GI examination - Peptic ulcers, laxatives, constipators Flashcards Preview

OSCE Pharmacology > GI examination - Peptic ulcers, laxatives, constipators > Flashcards

Flashcards in GI examination - Peptic ulcers, laxatives, constipators Deck (39):
1

What is the mechanism of action of omeprazole?

 Prevents H+ ions being pumped into parietal cell canaliculi by targeting ATPase
 Only works if you eat (you need proton pumps working for it to bind)

2

What is the mechanism of action of histamine

Cimetidine
 Removes the amplification of Gastrin/Ach signal by acting as a Histamine Receptor Antagonist

3

How do you treat Gord?

o Lifestyle
o Antacids
o H2 Receptor Antagonists
o PPI

4

Give four adverse reactions to PPIs

o GI upset
o Nausea
o Headaches
o Risk of gastric atrophy with long-term treatment

5

Give four H2 receptor antagonists

o Dizziness
o Fatigue
o Gynaecomastia
o Rash

6

What is h.Pylori triple therapy

PAC
Proton pump inhibitor
Two antibiotics - Amoxicillin/Clarithromycin

7

When are PPIs used?

 Short term treatment of peptic ulcers
 Severe GORD
 Confirmed oesophagitis
 Eradication of H. Pylori (part of triple therapy)
 Zollinger-Ellison Syndrome (Gastrin secreting pancreatic tumour)

8

What is the mechanism of action of PPI?

 Irreversibly inhibit Na/K-ATPase that is responsible for proton secretion from parietal cells.

9

Give the main ADRs associated with PPI

GI upset, nausea
Headaches
Gastric atrophy

10

Give a key DDI of omeprazole

 Omeprazole is a CYP450 enzyme inhibitor
 Avoid use with patients being treated with Warfarin, Phenytoin etc.

11

How long do PPI take to work?

PPI action is delayed as not all pups are active all of the time. Maximum efficacy is after 2-3 days and only works if you eat as existing acid has to be pumped out into intestine.

12

What are the two indications for H2 antagonists?

Peptic ulcer disease and GORD

13

How do H2 antagonists work?

 Competitively antagonist H2 receptors, blocking the amplifying action of Histamine on Parietal cells

14

What are four key ADRs for H2 antagonists?

 Dizziness
 Fatigue
 Gynaecomastia
 Rash

15

What is a key DDI of H2 antagonists?

 Cimetidine is a CYP450 enzyme inhibitor
 Avoid use with patients being treated with Warfarin, Phenytoin etc

16

When are H2 antagonists given?

At night when food buffering at lowest

17

Name four types of laxative

Bulk laxatives
Faecal softeners
Osmotic laxatives
Stimulant laxative

18

When would you give bulk laxative?

Constipation

19

What is the mechanism of action of bulk laxatives

Increases the volume of non-absorbable solid residue in the gut , distending the colon and stimulating peristaltic movements

20

When should you not use a bulk lax?

 Dysphagia
 Intestinal obstruction (Adhesions, ulceration)
 Colonic atony
 Faecal impaction

21

What are three adverse reactions to bulk laxatives?

 Flatulence
 Abdominal distension
 GI obstruction

22

Name an osmotic laxative

Lactulose

23

What is the mechanism of action of osmotic laxatives

 Increase water content of the bowel via osmosis
 Lactulose – Disaccharide (galactose/fructose) that cannot be hydrolysed by digestive enzymes. The fermentation of lactulose by colonic bacteria gives acetic and lactic acid. This has an osmotic effect

24

When should you not use osmotic laxative?

Constipation

25

Give four ADRs of osmotic laxatives

 Flatulence
 Cramps
 Abdominal discomfort
 Caution required to prevent intestinal obstruction

26

Give an anti-diarrhoeal

Codeine

27

When should anti-diarrhoeals NOT be used

Inflammatory bowel disease - Toxic mega colon

28

What is the mechanism of action of codeine anti-diarrhoeals

 Act on opioid receptors in the bowel
 Reduce motility (increase time for fluid reabsorption)
 Increase anal tone and reduce sensory defecation reflex

29

Anti-diarrhoeals adverse reactions (5)

 Nausea, vomiting, abdominal cramps, constipation drowsiness

30

What is one anti-diarrhoeal with super good morphine effects`

Imodium, can't penetrate BBB, super effective

31

How do bulk forming anti-diarrhoeals work?

Relatively small amount of faecal fluid influences composition.

32

What is IBS?

Chronic:
o Abdominal Pain
o Discomfort
o Bloating
o Alteration of Bowel Habits

33

Give process of vomiting

o Pyloric sphincter closes while the cardia and oesophagus relax
o Gastric contents propelled by contraction of abdominal wall and diaphragm
o Glottis closes with elevation of soft palate, preventing entry of vomit into the trachea and Nasopharynx
 If vomiting is due to alcohol, or patient has a cranial nerve lesion they are at a higher risk of aspiration as this does not work properly

34

Give 3 types of anti-emetics

Dopamine receptor antagonist
Serotonin antagonist
Muscarinic receptor antagonist

35

What is the mechanism of action of vomtiing

Things (medication, smell, touch, raised ICP, stomach) stimulate postrema on floor of 4th ventricle
Vestibular apparatus disturbance
Both stimulate medullary centre, whcih releases aCh, histamine and serotonin, which causes vomiting

36

How do dopamine receptor antagonists work?

 Acts on the Postrema on the floor of the 4th ventricle
 Acts on the stomach to increase the rate of gastric emptying

37

What are three ADRs of dopamine receptor antagonists

 Stimulates prolactin release
 Metoclopramide – extra-pyramidal reactions (dystonia) occur in 1%, therefore is avoided in Parkinson’s disease
 Galactorrhoea – Can induce pro-lactin

38

What is the mechanism of action of serotonin antagonists?

 5-HT is released into the gut, reducing Vagus activity, therefore effective at deactivating the vomiting centre (the Postrema on the floor of the 4th ventricle)
 Blocks Serotonin receptors in Chemoreceptor Trigger Zone

39

What are three ADRs of serotonin antangonists

 Headaches, constipation, flushing