Pain may be due to multiple causes so treat each pain appropriately.

Consider:

1. Cause of pain.
2. Anatomical site of pain e.g. bones, nerves.
3. Intensity of pain.
4. Emotional and spiritual factors - these may affect the pain threshold.
5. Previous response to medication.
6. Use of radiotherapy, chemotherapy, hormonal therapy, nerve block or TENS.
7. Complementary therapies.

• Reassess pain control regularly.
• Analgesics should always be given regularly using the oral route if possible.
• The rectal or subcutaneous route is acceptable when the oral route is not appropriate.  Other drugs and routes are available.  Please seek specialist advice from Pain Nurse (037), Macmillan nurse or pharmacist.
• Give regularly (PRN = Pain Relief Nil)

Visceral Or Soft Tissue Infiltration

(includes involvement of abdominal, pelvic and intrathoracic organs.)

To reduce inflammation, steroids or nonsteroidal anti-inflammatory drugs may be used.  Steroids may also be helpful in reducing tumour bulk.
In addition use analgesics by the step-wise approach. (as shown below)

Step - Wise Approach To Pain Control

		Step 3
		For Severe Pain Strong Opioid - Morphine Oral. Start At 10mq 4 Hourly NB. Start Lower If Not On Previous Analgesia
	Step 2
	For Moderate Pain E.G. Dihydrocodeine, Co-Proxamol / Co-Dydramol
Step 1
For Mild Pain Paracetamol 0.5-1g 4hrly Up to 4g daily

If an analgesic for mild pain fails, change to one analgesic for moderate pain.  If this fails, try a strong opioid.  May also consider prescribing other drugs "co-analgesics" for specific pains.

Dose Increases

• Dose should be increased until pain is relieved.  Suggested dose increases of '4 hourly' oral Morphine (not MST) as detailed below:
• 5mg -    10mg - 15mg - 20mg - 30mg - 40mg - 60mg - 80mg - 100mg - 120mg - 160mg - 200mg - 250mg - 300mg
• Convert to Slow Release Morphine (MST) when pain is controlled.

Breakthrough pain

1. If a patient has pain between 4 hourly doses of NON MST morphine, a further dose should be given stat.  This dose should be the SAME as the current 4 hourly dose.  The next due dose should then be the next increment on the scale
2. If a patient has pain between 12 hourly doses of MST, they should be prescribed the equivalent '4 hourly dose' in NON MST morphine (Oramorph or Sevredol) for’ breakthrough’ pain. e.g. MST 60mg BD at 8am and 8 pm + Sevredol or Oramorph PRN between.

With this dose of MST, the breakthrough pain dose is 20mg PRN of Oramorph.  The MST dose should then be increased after 24 hours taking into account the breakthrough doses given.

** IM or SC Diamorphine is three times as potent as oral Morphine.
    Therefore:    Oral Morphine 3mg = 1mg IM or SC Diamorphine

Alternatives to Morphine

Fentanyl Patches - may be suitable for patients who are stable on morphine but are experiencing problems (e.g. drowsiness, constipation, unable to take oral preparation).

Conversion from oral morphine to transdermal fentanyl

• Apply the Fentanyl patch at the same time as the last dose of MST (if converting to patches from Oramorph or Sevredol it may be necessary to give three further oral doses at four hour intervals while the drug builds up in the skin).
• A depot of fentanyl remains in the skin for up to 24 hours after patch removal.  Do not restart oral morphine for at least 12 hours after the patch is removed.
• Tramadol - may be considered for patients whose pain is not controlled on step 2 of the analgesic ladder who may not require step 3 analgesia. It has dual mechanism of action, part opioid and part enhancing serotoninergic and adrenergic pathways.  It is reported to have fewer opioid side effects (i.e. less constipation, respiratory depression). Dose orally: 50-100mg 4 hourly up to 400mg daily or 100-200mg twice daily of SR preparation.

Other Drugs Used To Control Specific Pains

Sometimes Referred To As "Co-Analgesics"

Bone Or Joint Pain

• Consider radiotherapy for malignant disease pain.
• Non-steroidal anti-inflammatory drugs.  These are more likely to be effective than opiates and can be used in combination with opiates.

Skeletal Muscle Spasm

Diazepam 2-15mg daily in divided doses, increased if necessary to 60mg daily.  Rectal diazepam solution is useful for spasm in the terminal stages.  Baclofen 5mg three times daily, gradually increased to a maximum of 100mg daily.

Nerve Pain

Compression:  
Consider radiotherapy otherwise; Dexamethasone often up to 16 mg.  Slowly reduce to maintenance of about 4mg. (last dose not later than 6 pm).
Infiltration &/or Compression:

1. Burning pain: Amitriptyline start on 25mg at night, titrate weekly
2. Stabbing pain: Carbamazepine start on 100mg TDS, titrate every 3-4 days.  This dose should be increased until either pain is controlled or maximum recommended dose (1600mg) is reached or unacceptable side effects occur.  Analgesic effects of tricyclics precede their antidepressant effect.  Sometimes it is necessary to use both antidepressants and anticonvulsants.  Gabapentin is an alternative anticonvulsant for the treatment of neuropathic pain.  Start with 300mg increase by 300mg daily until pain controlled or maximum of 1800mg per day.

Ketamine - useful for difficult neuropathic pain when used in sub anaesthetic doses. 10mg SC loading dose 120-150mg over 24 hours by SC infusion.
If ketamine is effective the morphine dose may need to be reduced by as much as 75% of the previous dose.

Side Effects Of Opiates

1. Nausea and vomiting
   Affects about 1/3 of all patients, but is transient and does not persist beyond 2 weeks.  Can be controlled with anti-emetics. e.g. Haloperidol 1.5mg BD or 3mg at night for 2 weeks.
2. Drowsiness
   Often a problem in the first few days
   If either of these effects is still present after 3 days, investigate other possible causes.
3. Constipation

A direct effect of opiates, so is ideally prevented by prophylactic regular use of a stimulant laxative with a softener. e.g.  Co-danthramer (danthron plus poloxamer) used within license.

Syringe Drivers (Subcutaneous)

Diamorphine 10 - 600mg+ (no maximum dose) per 24 hours is the drug of choice for subcutaneous continuous infusion over 12 or 24 hours.

Nausea and vomiting - 25% of patients require more than one antiemetic:

1. Haloperidol 2.5 - 10mg (also sedative - Usual dose 5mg)
2. Cyclizine 50 – 150mg 24hr-1
3. Metoclopramide 30 - 100mg 24hr-1
4. Ondansetron 4-8mg
5. (Methotrimeprazine 25 - 200mg) – use only with specialist advice

Anxiety and terminal restlessness

1. Haloperidol 5 – 15mg 24hr-1
2. Midazolam 20 - 100mg 24hr-1
3. Methotrimeprazine 50 - 200mg 24hr-1 (replaces other anti-emetics)
4. Consider diazepam rectal solution

Excessive secretions
Chest:        Hyoscine hydrobromide 0.6 – 2.4mg 24 hr-1 s/c infusion
Bowel:        Octreotide 0.3 - 0.6mg 24hr-1

Bowel spasm
Hyoscine butylbromide 20 – 60mg 24 hr-1 (will dry secretions to a lesser extent)

Bone pain and visceral pain
Ketorolac 60mg - 90mg 24hr-1 (may replace or reduce opiate need). All patients need prophylaxis for GI erosions eg.  H2 blocker – use omeprazole or lansoprazole IV, NOT ranitidine