The use of morphine in nursing homes

Contents

Morphine to relieve dyspnoea
Morphine as a sedative
Morphine for arthritic pain
Morphine for ischaemic pain
Morphine misuse

A great deal of experience has now been gained by GPs in the use of morphine for treating patients with cancer. It is not surprising that GPs can now see many possible uses for morphine in patients with non-cancer terminal disease such as end stage cardiac, respiratory or renal failure. There are also patients with severe and chronic pain due to ischaemia of a limb from inoperable peripheral vascular disease, arthritis, spinal crush fractures, etc.

Morphine to relieve dyspnoea

In addition to being a potent analgesic, morphine has other useful properties that may be useful in nursing home practice. For instance, the well-known effects of opioids causing respiratory depression combined with reducing pain and anxiety, have resulted in its role for relieving dyspnoea in patients with terminal repiratory failure from whatever cause. Small doses from 2.5mgm to 10mgm of morphine syrup fourth hourly are all that is usually needed. Some clinicians favour the use of nebulised morphine but there is little evidence to show that this route is superior to the oral route. The subcutaneous route can be used for those patients who are unable to swallow.

Morphine as a sedative

Morphine has well-known sedative effects as well as some euphoric effects and as a result is used in the management of terminal disease. However, it should be pointed out that there are much better sedatives such as the benzodiazepines for these situations.

Clonazepam for example is easy to give by the oral, sublingual or subcutaneous route. It is usually given 12 hourly in doses from 0.5mgm to 2mgm.

Midazolam given subcutaneously is useful for emergencies such as fitting and severe restlessness and agitation - the usual dose is 2.5mgm to 5mgm. Its effects usually only last for about three hours.

Occasionally a major tranquillizer is needed particularly for delerium. It is not advisable to use morphine primarily for its sedative effect.

The other caution with the use of morphine in terminal therapy is the problem of morphine toxicity where morphine given in doses that are too high can cause drowsiness, restlessness, confusion, agitation and myoclonic jerks etc. This is a particular risk with the build up of morphine seen as renal function diminishes during a terminal illness. Morphine dose and administration intervals need to be adjusted in these situations.

Morphine for arthritic pain

There are some patients who are unable to tolerate NSAIDs and in whom paracetamol in maximal doses does not control the pain. An opioid may be considered starting with codeine related drugs and allowing for the inevitable constipation. In more severe cases the judicious use of morphine, in particular for severe night pain, can be helpful, with care not to use doses that cause confusion. Usually 2.5mgm to 10mgm will be enough.

Morphine for ischaemic pain

One of the great challenges in the control of severe pain seen in nursing homes is the pain associated with ischaemia. It is often a situation where amputation is out of the question in a patient with an ischaemic leg, because of patient and/or family refusal, or because the clinical condition is too poor for anaesthesia.

Morphine is of some but limited use for severe ischaemic pain. Peripheral vasodilators are also of some use. An old drug well known to anaesthetists is ketamine. Ketamine activates the limbic system and depresses the cerebral cortex producing profound analgesia, slight respiratory depression, cardiovascular stimulation and amnesia. The protective reflexes are maintained. When simple touch leads to intense and prolonged pain resistant to other analgesics, ketamine may be considered. Use of ketamine will be discussed in a later article.

Morphine misuse

It is illogical to use morphine just because a patient's condition is terminal. As described above it is not a good sedative. There needs to be a strong indication to use such a powerful drug and the dose always needs to be carefully titrated in the elderly frail patient. Morphine has some very valuable roles in some acute situations in nursing homes but is rarely needed long term. More research is needed to more clearly define the rational use of morphine in nursing homes.

Dr Andrew Binns, Director Palliative Care, St Vincent's Hospital, Lismore, NSW, Australia.
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