Pain Flashcards
Mechanism of action if diclofenac ?
- Reversible inhibition of COX-1 and COX-2
- decreased prostaglandin synthesis
Indications for diclofenac ?
- inflammatory conditions (RA, ost op pain, acute gout)
- pain
- Pyrexia
What drug class is diclofenac ?
NSAID
Contraindications for diclofenac
- aspirin/NSAID hypersensitivity
- renal impairment
- peptic ulcers, active or history of recurrent
- SLE
- hyperkalaemia
Route of elimination of diclofenac
Kidneys
Side effects of diclofenac ?
- nausea/GI Disturbance
- dizziness
- deceased renal function
- increased blood pressure
Possible interactions of diclofenac ?.
- ACEi : increased risk of renal impairment
- SSRIs: increased risk of bleeding
- B blockers, Ca channel blockers: NSAIDS antagonise hypertensive effects
Drug class of codeine ?
Opiate
How does codeine work ?
- Mimics endogenous opioids (e.g. Endorphins)
- acts on opioid receptors in brain (dorsal horn and grey matter) and PNS
- cause analgesic effects
Indications for codeine
- mild- moderate pain
- diarrhoea
- cough suppression
Contraindications of codeine
- acute respiratory depression
- paralytic ileus
- conditions associated with raided ICP and head injury as interferes with pupil light response
Side effects of codeine
- Nausea and vomiting
- constipation
- dry mouth
- biliary spasm
Possible interactions of codeine ?
Alcohol: enhanced hypotensive/sedative effects
Metoclopramide: antagonise effects of GI activity
cimetidine: inhibits opioid metabolism
Elimination of codeine ?
Kidneys
What drug class is morphine ?
Opioid
Mechanism of action of morphine
- Agonist of opioid receptors (mu receptor), producing an analgesic effect by inhibiting signalling along pain pathways
- mu receptor mediates sedation, euphoria, inhibits respiration and GI Peristalsis
Side effects of morphine
- constipation
- nausea and vomiting
- hypotension
- pruritis
- respiratory depression
- sedation
Indications for morphine
- moderate-severe acute pain
- sever chronic pain
- intractable cough in palliative care
Contraindications if morphine
- severe resp disease e.g. Asthma, COPD
- head injury/ raised ICP
- alcohol ingestion
- convulsive disorders
Main route if elimination of morphine ?
Liver
Interactions of morphine
- alcohol
- CNS depressants
Mechanism of action of paracetamol
- inhibits COX 3 enzymes resulting in analgesic and anti pyretic effects but not anti inflammatory
Side effects of paracetamol ?
- headache
- nausea
- Hepatotoxicity
Indications for paracetamol
- Mild-mod pain
- fever
Contraindications of paracetamol
- hepatic disease
- alcohol
Route of elimination of paracetamol
Liver
Possible interactions of paracetamol
Carbamazepine: increased paracetamol metabolism
Cyt p450
What is the antidote to paracetamol overdose ?
N-acetylcysteine
