GENERAL QUESTIONS ABOUT MORPHINE

by Dr Robert Twycross MA DM FRCP, Macmillan Clinical Reader in Palliative Medicine, University of Oxford
Dr Sylvia Lack, Consultant in Hospice Care, Waterbury, Connecticut

I am well-controlled on the present dose of morphine, but once or twice a week the pain breaks through again. Is there anything I can do about this?

Occasional 'breakthrough' pain is experienced by some patients. It possibly relates to increased activity or tiredness, or may come completely 'out of the blue'. If you experience breakthrough pain, a supplemental dose of morphine solution or standard tablets should be taken. Because an immediate effect is necessary, long-acting tablets are not ideal in this situation.

The supplemental dose will normally be the same as the 'every 4 hours' dose, or roughly one-third of the 'every 12 hours' dose of long-acting tablets. If breakthrough pain is experienced between most or all regular doses, it probably means that the regular dose needs to be increased. You should not do this by yourself, but seek direction from your doctor or nurse.

Why morphine? I thought that was for pain, but my problem is shortness of breath.

If your breathing has become very rapid because of cancer affecting the lungs, morphine often helps by slowing the rate of breathing down. This makes you feel more comfortable. You are also less likely to end up gasping for breath when you get up and do things.

The reason morphine is often of benefit in this situation is that many of the extra breaths you are taking are not necessary for your system. An over-rapid rate of breathing tends to become inefficient. Slower and deeper breaths are of greater benefit.

The dose of morphine to reduce shortness of breath is usually smaller than those used to relieve pain. As always, the benefits must be weighed against the unwanted effects. The aim of the morphine is to make you less short of breath and more relaxed. But, as with pain, morphine is not the cure-all for shortness of breath. If the shortness of breath relates to a second disorder such as asthma, bronchitis or heart failure, treatments other than morphine are more appropriate.

Is oral morphine really effective?

Yes. It is only rarely necessary to prescribe morphine by injection because oral morphine is not working.

Is it necessary to give more morphine by mouth than by injection?

Yes. As a general rule, the dose of morphine should be doubled when changing to the oral route. Occasionally it is necessary to increase this to three times the previously injected dose.

Wouldn't injections be better?

No. Oral medication results in a more constant drug level in the body. This leads to better pain relief and fewer unwanted effects. Injections also tend to tie you to a second person unless you give your own.

Are injections ever needed?

Yes. Injections are necessary if you are:

• Vomiting a lot
• Unable to swallow

Once the vomiting has been controlled using an anti-vomiting drug also by injection), it is often possible to go back to giving the medicines by mouth.

Once on injections, is it possible to change successfully to the oral route?

Yes, though it is often wise to convert to the oral route in stages. For example, the anti-vomiting drug can be changed first, followed the next day by the 10 a.m. and 6 p.m. dose of morphine. Finally, the other doses can be changed. The 'run-in' period with the other medication gives guidance as to whether oral administration is going to be successful.

A progressive conversion may also be necessary if you find it difficult to believe that oral medication will be as effective.

Can morphine be given by suppository?

Yes. Morphine suppositories are available in a range of strengths. They can also be made by a helpful pharmacist. The same amount is needed in suppositories as by mouth to control pain. Suppositories are a useful alternative to injections, particularly in the home.

Why do some people need more morphine than others?

There are many reasons why this is so. These include:

• The cause of your pain.
• Differences in the severity of pain.
• Differences in sensitivity to pain.
• Differences in how the body uses morphine.
• Whether other pain relief drugs and/or non-drug treatments are also being used.
• The presence or absence of other symptoms.

Why do they create such a fuss about giving morphine in hospital? If there is only one registered nurse on duty, I often have to wait ages until one comes from the next ward.

The apparent fuss relates to legal requirements. Certain drugs, morphine included, are 'scheduled' or 'controlled'. This means double-checking and more careful book-keeping - hence the second nurse. The idea behind the regulations is to prevent drugs which are attractive to addicts from getting into the wrong hands. The regulations are not intended to prevent cancer patients from receiving an adequate quantity of morphine. It is obviously upsetting if a shortage of nurses has this effect.