Moderate to Severe Pain

First line treatment:

  1. Opioid
  2. Plus co-analgesic/adjuvant drug if indicated.

Opioids

Opioid analgesics are used to treat moderate to severe pain; they diminish both the sensation and affective response to pain.

NB: "The initiation of an opioid requires cautious adjustment and frequent review because individuals vary markedly in their response. Best practice … is to start with a low dose and slowly adjust the dose until it controls the patient’s pain. The initial opioid dose is determined by the previous medication used and the severity of the pain. Ensure the patient and their carers know who to contact if there are unexpected problems or concerns." (Therapeutic Guidelines: Palliative Care, 2016, p. 209).

Opioid preparations may be available as:

  • immediate release
  • modified release

Modified release preparations should never be crushed or chewed as this can result in a large dose being absorbed over a short period.

See the Dose Conversion tables for converting from other opioids to an equianalgesic dose of oral morphine, or converting from oral morphine to equianalgesic doses of other opioids.

Neuropathic pain

Patients experiencing pain related to cancer may have an element of neuropathic pain, which responds only partially to opioids.

Determining whether pain is neuropathic

Does the patient describe their pain in this way?

  • Pins and needles, tingling, burning, lancinating, shooting
  • Allodynia (pain caused by a stimulus that does not usually cause pain)
  • Pain in missing body part
  • Pain in a numb area

Any or all of these symptoms suggest neuropathic pain related to nerve involvement. Because neuropathic pain may respond only partially to opioids, the use of co-analgesic or adjuvant drugs such as antiepileptic drugs or antidepressants may be necessary.

Antiepileptic drugs

First preference

Pregabalin 25 mg nocte, increasing slowly to a maximum of 600 mg/day (caution in renal impairment)

Other options

Consult palliative care team in each case

  • gabapentin
  • carbamazepine
  • clonazepam 0.5 mg orally/subcutaneously/sublingually, twice daily, increasing to maximum of 2 mg twice daily.

Antidepressant drugs

Either:

  • amitriptyline 10-25 mg orally, at night, increasing every 7 days to a usual maximum dose of 75 mg at night
  • nortriptyline 10-25 mg orally, at night, increasing every 7 days to a usual maximum dose of 75 mg at night
  • duloxetine 30 mg orally, daily

For specific suggestions regarding starting doses of co-analgesics, contact your local palliative care team.

Second line treatment

Where pain is not adequately controlled, consider the following:

How many breakthrough (BT) doses has the patient required in the last 24 hours? If more than 2-3 doses in 24 hours, the regular daily dose of opioid may need to be adjusted by adding the total BT doses per 24 hours to the daily dose, up to a 50% increase in the daily dose.

NB: Increase the dose in this way no more often than every 2-3 days.

If not already treating for neuropathic pain, consider whether that might be an issue.

Gradually increase the dose of the co-analgesic drug/s according to recommendations for antiepileptics or antidepressants.

Types of pain

Nociceptive superficial somatic pain

If the patient describes their pain as:

  • sharp
  • stinging
  • hot

Think nociceptive superficial somatic pain e.g. from malignant ulcers or stomatitis

Use: opioids

Nociceptive deep somatic pain

Described as dull, throbbing, aching

May relate to:

  • liver capsule distension – use corticosteroids
  • bone metastases

Visceral nociceptive pain

Does the patient describe their pain as:

  • cramping or colicky
  • dull, referred pain

Symptoms indicate visceral nociceptive pain.

Use:

  • opioids, plus

    • antispasmodics if colicky pain
    • paracetamol, corticosteroids if constant pain

Skeletal muscle spasm pain

Use:

  • diazepam 2-5 mg orally up to three times daily
  • baclofen 5 mg orally, 3 times daily, increasing every 3 days to 10-25 mg orally, 3 times daily

Smooth muscle spasm pain

Hyoscine hydrobromide or hyoscine butylbromide may be used with opioids for cramping pain related to bowel obstruction.

Use either:

hyoscine hydrobromide

  • 0.4 mg SC, 4-hourly or
  • up to 1.6 mg/24 hours via continuous subcutaneous infusion (CSCI)

hyoscine butylbromide

  • 10-20 mg SC, 4 hourly or
  • 60-80 mg/24 hours initially by CSCI; titrate to effect to maximum of 120 mg/24 hours