PBL 1

Question 1

what are the indications for loperamide?

Answer 1

control and symptomatic relief of acute nonspecific diarrhoea and chronic diarrhoea associated with IBD

Question 2

what is loparamides moa?

Answer 2

its a non-selective Ca2+ channel blocker and binds to opioid mu-receptors in the myenteric plexus in the large intestine
it decreases myenteric plexus activity which decreases motility, this increases the time substances stay in the intestine and so increases water absorption = decreases colonic mass moveemnts

Question 3

what are the 2 main classifications for antispasmodics?

Answer 3

antimuscarinics (anticholinergics) and smooth muscle relaxants

Question 4

what do antimuscarinics do?

Answer 4

reduce intestinal motility

Question 5

what are antimuscarinics used for?

Answer 5

gastrointestinal smooth muscle spasm

Question 6

what are examples of antimuscarinics?

Answer 6

atropine sulface
diccloverine hydrochloride
propantheline bromide
hyoscine butylbromide

Question 7

what are smooth muscle relaxants used for?

Answer 7

relieveing abdominal pain or spasm in IBS

Question 8

what are examples of smooth muscle relaxants?

Answer 8

Alverine citrate, mebeverine hydrochloride, and peppermint oil

Question 9

what is azathioprine used for?

Answer 9

IBD as its an immunosuppressive drug

Question 10

what is azathioprines moa?

Answer 10

inhibits purine synthesis so less DNA and RNA are formed = less synthesis of WBCs = immunosuppression

Question 11

what are examples of aminosalicylates?

Answer 11

5-aminosalicylate and sulfasalazine

Question 12

what is sulfasalazines moa?

Answer 12

inhibits folic acid and splits into its metabolites 5-ASA and sulfapyridine

Question 13

why do we often give 5-ASA alone rather than as a product of sulfasalazine breakdown?

Answer 13

as sulfapyridine (also a breakdown product of sulfasalazine) has side effects

Question 14

why can 5-ASA have topical effects on the colonic epithelium? (why not digested before)

Answer 14

its poorly absorbed by the intestine and systemic circulation

Question 15

outline 5-ASAs moa?

Answer 15

its metabolised in the colon into N-acetyl-5-ASA by N-acetyl-transferase-1. It then binds a nulcear hormone receptor which induces the translocation into the cell nucleus with the reception. here it can control transcription and modulate the expression of pro-inflammatory cytokines and prostaglandins

Question 16

what are some major causes of GI bleeding?

Answer 16

peptic ulcer disease
erosive esophagitis
oesophageal varices
arteriovenous malform
mallory-weiss syndrome
cancers
gastritis

Question 17

what can cause lower GI bleeds?

Answer 17

diverticulosis
haemorrhoids
fissures
fistulas
arteriovenous malformations
intestinal ischaemia