Other analgesics and adjuvant therapies

Entonox

• • 50:50 mixture of nitrous oxide and oxygen
  • Provides effective inhalational analgesia
  • Patient able to self-administer and control the mouthpiece
  • Useful in the ED, pre-hospital care, labour analgesia and for procedural analgesia.
  • In some settings it may be used without a medical prescription, by appropriately trained staff. E.g. Labour suite.

Contraindications:

• • • Pneumothorax
    • Bowel obstructions
    • Visceral perforations
    • Decompression sickness
    • Head injury
    • Middle/inner ear injury

Ketamine

• • Potent NDMA receptor antagonist and some modulation at opioid receptors.
  • Given by IV infusion by specialists
    • Prescribed on the “continuous infusion” section of TPAR.
    • Prepared as 5 mg/mL
    • Rate of infusion between 1-3ml/hour (5-15mg/hour)
  • Useful in both nociceptive and neuropathic pain
  • Should be supervised by specialists – pain team and anaesthetists.
  • May also be given orally.

Contraindications:

• • • Raised intracranial pressure
    • Ischaemic heart disease
    • Mental illness, delirium and/or hallucinations
    • Pregnancy and breast feeding
    • Glaucoma

Consider adjunctive therapies if appropriate.

Gastrointestinal or Biliary Spasm:

Hyoscine butylbromide (Buscopan®) 20mg IM or Slow IV, repeated after 30 minutes if necessary (Oral dose 20mg QDS)

Skeletal muscle spasm, short course of either:

• • Benzodiazepines e.g. diazepam.
  • Baclofen

Pain from skeletal metastasis (specialist therapies):

• • Bisphosphonates (IV Pamidronate up to 90mg once, every 4 weeks) – caution in impaired renal function and consider dose reduction
  • Radiotherapy
  • Strontium