Painkillers + Paracetamol Flashcards Preview

OSCE Pharmacology > Painkillers + Paracetamol > Flashcards

Flashcards in Painkillers + Paracetamol Deck (12):
1

How do NSAIDs work?

Inhibit cox-1 & 2, reducing amount of prostaglandins produced in body

2

What are the good effects of NSAIDs

Reduced prostaglandins
- Reduce fever -> Il-1 usually triggers PgE to cause reset of thermostat in hypothalamus
- Reduces pain -> Prostaglandins usually sensitise nociceptors to painful sitmuli
- Reduce inflammation - Prostaglandins cause vasodilation and increased vascular permeability

3

Give 3 main ADRs of NSAIDs

- Reduced PgE2 leads to more permeable gastric mucosa and increases chances of ulcer formation
- Reduced PgE2 leads to constriction of the afferent arteriole in glomerulus, reducing GFR. Can cause Na+/K+/Cl- and H20 retention
- Prolongation of bleeding time (platelet inhibition)

4

Which COX causes all the bad side-effects of NSAIDs

COX-1

5

Give three DDIs of NSAIDs

Warfarin - Increase in concentration -> Increased bleeding
Methotrexate - Increase in concentration
Sulphonylureas - Increase conc -> Hypoglycaemia

6

How does aspirin inhibit Cox-1?

Acetylation irreversible

7

How is paracetamol usually metabolised?

Glucoronide (60%) or sulphates (30%) in Phase II metabolism

8

What happens if you take paracetamol overdose/

Enters phase one metabolism
NAPQI produced
Conjugates with glutathione
Hepatocellular necrosis occurs

9

How do you treat paracetamol overdose

0-4 hrs -> Charcoal
0-36 hours -> N-acetylcysteine

10

How do opioids work?

Act pre-synaptically -> Open K+ channels, hyperpolarising neurone and decrease synaptic transmission

Also close voltage gates Ca2+ channels, inhibits release of substance P neurotransmitter

11

Give three ADRs of opiates

Respiratory depression
Miosis
Constipation

12

Give a DDI of opiates

Naloxone - Opioid receptor antagonist. Reverses the adverse antagonistic effects.