GI Pharmacology Flashcards
What are some ways for managing peptic ulcer with drugs
Reducing gastric acid secretion
Neutralizing secreted gastric acid
Increase mucosal resistance to acid-pepsin attacks
Eradicating H. pylori
What classes of drugs could help in reducing gastric acid secretion
H2-receptor antagonists
Proton pump inhibitors and
Muscarinic receptor antagonists
What class of drug could be used to neutralize secreted gastric acid
Antacids
Which class of drugs could be used to Increase mucosal resistance to acid-pepsin attacks
Misoprostol or chelates
What is the MOA of histamine H2 receptor antagonists
Competitive blockade of histamine on the H2 receptor
What are some examples of histamine H2 receptor antagonist drugs
Cimetidine and ranitidine
What are some indications for histamine H2 receptor antagonists
Peptic ulcer and GORD
What are some contraindications for cimetidine
Cimetidine not given to patients stabilized on warfarin, phenytoin, and theophylline
What are some adverse effects of histamine H2 receptor antagonists
Dizziness
Fatigue
Rashes
Low sperm count due to antiandrogenic effects
What are some examples of PPIs
Omeprazole, Esomeprazole
What is the MOA of PPIs
Irreversible inhibition of H+/K+ ATPase responsible for proton secretion from parietal cells. They are pro-drugs, converted at acid pH to sulphonamide, which combines covalently with sulphydryl groups on the H+/K+ ATPase
What are some indications of PPI
Short-term treatment of peptic ulcers, eradication of H. pylori, oesophagitis, Zollinger-Ellison syndrome
What are some adverse effects of PPIs
GI upsets, nausea, headaches, gastric atrophy with long term treatment
What are some examples of muscarinic receptor antagonists
Atropine
Pirenzepine
Dicyclomine (dicycloverine)
What is the MOA of muscarinic receptor antagonists
Inhibition of parasympathetic activity, causing relaxation of GI smooth muscle as well. They may be of value in peptic ulcer since the condition may be accompanied by increased muscle spasm
What are the indications of muscarinic receptor antagonists
As adjuncts in the management of peptic ulcer
What is an example of a mucosal strengthener drug
Misoprostol
What is the MOA of mucosal strengtheners
Synthetic analogue of PG E, imitating the action of endogenous PGE2 and PGI2, thereby maintaining the
integrity of the gastroduodenal barrier. It therefore promotes healing
What are some indications for given mucosal strengtheners
Ulcer healing and prophylaxis with NSAID use
What are some contraindications of mucosal strengtheners
Hypotension, pregnant and
breast-feeding women
What are some adverse effects of mucosal strengtheners
Diarrhoea, nausea and abdominal pain
What are some examples of chelates
Bismuth chelate and sucralfate
How do chelates protect the mucosa
Inhibiting the action of pepsin
Promoting the synthesis of protective prostaglandins
Stimulating the secretion of bicarbonate
They are given orally and well tolerated
Give some examples of neutralizing secreted acid with antacids
Aluminium hydroxide, magnesium hydroxide and sodium bicarbonate