (pH = 4.8 +/- 1.6, P < 0.05). A single dose of omeprazole administration on the morning of the day of surgery failed to increase gastric pH. There was a reduction in the number of children with a pH < 2.5 and a volume > 0.4 ml.kg-1 in the Omeprazole-Omeprazole and Omeprazole-Placebo Groups, compared with the Placebo-Placebo or Placebo-Omeprazole Groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Pharmacokinetics of intravenous omeprazole in children

This study was undertaken to define the pharmacokinetics of omeprazole in children and included 13 patients, heterogeneous in terms of age (0.3 to 19 years), underlying disease and biological constants, indication of omeprazole administration and associated therapy. The dose administered ranged from 36.9 to 139 mg.1.73 m-2. The pharmacokinetic parameters of omeprazole were: systemic clearance, 0.23 l.kg-1.h-1; volume of distribution, 0.45 l.kg-1; elimination half life 0.86 h; but were highly variable between individuals. Dosage, differences in hepatic and renal function and associated therapy may contribute to inter-individual variability. Within the range of doses administered, the pharmacokinetic parameters were similar to those reported in adults. The drug has been well tolerated in all children.

Efficacy and safety of omeprazole for severe gastroesophageal reflux in children

Omeprazole, a potent inhibitor of acid secretion, is effective in adults with severe gastroesophageal reflux, but no such data are available on children. We studied 15 children in whom treatment with histamine (type 2) blockers and prokinetic agents had failed; 4 had also had one or more fundoplications. Their ages were 0.8 to 17 years (mean, 8.1 years) and weights were 7.5 to 30.7 kg (mean, 18.6 kg). Of the 15 children, 8 were neurologically handicapped. All patients had endoscopic and histologic evidence of esophagitis; most had esophagitis grade 3 to 4. Patients were initially given omeprazole at 10 to 20 mg; the dose was titrated upward until results of a subsequent 24-hour intraesophageal pH study was normal. Symptoms and signs abated and evidence of esophagitis diminished in all patients. Omeprazole was given for periods of 5.5 to 26 months (mean, 12.2 months). The effective total dose was 20 to 40 mg (0.7 to 3.3 mg/kg) in 11 patients, 10 mg (0.7 mg/kg) in 1 patient, and 60 mg (1.9 to 2.4 mg/kg) in 3 patients. The dosage range was 0.7 to 3.3 to mg/kg per day (mean, 1.9 mg/kg). Mildly elevated transaminase values in 7 patients and elevated fasting gastrin levels in 11 patients were present; in 6 of the 11, gastrin levels were 3 to 5.5 times the upper limit of normal. We found omeprazole to be highly effective in this group of patients with severe esophagitis refractory to other measures. We recommend a starting dose of 0.7 mg/kg as a single morning dose; the adequacy of reflux control is then determined by follow-up 24-hour intraesophageal pH studies. Omeprazole appears to be safe for short-term use, but further studies are needed to assess long-term safety because the significance of chronically elevated gastrin levels in children is unknown.

Antral gastrin cell hyperfunction in children. A functional and immunocytochemical report

Antral gastrin cell hyperfunction is a rare condition, often associated with severe duodenal ulcer disease. In children, clinical and functional characteristics of this syndrome are poorly known. Two cases are described here: one child had melena and the other had moderate abdominal pain, both without peptic ulceration. Basal and postprandial increase of gastrin levels showed a response over the upper normal range, indicating gastrin cell hyperfunction. Acid hypersecretion, both basal and after pentagastrin stimulation, was also found in the two children, confirming the biological effect of their sustained hypergastrinemia. Gastrin cell counts were within the normal range, while the number of somatostatin D cells was significantly reduced. This report stresses the importance of diagnosing antral gastrin cell hyperfunction in children because this unrecognized condition may manifest with serious complications (bleeding) or nonspecific abdominal symptoms.