DROWSINESS

At least 30% of patients with advanced cancer complain of drowsiness at times. A drowsy patient can be less distressing to the carers, but it is a mistake to think that drowsiness is a good thing for ill patients. Most patients dislike feeling drowsy and being unable to concentrate.

The main causes are:

1. Morphine

2. Psychotropic drugs

3. Hypercalcemia

4. Uremia

5. Hyponatremia

6. Infection

7. Advancing illness

1. If the patient is pain-free and drowsy, reduce the dose of morphine. The correct dose of morphine is the dose that relieves the pain without causing drowsiness. Morphine drowsiness is characteristically reversed by stimulation (conversation, for example). Some patients don’t mind this drowsiness. (“I don’t get so bored.”) If reducing the dose of morphine causes an increase in pain (and other pain-relieving drugs have been tried or considered) then this drowsiness due to morphine may very rarely have to be accepted.

If the pain is reduced (following palliative radiotherapy or a nerve block, for example) then the stimulating effect of pain (on general alertness and also on respiration) is lost. Morphine can then cause drowsiness, and in severe cases respiratory depression. (see Analgesics, Morphine)

2. Previously acceptable doses of psychotropic drugs may become too high, as renal or hepatic function deteriorates, or due to drug interactions. Reduce the dose of the psychotropic drug, and stop any unnecessary drugs. 

3. Hypercalcemia (calcium above 12.0mg/dL [3.0mmol/L]) can cause drowsiness (usually with nausea and thirst). (see Hypercalcemia)

4. Uremia can cause drowsiness (usually with confusion, nausea, hiccups and tremor). There is no treatment, but knowing the cause of the problem greatly improves management, and enables explanation to patient and family.

5. Hyponatremia (plasma sodium below 120mmol/L) can cause drowsiness. It can occur with adrenal metastases or in small (oat) cell carcinoma of the bronchus. It responds to fluid restriction. It is rare. (see Confusion)

6. Bacteremia or septicemia (from urinary tract infection or pressure sores) can present as drowsiness (sometimes with flushing or tachycardia). Steroids may prevent fever. An antibiotic may be indicated.

7. Increasing drowsiness is a feature of advanced disease. Patients sometimes fear that drowsiness means the beginning of the end. It helps to be optimistic as well as honest: “It is part of your illness, but your energy goes up and down when you are ill, and some days you need more rest than others.”

If drowsiness is distressing (if a patient wants to be more alert for a special occasion) then oral dextroamphetamine 2.5mg to 5mg per day can sometimes be helpful as a short term measure. There is risk of agitation.

The author and publisher have taken precautions to ensure that the information in this book is error-free. However, readers must be guided by their own personal and professional standards of good practice in evaluating and applying recommendations made herein. The contents of this book represent the views and experience of the author, and not necessarily those of the publisher.