GIT Lec 2 Pt 2 - Enhancmenet Of Mucosal Resistance

Question 1

How do we enhance the mucosal resistance?

Answer 1

1. Prevention of damage to the mucosa
2. Reducing inflammation
3. Healing existing ulcers

Question 2

What are the two methods to enhance the mucosal resistance?

Answer 2

A. Protection of the site of the ulcer
B. Cytoprotection

Question 3

(Protection of base of ulcer) what is the dosage and frequency of Colloidal Bismuth?

Answer 3

10mg, B.I.D, half an hour or two hours after meals (breakfast and dinner)

Question 4

(Protection of base of ulcer) what is the MOA of bismuth subsalicylate?

Answer 4

1. It selectively chelates the protein material at the base of the ulcer, creating a protein coat that protects the ulcer site from further damage via gastric acids, pepsin and bile.
2. It’s thought to stimulate mucous secretion.
3. It has anti-H.pylori action.
4. Its efficacy is approximate to H2-receptor antagonists.

Question 5

(Protection of base of ulcer) what are the indications of colloidal bismuth?

Answer 5

1. Benign gastric and duodenal ulcers.
2. Treatment of acute diarrhea and prevention of traveler’s diarrhea.

Question 6

What are the side effects of bismuth subsalicylate?

Answer 6

1. Darkening of the tongue, teeth and stool when taken orally as a syrup.
2. Systemic effects: encephalopathy and athropathy.

Question 7

What is the MOA of Sucralfate?

Answer 7

• Sucralfate is a complex of aluminum hydroxide and sucrose octasulphate, in the acidic environment of the stomach, the compound breaks down into aluminum and sulfate sucrose ions, the latter are negatively charged ions which electrostatically bind to proteins of both the normal and necrotic mucosa creating a gel on the epithelial cells thereby protecting them.
• Sucralfate also binds to pepsin and intestinal secretions and inactivates them
• it increases the production of mucous, PG’s and bicarbonate which are protective agents.
• it stimulates healing by angiogenesis and formation of granulation tissue.
• it’s used for long term prevention of ulcers (long term maintenance)

Question 8

What are the indications of Sucralfate?

Answer 8

1. Chronic duodenal ulcers.
2. Are not used for the treatment of NSAID induced ulcers.
3. Maintenance medication: used to prevent relapses of ulcers.
4. Efficacy is equal to that of H2-antagonists

Question 9

What are the side effects of Sucralfate?

Answer 9

Only constipation

Question 10

What are the drug interactions of Sucralfate?

Answer 10

Since it only works in acidic environment, it should NOT be taken with antacids, H2-blockers or PPI’s.
It also decreases the the absorption of other drugs like: ciprofloxacin, theophylline (not used anymore), digoxin, phenytoin, and amitriptyline because of its binding with them.

Question 11

What are some of the prostaglandin analogues?

Answer 11

1. Misoprostol (200 mg) taken every 6 hours (4 times a day); PGE1 analogue
2. Rioprostil; synthetic PGE1
3. Enprostil and Arbaprostil; PGE2 derivatives.

Question 12

What is the mechanism of action of PGE analogues?

Answer 12

1. They inhibit the production of HCl by blocking the secretion of histamine which decreases the production of adenyl Cyclase which in turn decreases the production of cAMP which leads to the inactivation of the H-k-Proton pump.
2. They maintain mucosal blood flow
3. They promote epithelial cells regeneration thereby hastening the repair of the damaged mucosa
4. They prevent luminal H+ ions from diffusing back into the mucosa
   PPI’s are just as effective as PGE analogues and are better tolerated.

Question 13

What are the indications of PGE analogues?

Answer 13

1. Drug of choice for the treatment of NSAID induced ulcers (PPI’s are just as effective and better tolerated)
2. Chronic gastric and duodenal ulcers

Question 14

What are the S/E of PGE analogues?

Answer 14

1. Uterine contractions and dislodging of fetus (contraindicated in pregnancy due to risk of abortion)
2. Diarrhea and nausea; both are dose related.