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Flashcards in Gastrointestinal Drugs Deck (34)
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1
Q

What is the mechanism of action of Gaviscon?

A

It is a weak alkali so it neutralises stomach acid

Alginate component increases stomach content viscosity to decrease acid reflux

2
Q

What are the indications for gaviscon?

A

Pit is symptomatic relief for:

  • gastric/duodenal ulcers
  • gastro-oesophageal reflux
  • non-ulcer dyspepsia
3
Q

What are the contra-indications for gaviscon?

A

Hypophosphataemia (Al/Mg salts)

Renal impairment (Mg salts)

4
Q

What are the side-effects of gaviscon?

A

Magnesium salts = diarrhoea

Aluminium salts = constipation

5
Q

What are the interactions of gaviscon?

A

It decreases absorption of = ACE inhibitors, antibacterials, digoxin, iron

It increases excretion of Lithium

6
Q

What class of drug is ranitidine?

A

H2 antagonist

7
Q

What is the mechanism of action of ranitidine?

A

It competitively inhibits histamine actions at all H2 receptors, mainly inhibiting gastric acid secretions

Inhibits histamine/gastrin-stimulated secretions

8
Q

What are the indications for Ranitidine?

A

Benign gastric/duodenal ulcers
Chronic episodic dyspepsia
GORD

9
Q

What are the side effects of ranitidine?

A

Diarrhoea
GI/LFT disturbances
Headache/dizziness/fatigue
Rash

Rare: pancreatitis, bradycardia, AV block

10
Q

What are the interactions of ranitidine?

A

Cimetidine: inhibits P450 enzymes ⬇️ metabolism of oral anticoagulants, phenytoin, carbamazepine, quinidine, nifedipine, theophylline, TCAs

11
Q

What class of drug is omeprazole?

A

Proton Pump Inhibitor

12
Q

What is the mechanism of action of omeprazole?

A

Inhibits gastric acid secretion by dose-dependent inhibition of proton pump of gastric parietal cells
(blocks the hydrogen/potassium pump ATPase enzyme in parietal cells)

90% effective inhibition

13
Q

What are the indications for omeprazole?

A
GORD
dyspepsia
Oesophagitis
Gastric/duodenal ulcers
H. Pylori eradication
Zollinger-Ellison syndrome
14
Q

What are the cautions of omeprazole?

A

Liver disease
Breast feeding/pregnancy

May mask symptoms of gastric cancer

15
Q

What are the side-effects of omeprazole?

A

GI disturbances
Headache

Rare: dry mouth, peripheral oedema, pruritis

16
Q

What are the interactions of omeprazole?

A

Inhibits cytochrome p450 = ⬆️ plasma concentration of phenytoin, warfarin

17
Q

Where is omeprazole eliminated?

A

80% renal

20% faecal

18
Q

What class of drug is loperamide?

A

Anti-diarrhoeal agent

19
Q

What is the mechanism of action of loperamide?

A

It acts on opioid u receptors in the my enteric plexus

Inhibits acetylcholine release = inhibits peristalsis

20
Q

What are the indications for loperamide?

A

Acute diarrhoea

Chronic diarrhoea

21
Q

What are the contra-indications for using loperamide?

A

Active ulcerative colitis
Antibiotics associated colitis
Dysentery

22
Q

What are the side-effects of loperamide?

A
Abdominal cramps 
Dizziness/fatigue
Skin reactions (urticaria)
23
Q

What are the interactions of loperamide?

A

Desmopressin

24
Q

What class of drug is Senna?

A

Stimulant laxative

25
Q

What is the mechanism of action of Senna?

A

It is hydrolysed in the colon to produce anthracine glycoside derivatives

These directly stimulate the myenteric plexus = smooth muscle activity and defaecation

26
Q

What are the indications for Senna?

A

Constipation

27
Q

What are the contra-indications of Senna?

A

Intestinal obstruction

28
Q

What are the side effects of Senna?

A

Common: abdominal cramps/diarrhoea

Rare: hypokalaemia, colonic atony

29
Q

What class of drug is mesalazine?

A

Aminosalicylate

30
Q

What is the mechanism of action of mesalazine?

A

Releases 5-Aminosalicylate acid in the bowel

Unknown mechanism

31
Q

What are the indications for mesalazine?

A

Mild-moderate ulcerative colitis
Maintenance of remission
Rheumatoid arthritis

32
Q

What are the contra-indications of mesalazine?

A

Salicylate hypersensitivity

Renal impairment

33
Q

What are the side- effects of mesalazine?

A

GI effects:
Diarrhoea, nausea, vomiting, abdo discomfort

Rare: blood dyscrasias, low sperm count, tinnitus

34
Q

What class of drug is gaviscon?

A

Antacids