Principles of the WHO ladder

♦ Strength of analgesic chosen (i.e. step of ladder) depends on severity of pain, not stage of disease.

♦ Adjuvant analgesic is chosen according to cause and type of pain.

♦ Opioids should generally be used in combination with non-opioids.

The WHO analgesic 'ladder'. (Reproduced with permission.)

The prototype analgesics for each step of the analgesic ladder are:

♦ Step 1: paracetamol or non-steroidal anti-inflammatory drug

♦ Step 2: codeine or dextropropoxyphene + paracetamol or NSAID.

♦ Step 3: morphine or diamorphine + paracetamol or NSAID. Opioids should be prescribed at regular intervals. Therapeutic doses should be given and codeine preparations with sub-therapeutic doses of codeine (<30 mg) should be avoided (e.g. codydramol, cocodamol, cocodaprin).

Prescribed doses and indications for the common adjuvant analgesics are listed in the table. There is evidence for the tricyclic anti-depressants and carbamazepine in neuropathic pain but the former generally have fewer side-effects and should usually be used first.

There is strong evidence for the effectiveness of NSAIDs as analgesics; however, their use will depend on the individual risk:benefit ratio. Those at high risk of side-effects are:

♦ past history of peptic ulcer

♦ concomitant steroid use

Table 14.1 Adjuvant analgesics (drugs with a primary indication other than pain)

Drug

Dosage

Indications

Side-effects

NSAIDs e.g. ibuprofen, diclofenac naproxen

See prescribing information for specific guidance

Bone metastases; soft tissue infiltration; liver pain

Gastric irritation; fluid retention; headache; vertigo; caution in renal impairment

Steroids e.g. dexamethasone

4-16 mg/day po, sc, iv

Raised intracranial pressure; nerve compression; soft tissue infiltration; liver pain

Gastric irritation if together with NSAID; fluid retention; confusion; Cushingoid appearance

Amitriptyline

25 mg nocte (starting dose) Titrate according to response and tolerability

Nerve pain—any type

Sedation; dizziness; dry mouth; constipation; urinary retention

Carbamazepine

200 mg nocte (starting dose) Titrate according to response and tolerability

Nerve pain—any type

Vertigo; constipation; rash

There is no evidence as yet of the superiority of the selective Cox 2 inhibitors available. Sulindac has been favoured for patients with renal impairment needing a NSAID.

0 0

Post a comment