Nausea and vomiting are common symptoms in people with cancer and may be caused by the disease itself or by certain cancer treatments. In addition to chemotherapy, they may also result from radiotherapy, some targeted therapies, immunotherapy, certain pain medications (particularly opioids), and other medical conditions such as digestive, metabolic or neurological disorders.

Nausea and vomiting may occur:

  • Within the first 24 hours after treatment (acute nausea and vomiting).
  • Between 1 and 7 days after treatment (delayed nausea and vomiting).
  • Before treatment is administered, as a learned response based on previous experiences (anticipatory nausea and vomiting).

Treatment

Effective treatments are available to prevent and control nausea and vomiting associated with cancer and its treatments. The medicines used are known as antiemetics and are selected according to the likelihood that a treatment will cause these symptoms, as well as the individual characteristics of the patient.

Antiemetics may be administered in several forms:

  • Tablets or capsules.
  • Intravenous injections or infusions.
  • Suppositories.
  • Subcutaneous formulations.
  • Transdermal patches in selected situations.

When a treatment is known to carry a moderate or high risk of causing nausea and vomiting, antiemetics are usually given preventively before treatment begins and, in some cases, continued for several days afterwards to help prevent symptoms from developing.

Possible Side Effects of Antiemetics

Side effects vary depending on the medication used, but may include:

  • Constipation.
  • Headache.
  • Drowsiness or fatigue.
  • Dizziness.
  • Dry mouth.

Inform your healthcare team if you experience side effects or if your nausea and vomiting are not adequately controlled, as your treatment may need to be adjusted.

Helpful Self-Care Measures

In addition to prescribed medication, the following strategies may help:

  • Eat small amounts of food several times a day rather than having large meals.
  • Drink fluids in small amounts and frequently to help prevent dehydration.
  • Avoid fatty, fried or highly seasoned foods if they worsen your symptoms.
  • Avoid strong food smells or environmental odours that trigger nausea.
  • Choose cold or room-temperature foods if cooking smells are unpleasant.
  • Maintain good oral hygiene.
  • Rest after meals, but avoid lying completely flat.

Relaxation techniques and psychological support may also be beneficial when anxiety contributes to nausea or treatment-related distress.