WHO Pain Ladder

From: Helen Dynda (olddad66@runestone.net)
Sat Jul 14 00:03:20 2001


[]]] WHO Pain Ladder

http://www.home.eznet.net/~webtent/pain-who-ladder.html

1.) Mild Pain

Mild pain is usually treated with over-the-counter (OTC) analgesics such as aspirin, ibuprofen, and acetaminophen. These agents have some effects in the central nervous system, but mainly exert their analgesic effect in the periphery.

2.) Mild to Moderate Pain

For mild-to-moderate pain, the WHO analgesic ladder advocates the use of weak opioids either alone or in conjunction with OTC analgesics. These may be used alongside adjunctive therapy such as acupuncture, transcutaneous electrical nerve stimulation, and steroids (e.g, dexamethasone). Examples of weak opioids used are:

Propoxyphene: Dextropropoxyphene is a mild opioid analgesic. It is about one half to two thirds as potent as codeine and can be combined with paracetamol to give a greater analgesic effect than paracetamol alone. The use of dextropropoxyphene is associated with the usual side effects of opioid use: nausea, constipation, abdominal pain and drowsiness.

Dihydrocodeine and codeine: Dihydrocodeine and codeine have very similar actions pharmacologically. They may often be combined with paracetamol or aspirin for added analgesia. The low content of the weak opioid in these preparations means that they are usually only effective in mild to moderate pain.

Dihydrocodeine and codeine have anti-tussive effects and their side effect profile is similar to that of other opioid drugs (see above). Codeine in particular is often associated with constipation. In such instances, the prophylactic use of laxatives is recommended, rather than being withheld until constipation develops.

If a greater analgesic effect is required, proprietary fixed-dose combinations, which have a greater dose of weak opioid than the standard formulations are employed. However, towards the top end of the moderate pain scale, fixed dose combinations may be less suitable because of the risk in exceeding the maximum daily dose requirements. In such cases, it may be better to use codeine, dihydrocodeine or tramadol separately, adding in an OTC analgesic such as ibuprofen as a single ingredient.

3.) Moderate to Severe Pain

The third step of the WHO analgesic ladder suggests that strong opioids, used either alone or with adjunctive therapy will provide optimum control of pain. Strong opioids such as morphine, diamorphine, fentanyl and methadone may be used for most forms of severe continuous pain, such as cancer pain (see below). Long term use in musculoskeletal pain should be avoided.

Strong opioids may also be significantly less effective in neuropathic pain. Often, intermittent pain does not respond well.

These agents are obtained from the unripe seed capsules of the poppy plant, Papaver somniferum. The milky juice derived is then dried and powdered to make opium. This is one of the oldest analgesics known to man.

Methadone: Methadone is an effective analgesic. It has a long half-life, and therefore has an extended duration of action. As an analgesic it can be used for occasional use in patients who have severe chronic pain that is non-responsive to morphine. Regular users, or abusers may require larger doses than normal for acute painful episodes. Methadone is also used in dependent individuals who are suffering from physical withdrawal symptoms. Marked sedation can be seen in some patients. Effects on cough and bowel motility are qualitatively the same as those seen with morphine.

Morphine: Morphine is the most commonly used of the strong opioids. It is particularly suitable for severe continuous pain, whether this be visceral or of soft-tissue origin.

Doses are titrated, with patients starting on a relatively low dose, which can then be increased depending on the level of pain control achieved. It is important that doses are given 'round the clock' and not until the patient actually experiences pain. If there is breakthrough pain, immediate release preparations are usually administered. As long as with each incremental dose an incremental dose in analgesia is achieved, then it remains possible to continue to titrate upwards in order to achieve maximal pain control. However, patients on morphine will probably suffer from some degree of constipation, which can be quite severe in some cases. Therefore, laxatives are often prescribed prophylactically from the start of morphine therapy. Other unwanted adverse events are respiratory depression, nausea, vomiting, mental clouding and dizziness.

Last updated: 1/1/2001.


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