What is the MOA of morphine?
G protein coupled receptors which increase adenylate cyclase to reduce intracellular cAMP content.
What is morphine metabolised to?
morphine-6-glucuronide which contributes to action
what is the plasma half life of morphine and how is it excreted?
- Half life: 3-6hours
- Excreted: renally
Give 6 SE of morphine
- 1. respiratory depression
- 2. N&V
- 3. constipation, reduce GI motility and so reduce absorption of other drugs
- 4. pupil constriction
- 5. mast cell release histamine so bronchoconstriction and hypotension
- 6. EUPHORIAAAAA
What does tolerance mean?
Need higher dose to get the same effect
What does dependance mean?
When come off it, get withdrawal symptoms and cant sleep, nausea…cravings
Apart from morphine overdose, when else is naloxone needed?
Give to neonate im if pethidine used in labour
What is the half life of naloxone, why is it important?
Only 2-4 hours so may need to be repeated or given by infusion as morphine half life is 3-6 hours.
Apart from analgesia, what other property does codeine have?
How does codeine work?
Converted to morphine
What is codeine’s main SE?
What is the MOA of tramadol…careful!
- 2 MOA – one opioid agonist
- Also NA/5HT reuptake inhibitor
What are the properties of fentanyl? And 2 main uses
- Highly potent and short acting
- Use: anaesthesia, palliative care (patches and lollipops)
What are the main SE or unwanted effects of pethidine
- Restlessness (not sedation unlike morphine)
- Anti-muscarinic: dry mouth, blurred vision
Why is pethidine used in labour?
Short acting so safer
What is methadone used for?
Heroin and morphine addiction
What is the half life of methadone?
Over 24 hours. Good as less sedative than morphine. It is a synthetic opioid
Give 4 uses of NSAIDs
- 1. anti-inflammatory eg in arthritis
- 2. pain relief for orthopaedic pts – no evidence that NSAIDs reduce bone healing
- 3. opiate sparing
- 4. closure of patent ductus arteriosus
what is MOA of NSAIDs?
COX inhibit so less PG and TXA2 made
What is the difference between COX1 and COX2?
- COX1: constitutive – eg gastric mucosa protected by it
- COX2: inducible – formation of pro-inflammatory mediators
What are 4 ‘a’ effects of NSAIDs?
Which 4 systems are affected by NSAIDs? (SE)
- GI: gastritis, bleeds
- Renal: reduced PG means less vascular tone so makes renal failure worse
- Respiratory: bronchoconstriction
- Cardiac: CCF, pedal oedema
What is the MOA of aspirin?
IRREVERSIBLE COX 1 and 2 inhibitor
What additional SE does aspirin have?
- Dizziness, deafness, tinnitus
- Reye’s syndrome (liver failure in children who take aspirin)
- Drug interactions as aspirin is highly protein bound so interacts with warfarin
What is the MOA of paracetamol?
What are the 2 main effects of paracetamol?
What is the MOA of gabapentin?
- Binds VGCC, acts at glycine site of NMDA receptor, subsP
What are the SE of amitryptiline?