Pain Management
Medication
There are a large number of drugs that are widely used for the control of pain:
Paracetamol
For people with mild or moderate pain, paracetamol may prove sufficient for pain control. Often undervalued, paracetamol is a highly effective analgesic, with no gastrointestinal adverse effects, and is available in a variety of formulations, including in combination with codeine.1 Although side effects are rare, paracetamol should be used with caution in patients with hepatic or renal impairment, and in those with alcohol dependence. Overdosage with paracetamol is particularly dangerous.2
Non-steroidal anti-inflammatory drugs (NSAIDs)
NSAIDs have a threefold action: relieving pain, reducing inflammation and reducing fever. They can be particularly useful in conditions where the pain is accompanied by inflammation, such as rheumatoid arthritis. They can cause serious side effects such as stomach ulcers or kidney failure.
Opioids
The strongest of all analgesics used today are opioids3. Opioid drugs are traditionally used for patients with more severe pain. They vary from weak opioids such as codeine and propoxyphene, to the stronger drugs such as morphine or oxycodone. Strong opioids should be considered when other options have failed to control a patient’s pain; patients should not be continued on a less effective drug when an opioid could significantly improve their pain management.
Analgesics are the mainstay of therapy for patients with persistent chronic pain and, according to the WHO Guidelines,4 they should be administered:
- by the clock;
- by mouth;
- by the ladder;
- for the individual;
- with attention to detail.
By the clock
Analgesics should be administered at regular dosing intervals (e.g. every 12 hours) and not on an ‘as required’ basis. ‘As required’ administration of opioids may result in the patient losing pain control earlier than expected, with their carer being unwilling to give another dose so soon. When the patient finally receives treatment, they may need a large dose, which increases the likelihood of side effects.5
By mouth
The WHO recommends that the oral route should be used whenever possible.4 This route is simple, convenient and economical when compared with other routes of administration, such as subcutaneous (s.c.) delivery using syringe drivers. Oral opioids are as effective as parenteral opioids in most circumstances, given appropriate dosage adjustment, and can control the pain of most patients with advanced cancer.6-7Oral analgesics also allow patients to avoid having painful injections, and maintain their independence and mobility.
Analgesics should always be prescribed at the dose needed to maintain pain control. The goal is to achieve optimal pain control with no, or tolerable side effects. This requires constant evaluation of the individual patient’s needs, careful titration, and control of breakthrough and incident pain using IR analgesics.
The WHO analgesic ladder (see the figure below) is designed to help physicians treat patients’ pain effectively and in a stepwise fashion. The WHO advocates the use of non-opioids at Step 1, followed by opioid analgesics at Step 2 for mild to moderate pain and at Step 3 for moderate to severe pain. If weak opioids have failed to provide adequate pain control, the patient should be started on a strong opioid as there is no benefit in switching between weak opioids.8 Adjuvant analgesics, such as corticosteroids and antidepressants, can be used at any step of the ladder.
For the individual
There are no standard doses for opioids. The WHO states that the ‘right’ dose is that needed to relieve the patient’s pain.4
With attention to detail
The WHO recommends that doctors write out the patient’s drug regimen in full, including the name of the drug, the reason for use, the dose and the number of times per day.4 The patient should also be warned about possible side effects.
References:
1) Chronic pain and its impact. Research study conducted for Action on Pain, funded by Pharmacia Ltd and Pfizer Ltd. London: MORI Social Research Institute, 2001.
2) British National Formulary No. 52 p. 221.
3)British Pain Society guidelines for the use of opioids in non-malignant pain. Available from: URL: http://www.britishpainsociety.org/.
4) World Health Organization. Cancer pain relief with a guide to opioid availability. 2nd ed. Geneva: The Organization; 1996.
5) Melzack R. The tragedy of needless pain. Sci Am 1990; 262:19-25.
6) Rane A, Säwe J, Dahlström B, et al. Pharmacological treatment of cancer pain with special reference to the oral use of morphine. Acta Anesthesiol Scand 1982; (suppl 74):97-103.
7) Twycross RG. Clinical experience with diamorphine in advanced malignant disease. Int J Clin Pharmacol 1974; 9:184-98.
8) Regnard CFB, Tempest S. A guide to symptom relief in advanced disease. 4th ed. Cheshire: Hochland and Hochland; 1998. p.18.