Analgesic Ladder
- Paracetamol
- Analgesia
- Antipyretic (PGE1) on thalamic temperature centre
- Liver injury (normally metabolised by P450 and NABQI) if metabolism becomes "super saturated"
- ?Inhibit prostaglanding production
- Effects
- Antidote: N-acetylecysteine (donates suphydryl groups to form protective glutathione)
- NSAIDs
- GI: Inhibit PGE2 + direct effect - dyspepsia, gastritis
- Renal: ARF - inhibition of PGI2 and PGE2 formation that occurs during situations of reduced renal perfusion (PGs normally produce vasodilation)
- Coagulation: Inhibit TXA2 - reduced ability of platelets to aggregate to form platelet plug, permanent effect (only overcome by production of new platelets)
- Bronchospasm: Increased production of Leukotrienes
- Inhibit COX (reduce inflammatory pain-inducing prostaglandins) on arachidonic acid (from Membrane Phospholipids and Phospholipase A2/Lipocortin)
- Effects
- Opiates
- Analgesia - moderate/severe pain
- Respiratory depression
- Antitussive (cough depression)
- Sedation
- Nausea / vomiting - stimulation of chemotactic trigger zone
- Constipation
- Euphoria
- Histamine release - mast cells: pruritis
- Increased tone of sphincters (esp sphincter of Oddi - stim contraction of GB; can exacerbate biliary pain)
- MOA: Effects on Mu and Kappa receptors
- Effects
- Antidotes: - Naloxone (mu receptor antagonist)
- Local anaesthetics
- 3-in-1 block (latcut/femoral/obturator) for #NOF
- Intercostal blocks for #ribs
- In epidural (extradural space)
- "float" combination of LA + opiate - normally 0.25% bupivacaine + morphine
- Used post-operatively for pain; thoracic / upper abdominal surgery
- Contraindications - coagulopathy, local sepsis, hypovolaemia (risk of profound hypotension)
- Local nerve blocks:
- Caudal block
- Epidurals
- Para/Spinal block
- Antidepressants
- Neurotransmitter modulators - GABA / carbemazepine
Complementary
- Hypnosis
- Cogntive therapy
- Acupuncture