文档介绍：Dyspepsia, Peptic Ulcer Disease and Helicobacter Pylori
Pharmacology & Therapeutics February 2007
Dyspepsia
40% of all adults
4% GP consultations
10% further investigations
10-20% NSAID users
Endoscopy findings
15% Duodenal or Gastric ulcer
15% Oesophagitis = GORD
30% Gastritis duodenitis or hiatus hernia
30% Normal = functional dyspepsia
Pathogenesis of Dyspepsia
Factor
Treatment approach
Infection with H. pylori
Eradication of H. pylori infection, . triple tx
↑ gastric HCl secretion
↓ HCl secretion or neutralizing it, . H2 antagonists, pirenzepine, antacids , PPIs
Inadequate mucosal defence against gastric HCl
Agents that protect gastric mucosa, . sucralfate
Altered gastric motility
ic agents eg metoclopramide
Gastric acid secretion
Helicobacter Pylori
Antacids
MOA: Weak bases that react with gastric acid to form H20+salt. ↓pepsin activity as pepsin inactive at pH>4
Symptom relief, liquids>tablets
. Maalox = Mg(OH)2 + Al(OH)3
Drug
Side effect
Magnesium
severe osmotic diarrhoea (bined with AlOH)
↓ drug absorption
Aluminium
↓phosphate, ↓absorption of tetracycline, thyroxine & chlorpromazine, constipation
Calcium
↑Ca in blood & urine (high doses)
Mucosal Protective Agents
1) Sulcralfate
MOA: Binds to positively charged proteins present on damaged mucosa forming a protective coat
Useful in “stress ulceration”
As effective as H2-R antagonists/high dose antacids
SE: Constipation
↓absorption of cimetidine, digoxin, phenytoin & tetracycline
2) Bismuth
MOA: Antimicrobial action. Also inhibit pepsin activity, ↑mucus secretion & interact with proteins in necrotic mucosal tissue to coat & protect the ulcer crater
Additional agents
Antifoaming agent
– Dimethicone to relieve flatulence (surfactant)
Alginates
- form a raft on surface of stomach contents to reduce reflux
Carbenoxolone
- liquorice derivative ? Alters mucin s/e H2O retention ↓K+