Gastrointestinal Drugs Flashcards
(59 cards)
1
Q
What are Proton Pump Inhibitors indicated in?
A
- Peptic Ulcers
- Acid
- Dyspepsia
- H. Pylori
2
Q
What is the MOA of Proton Pump Inhibitors?
A
- Irreversibly inhibit H/K-ATPase in gastric parietal cells which reduces gastric acid secretion.
3
Q
What are the main Side effects of Proton pump Inhibitors:
A
- GI upset
- Headaches
- Long term = hypomagnesaemia
- osteoporosis
- Increases Gastric pH which may reduce the body’s host against defence.
4
Q
What are PPIs contraindicated in?
A
- May disguise symptoms of gastro-oesophageal cancer
- In elderly, can increase risk of fracture due to risk of osteoporosis.
5
Q
What are the key interactions of Proton Pump Inhibitors?
A
- Omeprazole can reduce the antiplatelet effect of clopidogrel by decreasing its activation
- Lansoprazole and Pantoprazole have a lower propensity to interact with clopidogrel (thus preferred when prescribing alongside clopidogrel).
6
Q
What are H2 receptor Antagonists indicated in?
A
- NSAID-associated ulcers
- Gastric and duodenal ulcers
- Dyspepsia and GORD
7
Q
What is the MOA of H2 receptor antagonists?
A
- reduce gastric acid secretion
- Proton pump of gastric parietal cell produces acid by secreting H+ into stomach lumen in exchange for K+, which is regulated by histamine
- Blocks histamine H2-receptors on the gastric parietal cells which inhibits release of H+ by the proton pump, via a 2nd messenger system reduces gastric acid secretion
8
Q
What are the main sides effects of H2 receptor antagonists?
A
- Bowel disturbances (diarrhoea and Constipation)
- headaches
- Dizziness
- Hypotension
- dark Urine
- alopecia
9
Q
whom is H2 receptor antagonists contraindicated in?
A
- renal impairment (low dose)
- may disguise symptoms of oesophageal cancer.
10
Q
What are 2 examples of PPIs?
A
Omeprazole
lanzoprazole
11
Q
What is an example of H2 receptor antagonist?
A
- Ranitidine
- (-tidine)
12
Q
What is an example of an antacid?
A
- Gaviscon
- Sodium bicarbonate
- Calcium carbonate
13
Q
What is the main indications of antacids?
A
- Dyspepsia
- heartburn
- GORD
14
Q
What is the MOA of antacids?
A
- alkali to neutralise stomach acid
15
Q
What are the side effects of antacids:
A
Diarrhoea, constipation, Flatulence, cramps, nausea, vomitting
16
Q
What is the MOA of alginates?
A
- Increase viscosity of stomach contents which reduces the reflux of stomach acid into oesophagus
- After reacting with stomach acid, they form a floating ‘raft’ which separates gastric contents from the gastro-oesophageal junction to prevents mucosal damage
- May also inhibit pepsin production
17
Q
What are some examples of alginates:
A
- Magnesium salts
- Aluminium salts
18
Q
What are the main side effects of each alginate salt?
A
- Magnesium salts- diarrhoea
- Aluminium salts- constipation
19
Q
Whom is antacids contraindicated in?
A
- Compound alginates should not be given with thickened milk preparations to children as it can cause bloating and discomfort
- Na/K containing preparations used with caution in: Fluid overload and Hyperkalaemia (e.g. renal failure)
- Sucrose preparations can worsen hyperglycaemia in diabetic patients
20
Q
What drugs do Antacids interact with?
A
- The divalent cations in compound alginates can bind to other drugs which reduces their absorption
To ensure drug is absorbed ensure dose separated by 2 hours with:
- ACE-inhibitors
- Some antibiotics (e.g. tetracyclines, cephalosporins)
- Bisphosphonates
- Digoxin
- Levothyroxine
- PPIs
Increases the alkalinity of urine meaning it can increase excretion of:
- Aspirin
- Lithium
21
Q
What is Loperamide used for?
A
- Diarrhoea
- IBS
- viral gastroenteritis
22
Q
What are the main side effects of Loperamide?
A
- Constipation
- cramps
- Flatulence
23
Q
Who is Loperamide contraindicated in?
A
- acute ulcerative colitis
- acute bloody diarrhoea
24
Q
What are antiemetics used for?
A
- treatment of nausea and vomitting.
- prophylaxis
25
What are the 4 classes of antiemetics?
- H1 receptor antagonist
- D2 receptor antagonist
- 5HT3 receptor antagonist
- Anti-muscarinic
26
Give an example of a H1 receptor antagonist?
- Cyclizine
27
Give an example of a D2 receptor antagonist?
Metoclopramide
28
Give an example of a 5HT3 receptor antagonist?
- Ondansetron
29
Give an example of an Anti-muscarinic drug?
Hycosine Hydrobromide
30
What is the MOA of D2 antagonist?
- Acts in the brain and the gut
- Inhibits D2 receptors in the chemoreceptor trigger zone which is responsible for sensing emetogenic substances in the blood, therefore effective in nausea and vomiting caused by CTZ stimulation.
- Prokinetic effect: increases LOS and gastric tone which promotes gastric emptying, then contributes to their antiemetic action in conditions associated with reduced gut motility
31
What are the main side effects of D2 receptor antagonists?
- diarrhoea
- movement abnormalities/ tremours
- seizures
- low mood
32
What is Metoclopramide contraindicated in?
- Should not be prescribed for more than 5 days to reduce the risk of extrapyramidal effects
Avoid in:
- Neonates
- Children
- Young adults
- Intestinal obstruction
- Perforation
- Parkinson’s disease
33
What drugs does D2 receptor antagonists interact with?
- antipsychotics
- dopaminergic agents especially in parkinson's disease.
34
What is the MOA of H1 receptor antagonist?
Blocks the H1 receptor and muscarinic Ach receptors which triggers nausea in the brain.
35
Side effects of H1 receptor antagonists:
- depression
- drowsy
- dry mouth
36
What is the MOA of Antimuscarinic in IBS:
- reduces motility
- reduces glandular secretions
- reduced sphincter
- causing muscle dilation
37
What are the 4 types of laxatives?
- Bulk Forming
- Stimulant
- Osmotic
- Feacal Softeners
38
Name a bulk-forming laxative?
Ispaghula
39
Name a stimulant laxative:
- Senna
- Bisacodyl
40
Name a osmotic Laxative:
Lactulose
41
Name a Feacal Softening Laxative:
Docusate
42
What is the MOA of bulk forming Laxative:
- retains fluid in the stool causing an increase in feacal mass which triggers peristalsis and soft stools.
43
What are the indications for bulk-forming laxatives?
- a low faecal mass
44
Whom are the bulk-forming laxatives contraindicated in?
- elderly and frail
45
What are the side effects of using bulk-forming laxatives:
- bloating
- flatulence
46
Which is the most rapid form of laxative?
Stimulant- takes 6-12 hours to work
Faecal softeners- 12-72 hours to work
47
What is the MOA of stimulant laxatives?
- increases the intestinal motility which via stimulation of nerves via peristalsis.
- Increases water and electrolyte secretion from the colonic mucosa causing an increase in the volume of colonic content and stimulates peristalsis.
48
What are some side effects of stimulant laxatives?
- cramps
- diarrhoea
- malanosis coli
49
What is Stimulant laxative indicated in?
A slow transit
50
What is Osmotic laxative indicated in?
- Pellet stools
51
Whom is Osmotic laxative contraindicated in?
- IBS
- Constipation
- Faecal impactation
- bowel preparations for procedures
- hepatic encephalopathy
52
What is the MOA of Osmotic laxative?
- increase in H2O in the large intestine by drawing fluid from body/ retaining the fluid.
53
What are the common side effects of Osmotic laxatives?
- nausea
- dehydration
- flatulence
- bloating
- cramps
54
What are Faecal softeners (laxatives) indicated in?
- Hard stools
55
What is the MOA of Faecal softners?
- Reduces the surface tension of stools to increase penetration of intestinal fluid into the faecal mass
- use alongside another laxative.
56
What is the side effects of Faecal softeners?
- cramps
- diarrhoea
57
When is giving laxative to patients contraindicated?
Intestinal obstruction
58
How do you treat Helicobacter Pylori?
- Omeprazole + Amoxicillin + (Clarithromycin OR Metronidazole) for 7 days
59
How do you treat C. Difficile:
- Vancomycin 1st line
