GI

Question 1

How does loperamide work?

Answer 1

1. Symptomatic treatment for diarrhoea
2. Loperamide is an opioid-receptor agonist and reduces GI tract motility
3. Bowel content is slowed, allowing for more water to be absorbed from the faecal matter.

Question 2

What is the mechanism of action of naproxen (NSAID)?

Answer 2

(1. ) NSAIDs exert their effects by inhibiting cyclo-oxygenase (COX) which synthesis prostaglandins and thromboxane from arachidonic acid.
(2. ) COX-1 is constitutively present in normal cells whereas COX-2 is induced by inflammatory cells.
(2. ) Inhibition of COX-2 is most likely the mechanism for analgesia.

Question 3

What contra-indications are there to using NSAIDs? (5)

Answer 3

(1. ) CI =
- active/recurrent GI bleeding
- active/recurrent GI ulceration
- severe heart failure.
- allergy to aspirin or NSAIDs
- should be avoided in renal failure and dehydration.

Question 4

Why should we avoid giving NSAIDs to patients with asthma?

Answer 4

Between 8 - 20% of adult asthmatics experience bronchospasm following ingestion of aspirin and other NSAIDs, this reaction is potentially fatal.

Question 5

How do NSAIDs cause renal dysfunction?

Answer 5

(1. ) Inhibition prostaglandins synthesis, which is involved in the maintenance of renal medullary blood flow.
(2. ) Neonates and elderly are at risk as are patients with heart, liver and renal disease or a reduced circulating blood volume.