Palliative care: Nausea and vomiting

Last updated: Thursday, January 21, 2016

As with pain, there are many causes of nausea and vomiting (e.g. constipation, severe pain, hypercalcaemia, intestinal obstruction, drugs). It is important to identify the most likely cause as this determines the treatment.

At least four different neurotransmitter receptors have been isolated in the areas of the brain that regulate vomiting. Antiemetics can be categorised according to their pharmacological group, effect on a specific neurotransmitter, or likely site of action.

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When initiating an antiemetic, the patient should be reviewed every 24 hrs; it may be necessary to substitute the antiemetic or add in another drug from a different class (e.g. haloperidol and cyclizine work in different ways). A single drug is normally sufficient to control symptoms but using two drugs from different groups may be required in resistant patients. Remember to think laterally when using combination antiemetic therapy; don’t use drugs that may antagonise one another (e.g. cyclizine inhibits the prokinetic actions of metoclopramide). Adjuvant agents such as corticosteroids may be helpful.

The oral route is suitable for prophylaxis where there is mild nausea and vomiting; non-oral routes should be used for moderate to severe symptoms.

In practice cyclizine, haloperidol or a prokinetic such as metoclopramide or domperidone are often used as first-line antiemetics. Levomepromazine is also used as an antiemetic in palliative care. You do need to be careful about the contraindications to each antiemetic, and assess their relevance to the individual patient.