Nausea and Vomiting

Many people are concerned that cancer treatment will make them feel sick to their stomach (nausea) or cause them to throw up (vomit). Nausea and vomiting commonly occur together. About one half of people treated for cancer will have nausea and vomiting. Today, there are many new and effective medications available to help control these side effects.

The process that leads to nausea and vomiting is complicated. Nausea and vomiting are believed to be controlled by an area of the brain called the vomiting centre. This area may become stimulated by nerves within certain parts of the esophagus, stomach or bowel (intestines) that become irritated. It could also be stimulated by other parts of the brain.

Types

Acute nausea or vomiting

Usually occurs several minutes to a few hours after treatment is given and often goes away within the first 24 hours.

Delayed vomiting

Develops more than 24 hours after treatment is given and can last for 6 to 7 days.

Anticipatory nausea or vomiting

After a person has had a few treatments, they may feel nauseated before treatment, because they are anxious and expect to be sick. They connect certain sights, sounds or smells with treatment and feel nauseated when these are experienced. This is more common in people receiving chemotherapy.

Causes

When someone with cancer has nausea and vomiting, it could be the result of one or more causes:

• Certain chemotherapy drugs are the most common causes of nausea and vomiting, especially if given in high doses. When given intravenously, chemotherapy drugs can bring on nausea and vomiting quite quickly. Cancer drugs differ in how much they contribute to nausea and vomiting (called emetogenic potential). Some drugs are more likely to cause these effects than others.

Drugs with a high potential of causing nausea and vomiting*

*Drugs with low or moderate potential to cause nausea or vomiting are not listed here.

• Radiation therapy (radiation-induced), especially radiation therapy to the stomach, abdomen or the brain. The potential to cause nausea and vomiting depends on the amount of and how often radiation therapy is given.
• Anesthesia given for surgery.
• Pain medications, especially opioids.
• The cancer itself, especially cancer affecting the brain, liver or gastrointestinal tract.
• Chemical or electrolyte imbalances in the body, such as high calcium levels (hypercalcemia).
• Constipation or bowel obstruction.

The chances of experiencing nausea and vomiting are increased when cancer treatments are combined, such as chemotherapy given along with radiation therapy.

Symptoms

Nausea

• feeling queasy
• upset stomach
• increased saliva production
• sweating
• dizziness

Vomiting

• the stomach contracts forcefully, which causes stomach contents to be brought up through the mouth

Retching

• gagging or heaving, but nothing is brought up

Management

The most effective way to control nausea and vomiting is to prevent it before it happens. It is also important to treat nausea and vomiting effectively, because it causes a loss of fluids and nutrients from the body (dehydration). This could contribute to fatigue and a loss of appetite and interfere with day-to-day activities.

There are many things one can do to cope with nausea and vomiting:

• Try to eat and drink slowly.
• Relax in an upright position to help ease digestion after eating. Avoid lying down for at least 2 hours after eating.
• Avoid mixing hot and cold foods during the same meal.
• Try meals cold or at room temperature. They have less of an odour that way.
• If possible, avoid being around foods that produce strong smells when they are being prepared.
• Loose clothing may be more comfortable at mealtime. Fresh air can also help.
• Eat small meals often throughout the day.
• Nibble on dry foods, such as crackers, toast, dry cereals or bread sticks, when waking up and every few hours during the day.
• Avoid foods that are overly sweet, greasy, fried or spicy or have strong smells.
• Sip water, juices and other caffeine-free liquids (flat ginger ale, sport drinks) throughout the day. Cool liquids may be easier to drink than very hot or very cold liquids. Try to drink at least 8 to 10 glasses of fluid each day to help prevent dehydration if vomiting.
• Have a light meal or snack before chemotherapy or radiation therapy treatments. Try not eating for 1 to 2 hours before treatment, if nausea usually occurs during treatment. Wait a few hours after treatment before eating again.
• Keep the mouth clean, especially after vomiting.
• Remove dentures or partial dentures on chemotherapy treatment days. Sometimes objects in the mouth can make a person feel like vomiting.
• If nutritional supplements taste too sweet or are too thick, try adding water or milk, drink them over ice or flavour them with fruit.
• Take slow, deep breaths through the mouth if feeling nauseated.
• If vomiting occurs, try sticking to clear liquids (such as broth or juice). Once vomiting settles down, try crackers or plain toast. Then try other liquids such as milk, soups, puddings or milkshakes.

Anticipatory nausea and vomiting

• Lie down in a quiet place for 15 to 30 minutes before treatment begins.
• Place a cool washcloth over the eyes just before receiving chemotherapy.
• Try talking to someone. Chatting can keep your mind busy and will help direct your thoughts away from feeling sick.
• Avoid sounds, sights, and smells that cause nausea and vomiting.

Anti-nausea drugs

The healthcare team can prescribe anti-nausea drugs (anti-emetics) to prevent or reduce nausea and vomiting. People often receive anti-nausea medicines based on the specific chemotherapy drugs they are receiving.

It is important to take anti-nausea drugs as directed at their scheduled times, because it is easier to prevent nausea than treat it once it happens. Anti-nausea drugs work best when they are taken before chemotherapy treatment and for a few days after. Sometimes they can cause side effects, but most people feel that these side effects are worth the benefits. The healthcare team will give instructions about what to do if you vomit within the first hour of taking anti-nausea medication.

Let the doctor know if anti-nausea medications do not seem to be working. Report severe vomiting, vomiting that lasts for more than a day or if nausea prevents you from keeping liquids down.

Other non-drug treatments

Some non-drug methods may help with nausea and vomiting. Some of these are:

• listening to soothing music
• using guided imagery (visualization), for example, imagining yourself in a relaxing or peaceful place
• relaxation exercises
• biofeedback
• meditation or self-hypnosis
• acupressure or acupuncture

These methods may work by affecting a person's perception of their cancer treatment experience or by improving the effectiveness of anti-nausea drugs. They are used more to help treat anticipatory nausea and vomiting. The role of some of these methods, such as acupuncture or acupressure, in controlling nausea and vomiting is being studied in clinical trials.

For more detailed information on specific drugs, go to sources of drug information.