W15 53 analgesics and pain management Flashcards
What are the types of pain?
Nociceptive - caused by (mechanical, thermal or chemical) stimulation of peripheral nerve fibres responding to stimuli approaching or exceeding harmful intensity
Neuropathic - caused by aberrant (abnormal) somatosensory activity due to damage or disease affecting the peripheral or central nervous system
Psychogenic - related to emotional state - made up
What are the possible targets for pain control?
Source of pain
Nociceptive substances eg PGs
Nerve transmitter substances eg serotonin
Modulators in spinal cord and brain eg morphine, opioid receptors part of the modulation
Emotional reaction to pain
What is the WHO pain ladder?
Step 1 - non-opioid, eg paracetamol
Step 2 - weak opioid, eg codeine, plus non opioid
Step 3 - strong opioid eg morphine, plus non opioid
What is good pharmacological control of pain post-procedure?
Post-op taking analgesics before LA has worn off can improve pain control
Regular administration times, eg every 6 hrs, will reduce breakthrough pain
Then PRN - pro-ray nata, as and when required
What is analgesia?
The absence of pain in response to stimulation which would normally be painful
What are adjuvant analgesics and give examples?
Medicines that are intended for indications other than the pain, but can also be used as analgesics in select circumstances (eg anticonvulsants and antidepressants).
What is the efficacy of different analgesic agents for pain relief?
Weak opioids may be less effective for odontogenic pain
Aspirin isn’t good for dental pain
A good combination = paracetamol and ibuprofen
What is a beneficial side effect of taking paracetamol in combo with ibuprofen?
Can have a beneficial antipyretic effect
(However this might mask post-opaerative signs of infection)
What are the facts about paracetamol?
Analgesic actions (potentially by inhibition of PGs in CNS)
Additional antipyretic action helpful in some dental conditions
NO anti-inflammatory action
Minimal interactions/adverse effects
Suitable for children (in correct dosing)
Used for mild/moderate pain alone or moderate/severe pain in combination therapy
What do NSAIDs do?
Inhibit prostaglandin synthesis (by inhibiting cyclo-oxygenase)
Anti-inflammatory activity leads to pain relief
What do COX 1 and 2 do?
COX-1 - constitutive protects gastric mucosa (try to avoid targeting)
COX-2 - inducible inflammatory, also renal (more targeted)
When should you restrict ibuprofen usage?
Restrict to less than 5 days in patients taking anti-hypertensive drugs
What odontogenic pain is good to be relieved by NSAIDs?
Inflammatory origin - eg pulpitis
Eg ibuprofen, diclofenac
Aspirin less appropriate due to risk of bleeding following extraction or other minor surgery
Which NSAIDs can you use in children?
Ibuprofen at smaller doses
Not diclofenac or aspirin
What NSAID drug-drug interactions are there?
Main issue is the risk of bleeding:
Potentiated by antiplatelets and anticoagulants
Increased risk of bleeding with SSRIs
What NSAID adverse effects are there?
Renal dysfunction
Gastro-intestinal side-effects (gastritis, bleeding)
Hypersensitivity reactions, eg rashes, angioedema, bronchospasm