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Immunosuppressants, rheumatic and gastrointestinal topics
Published in Evelyne Jacqz-Aigrain, Imti Choonara, Paediatric Clinical Pharmacology, 2021
Evelyne Jacqz-Aigrain, Imti Choonara
The pharmacokinetic profiles of PPIs are similar to those in adults but there is significant interindividual variability Dosage should be reduced in infants less than 3 months and neonates. Doses used are 2 to 3.5 mg/kg/d with omeprazole and 1.5 mg/kg/d with lansoprazole [16,17]. Most PPIs are metabolised by a genetically polymorphic enzyme, CYP2C19, that is absent in approximately 20% of Asians and 3% of Caucasians [18]. Side effects are reported in 10% of cases: headache, dizziness, constipation, diarrhoea, cutaneous reactions, gynaecomastia and proliferation of gastric flora. Hypergastrinemia occurs in all patients on long term PPI. Theoretically, this could lead to gastric malignancy, but fortunately this never has been observed!
Postulated Physiological and Pathophysiological Roles on Motility
Published in Edwin E. Daniel, Neuropeptide Function in the Gastrointestinal Tract, 2019
Hans-Dieter Allescher, Sultan Ahmad
Gastrin is a potent stimulator of gastric acid secretion. Its role in the regulation of gastrointestinal motility is far less characterized. Excessive secretion of gastrin can be observed due to a gastrinoma, a gastrin-producing tumor, or as a consequence of reduced acid secretion caused by Billroth II surgery, atrophic gastritis, or drugs (H2 blockers or omeprazol). No specific motility changes in these hypergastrinemia conditions have been reported, and the diarrhea observed in gastrinoma patients probably is primarily due to the changes in the secretory responses and, to a minor extent, to motility changes. The possible physiological role in the regulation of antral motility and in the maintenance of the basal lower esophageal sphincter pressure awaits further confirmation with new selective gastrin receptor antagonists.
Gastrinoma (Zollinger–Ellison syndrome) and rare neuroendocrine tumors
Published in Demetrius Pertsemlidis, William B. Inabnet III, Michel Gagner, Endocrine Surgery, 2017
In order to interpret the hypergastrinemia, it is essential to know whether the elevated gastrin is due to a physiological response to decreased gastric acid secretion, as in pernicious anemia. Gastric acid production may be assessed by measurement of nasogastric (NG) tube aspirate pH or, less readily available, measurement of basal acid output (BAO) (mmol/h). Either a pH of ≤2 or a BAO of >15 mmol/h is suggestive of ZES if hypergastrinemia is also present [41]. Elevated gastrin may also be associated with gastric acid hypersecretion in other conditions, such as retained excluded antrum, or associated with achlorhydria or hypochlorhydia in patients with atrophic gastritis or pernicious anemia. The patient history, gastric pH, and secretin stimulation test will aid in making the correct diagnosis.
Gastric lesions in patients with autoimmune metaplastic atrophic gastritis: a retrospective study in a single center
Published in Scandinavian Journal of Gastroenterology, 2022
Haiyi Hu, Rongxue Li, Linlin Shao, Qian Zhang, Rui Xu, Shutian Zhang
All patients had blood taken to measure their fasting serum gastrin-17 concentration (35–100 pg/ml, ELISA), serum PGI/II ratio (immunoassay), hemoglobin (male 120–160 g/l, female 110–150 g/l), serum vitamin B12 (abnormal < 190 pg/ml), serum iron (7.8–32.2 umol/l), serum ferritin (11.0–306.0 ng/ml), serum anti-parietal cell antibody (PCA, abnormal >1:80, IIFA), serum anti-intrinsic factor antibody (IF, abnormal >1:20, ELISA), serum thyroid function tests (TFTs) and Helicobacter pylori serology. H. pylori status was determined by serum H. pylori IgG and 13C-urea breath test (UBT) or by histological evaluation of gastric biopsies. H. pylori negative patients did not receive any eradication therapy or proton pump inhibitor/H2 receptor antagonist before the test. Hypergastrinemia was diagnosed when the fasting serum gastrin concentration was two times higher than the upper limit of the normal range.
Pharmacokinetics of single and repeated oral doses of esomeprazole and gastrin elevation in healthy males and females
Published in Scandinavian Journal of Gastroenterology, 2021
Hólmfríður Helgadóttir, Sigrún H. Lund, Sveinbjörn Gizurarson, Helge Waldum, Einar S. Björnsson
The gastrin concentration levels are shown in Table 2. Female participants had significantly higher baseline gastrin levels than males. Median fasting serum gastrin levels increased by approximately 50% during the treatment (p=.00015). The increase in gastrin was significant in both sexes, from a mean of 12.4–16.4 pM in females (p =.0017) and of 8.5–17.4 pM in males (p =.0058) (Figure 2). Despite the above described findings, there was not a significant difference between the sexes at the end of treatment (p =.89). Although the change in gastrin level from baseline was higher among males, mean 8.9 pM (105%), than females, mean 4 pM (32%), this difference did not reach a statistical significance (p =.11). Only one participant (male) had hypergastrinemia after four days of PPI therapy, with a value of 45 pM.
Gastric cancer and gastrin: on the interaction of Helicobacter pylori gastritis and acid inhibitory induced hypergastrinemia
Published in Scandinavian Journal of Gastroenterology, 2019
Helge L. Waldum, Jens F. Rehfeld
Hypergastrinemia is a central mechanism for development of gastric cancer. Hormones may so far have been underestimated in carcinogenesis. The knowledge of the important role of hormones in tumorigenesis opens new possibilities for prevention of tumors but should also result in caution in inducing long-term hormonal overstimulation. In fact, the pathogenetic role of gastrin in gastric carcinogenesis can explain all the clinical experiences: (1) the central role of oxyntic atrophy with only a limited role of intestinal metaplasia, (2) the curative effect of Helicobacter pylori eradication on gastric lymphoma but often not on gastric cancer and, (3) the gastric carcinogenic effect by PPIs in previously Helicobacter pylori infected individuals.