NSAIDs Flashcards
Give 4 examples of non-selective COX inhibitoirs
Paracetamol, Aspirin, Ibuprofen and Naproxen
Give 2 examples of COX-2 selective inhibitors
Celecoxib and Rofecoxib
What are the three main clinical qualities of NSAIDs?
Analgesic, anti-inflammatory and anti-pyretic.
Give an example of an irreversible COX inhibitor
Aspirin
Give an example of a competitive, reversible COX inhibtor
Ibuprofen
Give an example of a reversible, non-competitive COX inhibitor
Paracetemol
What is the main difference between COX-1 and COX-2?
COX-1 is in most tissues providing background levels of prostaglandins, whereas COX-2 is induced at sites of inflammation.
Give 6 main ADRs of NSAID use
Interactions (displacement of warfarin, sulphonylureas, and methotrexate etc.), gastric ulceration, reduced renal blood flow, bronchospasm in asthmatics, bleeding and rash.
What is the half-life of aspirin and what other clinical properties does it have?
Half an hour, and it reduces platelet aggregation aswell as suppress GI neoplasia.
What is the half life and maximum dosage of paracetemol?
2-4 hours, and it has a maximum dose of 8x500g/day.
How is paracetamol metabolised during 1st order kinetics?
60% is conjugated with glucoronide, 30% is conjugated with sulphate and 10% undergoes phase 1 metabolism to NAPQI, which goes on to phase 2 conjugation with glutathione.
How does zero order kinetic metabolism of paracetamol cause hepatotoxicity?
Phase 2 pathways become saturated and lots of paracetamol is converted to NAPQI, which is directly hepatotoxic, and glutiathione is depleted in NAPQI conjugation, allowing ROS to cause further hepatic damage.
How is NAPQI hepatotoxic?
Binds to mitochondria, causing necrosis.
What amount of paracetamol is potentially lethal?
10g or 20 tablets.
What main treatments can be given in paracetamol overdose?
Up to 4 hours after overdose, activated charcoal can be given which reduces intestinal paracetamol uptake, and up to 36 hours after overdose, intravenous N-acetylcysteine to increase glutathione reserves.
