Pain Management Flashcards
(36 cards)
What are the types of pain?
Acute
Chronic- nociceptive, neuropathic (central/peripheral), visceral and mixed
What are some examples of nociceptive and neuropathic pain?
Nociceptive- osteoarthritis, rheumatoid arthritis
Neuropathic central- post stroke, MS, spinal cord injury, migraine, HIV related
Neuropathic peripheral- post hepatic neuralgia, diabetic neuropathy
What are some examples of mixed pain?
Lower back
Cancer
Fibromyalgia
What are some examples of visceral pain?
Internal organ
Pancreatitis
IBS
What are the goals for treating post-surgical pain?
Patient comfort and satisfaction
Easier mobilisation
Reduce hospital stay and costs
What are the goals of treating pain generally?
Minimise stress response/neuroendocrine effects
Minimise adverse effects on respiratory, cardiovascular, GI, urinary and musculoskeletal systems
What is the WHO pain ladder?
Step 1- simple analgesics e.g aspirin, paracetemol
Step 2- opioids suitable for mild to moderate pain and simple analgesics
Step 3- opioids suitable for use in severe pain and simple analgesics
How much paracetamol has to be taken for liver damage?
14 tablets
Treatment with acetylcysteine
How do NSAIDs work?
Inhibit COX responsible for arachidonate metabolism of cyclic endoperoxides, preventing formation of prostaglandins and thromboxanes
Analgesic, antipyretic, anti-inflammatory
What are the adverse effects of NSAIDs?
GI tract- GIT erosion and ulceration
Renal- reduced blood flow, acute failure, sodium, potassium and water retention
Respiratory- bronchospasm
Haematological- reduce platelet aggregation (aspirin irreversible, NSAIDs reversible)
What should you take precaution with when prescribing NSAIDs?
Used at lowest effective dose, shortest period of time, regular review
Co-prescription of PPI
No support to use coxs alone before NSAIDs and PPI
What are examples of weak opioids?
Codeine
Dihydrocodeine
Dextropropoxyphene
Tramadol
What are examples of strong opioids?
Morphine Diamorphine Oxycodone Buprenorphine Fentanyl
When are weak opioids most effective?
When used in combination with paracetamol
Available as combination products
How is codeine metabolised to morphine?
Cap P450 2D6
10% caucasian population unable to convert
90% Chinese population unable to convert
What are the adverse effects of opioids?
Nausea and vomiting Constipation Sedation Respiratory depression Hypotension Urinary retention
What needs to be considered when initiating morphine?
Pain assessment, current analgesia
Determine opioid requirement (short acting preparation regularly plus PRN)
Convert total daily dose to MR formulation (i.e taken every 12 hrs)
What is breakthrough pain?
Transient exacerbation or recurrence of pain in patient who has mainly stable or adequately relieved background pain
End of dose failure
Incident pain
Spontaneous, unpredictable pain
10% total daily regular dose prescribed PRN
What needs to be considered when converting to an alternative opioid?
Determine 24 hr requirement
Use conversion factor for alternative opiate to determine new 24 hr requirement
Convert to appropriate dosage regimen
What are opioid equivalencies?
Morphine (po) 60mg
Hydromorphone (po) 9.8mg
Oxycodone (po) 30mg
Fentanyl (transdermal) 25 Microg/hr
What are IM opioids?
Prescribed 4 hourly
Takes several doses to achieve adequate levels
Variable absorption
Painful- SC route preferred
What drugs are used for patient controlled analgesia?
Morphine IV is the drug of choice (1mg bolus, 5 minute lock-out typical settings)
Tramadol, oxycodone or fentanyl if morphine allergy
What are the advantages of patient controlled analgesia?
Rapid analgesia once pain at steady state Ready prepared Patient satisfaction No dose delay Patient acceptability No peaks or troughs
What are the disadvantages of patient controlled analgesia?
Expensive
Requires IV access
Training
Monitoring
