T+O Drugs Flashcards
What is the MOA of NSAIDs
Inhibits prostaglandin production by cycloxygenase (COX)
Inhibition of which COX mediates the effects of NSAIDs as an analgesic
COX2 (inducible form)
What is an alternative to NSAIDs with a better side-effect profile and why
Selective COX2 inhibitors. As they do not inhibit gastroprotective prostaglandins produced by COX1
Name a selective COX2 inhibitor
etoricoxib
What are the 3 main adverse effects of NSAIDs
- GI haemorrhage
- Increased risk of cardiovascular events
- Renal impairment
Of the NSAIDs, which has the lowest risk of GI impairment
Ibuprofen
Which NSAIDs has lowest risk of cardiovascular events
Naproxen
What is the problem with COX2 inhibitors
Higher risk of cardiovascular events compared to standard NSAIDs
What are two other side effects of NSAIDs
Fluid retention
Hypersensitivity reaction
What conditions may fluid retention worsen
HTN
Heart Failure
What are 4 absolute contraindications of NSAIDs
- Heart Failure
- Liver disease
- Severe renal impairment
- NSAID hypersensitivity
What are 4 relative contraindications of NSAIDs
Risk of adverse events:
- Peptic ulcer
- CVD
- GI bleed
- Renal impairment
What drugs increase the risk of peptic ulceration with NSAIDs
Aspirin Anticoagulants Corticosteroids Venlafaxine SSRIs
What drugs do NSAIDs reduce the effectiveness of
Antihypertensives
What toxic substance accumulates in paracetamol overdose
N-acetyl-p-benzoquinone imine (NAPQI)
How is paracetamol overdose treated
acetyl cysteine
In which individuals should the dose of paracetamol be reduced
those at risk of overdose due to increased NAPQI or reduced glutathione stores
Which individuals are at risk of paracetamol OD due to excess NAPQI production
Chronic alcoholics
Which individuals are at risk of paracetamol OD due to reduced glutathione stores
Malnutrition
Low Body Weight <50Kg
Explain which drugs interact with paracetamol
CYP inducers carbamazepine and phenytoin increase the rate of NAPQI production and risk of liver toxicity after paracetamol OD
What are the 3 routes of administration of paracetamol
PO, IV infusion, Rectal
What is the usual dose of paracetamol
0.5 - 1g 4-6hrly
What is maximum dose of paracetamol allowed
4g per day
When are effects of paracetamol felt
30m after
