Nausea and Vomitting

Cancer, or its treatments, can sometimes cause nausea (feelings of sickness) or vomiting (being sick), which can be unpleasant and distressing. There are various ways of preventing or reducing nausea and vomiting and they are discussed here. Information is given about the medicines, which are commonly used to treat nausea and vomiting - these are known as anti-sickness drugs (or anti-emetics). It also contains other ideas to help you cope. 

Causes and Risk Factors

The mechanisms by which a person feels sick or vomits are complicated. Within the body, nausea and vomiting is controlled by an area of the brain known as the vomiting centre. This area may be stimulated to cause nausea or vomiting by nerves within the gut (stomach) or by other parts of the brain. Psychological factors can also influence whether a person feels sick.

The reasons why someone with cancer may experience nausea and vomiting are listed below:

• Treatments

• Chemotherapy. Some types of chemotherapy can affect the vomiting centre and cause nausea and vomiting.

• Radiotherapy. Radiotherapy to the brain, stomach, bowel, or close to the liver may lead to nausea and vomiting.

• Hormonal therapies occasionally cause nausea.

• Morphine based medicines used as painkillers. Some of these drugs can affect the vomiting centre.

• Physical reasons

• Changes in the body chemistry such as high levels of calcium in the blood or a raised pressure within the brain can also affect the vomiting centre.

• Damage to the liver. If the liver is not working properly, waste products can build up in the blood and these can lead to nausea and vomiting.

• Some types of cancer can cause blockage of the bowel, especially cancers, which affect the pelvis or abdomen.

• Constipation.

The type of anti-sickness treatment you receive will depend on the cause. Sometimes there is more than one cause of nausea and vomiting and more than one type of treatment may be needed. The drugs also work in different ways and can often be used together to achieve the best effect.

Diagnosis and Screening

You will have nausea (feelings of sickness) or vomiting (being sick) while you are receiving your treatment. Always be sure to tell your doctor or nurse if you are experiencing that for more than a day.

Management

Many different types of drugs are used to control nausea and vomiting. Some of these work on the brain by preventing the stimulation of the vomiting centre. Others work on the gut by speeding up the rate at which the stomach empties, and moving food through the intestines more quickly. The most effective way of controlling nausea and vomiting is by treating the cause, if possible.

How the drugs are given?
Anti-emetic drugs can be given in a number of ways:

• By mouth - the tablets are swallowed with plenty of water.

• Into a vein by drip - the anti-emetics can be made into a fluid and given into a vein (intravenously) through a small tube (cannula) inserted into the vein.

• Into the muscle - the drugs are given by injection into a muscle (intramuscular injection).

• Into the fatty tissue under the skin (subcutaneously) - the drugs are either injected using a syringe, or given slowly over several hours using a pump attached to a small needle that is placed just under the skin.

• Suppositories - these are put into the back passage (rectum) where they dissolve and are absorbed into the bloodstream through the lining of the gut.

Some cancer treatments, such as particular chemotherapy drugs, are known to cause nausea and vomiting. In this situation anti-emetic therapy will be given before the treatment has started. The anti-emetic drugs may also be continued for a few days after the treatment has finished.

When someone feels sick or nauseous due to the cancer itself it can take a while to control this distressing symptom. You will be given anti-emetics and, if possible, the cause of the sickness will be treated.

Whatever the cause of the sickness, the anti-emetics should be taken regularly so that the sickness does not have a chance to come back. If you have any nausea or vomiting which is new, becomes worse, or lasts more than few days let your doctor or nurse know.

Common anti-emetics
Some of the more common drugs which may be prescribed are:
Metroclopramide (Maxalon)
Domperidone (Motilium)
Haloperidol (Serenace)
Cyclizine (Valoid)
Ondansetron (Zofran)
Granisetron (Kytril)
Lorazepam (Ativan)
Prochlorperazine (Stemetil)
Dexamethasone
Levomepromazine (Nozinan)
Tropisetron (Navoban)

Possible side effects

Sometimes anti-sickness drugs may cause side effects. Different drugs will have different side effects and each person may react in a different way. Some of the more common effects are listed below alongside the drugs that may cause them

• Constipation. Granisetron, ondansetron and tropisetron can all cause constipation. This can usually be relieved by drinking plenty of fluids, eating a high fibre diet and doing gentle exercise. Sometimes you may need to take laxatives to stimulate your bowel. These can be prescribed by your doctor.

• Headaches. Granisetron, ondansetron and tropisetron can all cause headaches. Let your doctor know if you are having headaches while receiving one of these drugs as part of your anti-emetic therapy.

• Flushing. Ondansetron, tropisetron (and dexamethasone when injected) can cause flushing, or a sensation of warmth. Although this is rare tell your doctor if you experience these side effects.

• Tiredness and feelings of weakness (fatigue). Cyclizine, haloperidol, levopromazine and lorazepam may cause drowsiness in some people. It is important to allow yourself plenty of time to rest, especially if you are receiving chemotherapy or radiotherapy as part of your treatment

• Indigestion. Indigestion can be caused by dexamethasone. Tell your doctor if this is a problem for you as medicines can be prescribed to help.

• Wakefulness (insomnia). Dexamethasone may interfere with going to sleep. This problem may be reduced by taking your last dose of the day in the afternoon, rather than late in the evening or last thing at night.

• Twitching. Metoclopramide may cause muscle twitching, especially in children and young adults. Tell your doctor if this is a problem, as other medicines may suit you better.

You can also try the following:

• Eat several small meals throughout the day rather than a few large ones.
• Stay away from fatty, sweet, or fried foods.
• Eat foods cold or at room temperature.
• Eat dry foods like cereal, toast, or crackers in the morning.
• Wear loose clothes.