Lec1 - Peptic Ulcer Flashcards
(14 cards)
Define peptic ulcer and what are the clinical features of it?
It is occur when there is an imbalance between damaging effects of gastric acid, pepsin, and the defence mechanisms, which protect the gastric and duodenal mucosa from these substance
Clinical feature of ulcer: Is a chronic condition, the common presentation is :
recurrent abdominal pain which has three notable characteristics:
localization to epigastrium
relation to food
episodic occurrence.
- Occasional vomiting occurs in about 40% of ulcer subjects
Mechanisms of action pf peptic ulcer : possibly MCQ
Gastric acid secretion by parietal cells of gastric mucosa is stimulated by acetylcholine, histamine, and gastrin.
The receptor mediated binding of
acetylcholine, histamine or gastrin results in the activation of proteinkinase, which in turn stimulates the H / K –adinosine triphosphatase (ATPase) proton pump to secret hydrogen ions in exchange for K into lumen of the stomach leading to secretion of acid.
- acetylcholine (through Na+ and IP3 (inositol triphosphate),
*histamine (Histamine by stimulating H2 receptors ends up by
adenylate cyclase mechanism) - gastrin (through Na+)
(*) In contrast receptor binding of prostaglandin E2 and somatostatin leads to diminish gastric acid production.
drugs can alter the balance towards healing and prevention of recurrence of ulcer by the general ways, mention it
1- general, including :
- Rest: help in healing gastric and duodenal ulcer.
- Diet: Decrease spices, regular frequent light meals.
- Hygiene: stop smoking, alcohol, caffeine, NSAIDs.
drugs can alter the balance towards healing and prevention of recurrence of ulcer by the drugs, mention it ? Possibly MCQ
- Reduction of acid secretion by:
a. Histamine H2 receptoantagonists e.g.: cimetidine, ranitidine, nizatidine, and famotidine.
b. Proton pump inhibitors (PPI) e.g.: omeprazole, dexlansoprazole, lansoprazole, pantoprazole, rabeprazole, and esomeprazole.
c. Antimuscarinic drugs: e.g.: pirenzepine, dicyclomine and telenzepine.
d. Synthetic somatostatin analog: As octreotride.
- Neutralization of secreted acid by antacids e.g.: magnesium trisilicate, aluminum hydroxide, etc.
- Antigastrin agents: a. proglumide. b- oxethazaine.
- Enhancement of mucosal resistance by
a. Protecting the base of peptic ulcer e.g.: bismuth chelate, sucralfate, carbenoxolone.
b. Cytoprotection (misoprostol) a PGE1 analog. - Eradication helicobacter pylori (H. pylori) infection.
MCQ
1- according to the drugs of Reduction of acid secretion by Histamine H2 receptor antagonists is (except)
2- according to the drugs of Reduction of acid secretion by Proton pump inhibitors (PPI) is (except) :
3- according to the drugs of Reduction of acid secretion by Antimuscarinic drugs is (except)
4- according to the drugs of Reduction of acid secretion by Synthetic somatostatin analog all the follwoind is false (except)
5- to healing and prevention of recurrence of ulcer by Neutralization of secreted acid by
6- to healing and prevention of recurrence of ulcer by Antigastrin agents:
7- to healing and prevention of recurrence of ulcer by Enhancement of mucosal resistance by
1- cimetidine
pirenzepine
ranitidine
nizatidine, and famotidine
2-omeprazole
cimetidine
dexlansoprazole
lansoprazole
pantoprazole
rabeprazole and esomeprazole.
3- pirenzepine
dicyclomine and telenzepine.
dexlansoprazole and ranitidine
4- octreotride.
dicyclomine
lansoprazole
pantoprazole
pirenzepine
5- antacids e.g.: magnesium trisilicate, aluminum hydroxide, etc.
6- proglumide.
oxethazaine
7- a. Protecting the base of peptic ulcer e.g.:
bismuth chelate
sucralfate
carbenoxolone
b. Cytoprotection (misoprostol) a PGE1 analog.
- Eradication helicobacter pylori (H. pylori) infection to healing and prevention of recurrence of ulcer
Pharmacokinetics: possibly T/F or MCQ
1- All of them are well absorbed after oral dose.
2- Antacids decreases their absorption in about 10-20%.
3- They are distributed widely throughout the body (including into breast milk and across the placenta) and are excreted mainly in urine.
4- Bioavailability of cimetidine, ranitidine, and famotidine is decreased by 30-50% by 1st pass metabolism
5- nizatidine has little 1st pass metabolism, bioavailability of nizatidine is 90-100%
6- Efficacy is the same for all, but potency differs (differs are used)
7-(Cimetidine) is a well known inhibitor of hepatic digesting oxidizing enzyme system P450, so it leads to increase plasma level of many drugs like: warfarin, cyclosporine, Ca+ channel blockers, propranolol, theophylline, diazepam, sulfonyl ureas, TAD, and antiarrhythmic like quinidine, mexiletine, phenytoin, and lignocaine.
8- Ranitidine is 5-10% more potent than cimetidine and longer duration acting (t1/2=2hrs., 50% metabolized). it requires a less frequent dosing schedule, twice daily (b.i.d.). Ranitidine does not bind to the androgen receptor. It does not inhibit hepatic microsomal enzyme.
9- Ranitidine has minimal side effects.
10-Famotidine is 20-50 time more potent than cimetidine. 3-20 times more potent than ranitidine and similar to ranitidine in pharmacological action and has a longer duration of action; it is given once daily. Famotidine is no inhibit hepatic microsomal enzyme.
11-Nizatidine is similar to ranitidine in pharmacological action and potency (effective). Its bioavailability is nearly 90-100% and may be administrated once daily and eliminated principally by the kidney.
12- Nizatidine may produce hepatotoxicity.
13 -The dosage of these drugs must be decreased with hepatic or renal failure.
All of above is True
What are the therapeutic uses of H2- receptor antagonists ?
- Peptic ulcers and non-ulcer dyspepsia.
- Acute stress ulcers and prevention of bleeding from stress related gastritis by giving IV infusion.
- GERD (gastroesophageal reflux disorder) at low dose in only 50% of patients for the prevention and treatment of heartburn.
- Healing of NSAID ulcers if the NSAID is discontinued.
5- before anaesthesia for emergency surgery and before labour to lessen the risk of pulmonary aspiration of gastric acid.
What are side effects of H2 recpeter antagonists ?
1- They are few in short term use. The most side effects include headache, dizziness, diarrhea, tiredness, and muscular pain.
2- Bradycardia and cardiac conduction defects may occur after I.V. injection of cimetidine.
3- Cimetidine has weak anti-androgenic effect and it increase prolactin secretion leading to gynecomastia, galactorrhea and sexual dysfunction in males, other H2 antagonists have no anti-androgenic effects.
4-In elderly, and after intravenous administration H2 receptor antagonists may cause CNS disturbances including lethargy, confusion, and hallucination
mechanisms of Actions of histamine H2 receptor antagonists
The histamine H2 receptor antagonists act selectively on H2 receptors in the stomach, without effects on H1 receptors.
They are competitive antagonists of histamine and are fully reversible
Side effect of histamine H2 receptor (Reduction of acid secretion) is :
1- They are few in short term use. The most side effects include headache, dizziness, diarrhea, tiredness, and muscle pain
2- Bradycardia and cardiac conduction defects may occur after I.V. injection of cimetidine (possibly MCQ)
3- Cimetidine has weak anti-androgenic effect and it increase prolactin secretion leading to gynecomastia, galactorrhea and sexual dysfunction in males, other H2 antagonists have no anti-androgenic effects.
4- In elderly, and after intravenous administration H2 receptor antagonists may cause CNS disturbances including lethargy, confusion, and hallucination
Treatment Course:
This course continues for duodenal ulcer 4-6 weeks and for gastric ulcer 6-8 weeks.
Therapeutic uses of PPIs ?
1-. Prefer drugs for stress ulcer treatment and prophylaxis.
2- Erosive esophagitis.
Active duodenal and benign gastric ulcer.
They are drugs of choice for hypersecretory condition as Zollinger-Ellison syndrome for long term treatment.
3- For GERD better than H2-blockers (twice daily or PPIs in morning and H2 antagonist in evening.
4- They are drugs of choice for ulcers produced by NSAID, they can produce healing in spite of continuation of the NSAIDs.
5- Reduce the risk of bleeding from an ulcer caused by aspirin and other NSAIDs.
6- Successfully used with antimicrobial regimens to eradicate H. pylori
Side effects of PPIs :
1- Nausea, vomiting, headache, diarrhea.
2- Bone fracture (increased risk with long term use one year or greater, hip, wrist and spine).
3- PPIs may impair the absorption of vitamin B12, calcium, zinc, and iron.
4- Omeprazole inhibits metabolism of warfarin, phenytoin and diazepam but much less than cimetidine.
5- Omperazole decreases the effect of the clopidogrel drug
Synthetic somatostatin analogue is : possibly MCQ
As octreotride, it is long acting, it has been found to inhibit the secretion of several circulating peptyide hormones and to inhibit the secretion of gastric acid and pancreas
