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Flashcards in Ulcers Deck (21):
1

Parietal Cell Stimulation

Gastrin-G Cells
Histamine-ECL
Ach-Vagus

2

Aggressive Factors

H. Pylori
Acid/Pepsin
NSAIDs
Bile Salts
Smoking

3

Defensive Factors

HCO3-
Mucousa
Blood Flow
Phospholipids
Free radical scavengers

4

H. Pylori

Thrives under low pH
Binds surface epithelium
Decreases HCO3- production
Secretes immunogenic proteins
Immune cell invasion and inflammation

5

H2 Antagonists

Cimetidine, ranetidine
Structurally similar to Histamine
Blocks Histamine at H2 receptors on Parietal Cells
Heals 70-80% in 4-8 weeks (90% relapse 1 year)
Use: Prevention, healing, Zollinger-Ellison Syndrome
Oral-OTC and Rx

6

H2 Antagonists- Kinetics and SEs

Well absorbed by gut, food and antacids reduce this
Metabolised by liver, excreted in urine
Inhibits CYP450- Warfarin, lignocaine, phenytoin
SE: Headache, diarrhoea, rash

7

PPIs

Omeprazole, Lansoprazole, Rabeprazole
Acid labile prodrug
Disulfide covalent bonds with H/K ATPase
Irreversible inhibition (95% secretion for 1-2 days)

8

PPIs Use

NSAID ulcers
Gastric ulcers
H. Pylori eradication
Zollinger-Ellison Syndrome
GORD

9

PPIs Kinetics

Oral- enteric-coated form to bypass stomach
Dissolved and absorbed in small intestine
Highly protein bound
Extensively metabolised by liver and eliminated in urine
Interfere with low pH dependent absorption
Interfere with metabolism of diazepam, phenytoin

10

PPIs Side Effects

Abdominal pain
Diarrhoea-C. Diff
N and V
Hypomagnesia
Osteoperosis
Pneumonia

11

Anticholinergics

Pirenzepine
Muscarinic M1 antagonist
Block Ach mediated histamine release from gastric paracrine cells
Original anti-ulcer drug
Used in PUD
Other anticholinergics have too many side effects

12

Antacids

Aluminium and Magnesium Hydroxides, Sodium Bicarbonate
MOA: Chemical antagonism
Al3+ and Mg2+ bind and neutralise pepsin
Use: to relieve pain and promote healing in PUD
To relieve symptoms of acid indigestion, heart burn, GORD, dyspepsia

13

Antacids Kinetics and SEs

Liquids more effective than tablets
Distributed throughout GIT, eliminated in faeces
All antacids can interfere with the absorption of oral drugs given at same time
SE: Aluminium- Constipation. Magnesium- Diarrhoea
Give them together

14

Mucosal protectant-Sucralfate

MOA: Viscous polymer at pH<4 of sucrose octasulphate and Al hydroxide
Adheres to necrotic ulcer tissue- pos glycoproteins
Forms protective barrier to acid, pepsin and bile
May stimulate PG synthesis, increasing mucus and bicarbonate
Use: PUD

15

Sucralfate Kinetics and SEs

Protective barrier-6 hours
Not absorbed- good for liver disease patients
Can bind other medications-digoxin
SE: Constipation

16

Mucosal Protectant- Colloidal Bismuth

MOA: Selective binding to ulcer crater protecting it from acid and pepsin
May inhibit activity of pepsin, stimulate mucus production
Toxic to H. Pylori
Use: PUD
Few SEs

17

Mucosal Protectants- Misoprostol

MOA: Synthetic Prostaglandin E1
Protects gastric lining- inhibiting acid and promoting mucus and HCO3-
Use: Prevention of NSAID induced ulcers
SE: Diarrhoea, uterine contractions

18

Tests for Initial Diagnosis of H. Pylori

Urea breath test and Stool Assay- Non-invasive, sensitive, specific. PPIs can interfere with Breath Test, not Stool
Serology: Fairly sensitive and specific
Endoscopy: antral and fundal biopsy- not reqired for diagnosis. May check for cancer

19

H. Pylori Treatment

Triple- 1-2 weeks, PPI, Amoxicillin, Clarithromycin
Quad- Tetracycline, metronidazole(resistance), PPI, bismuth
Dual- PPI and Amoxicillin/Clarithromycin
90% eradication
SE- too many to list

20

Success For H. Pylori

Compliance
Antibiotic resistance
Duration of Therapy
Correct dosing

21

Diseases Associated with H. Pylori

PUD- 60% reoccurrence if not eradicated
Bleeding duodenal ulcer- 30% rebleeding in 1 year
Gastric cancer- justified in early cancer, 9% recurrence of tumor in untreated control