PDQ® Supportive Care Patients
This patient summary on nausea and vomiting is adapted from the summary written for health professionals by cancer experts. This and other accurate, credible information about cancer treatment, screening, prevention, supportive care, and ongoing clinical trials, is available from the National Cancer Institute. Nausea and vomiting are two of the most upsetting side effects for cancer patients. This brief summary describes nausea and vomiting, their causes, and treatment.
Prevention and control of nausea and vomiting are very important in the treatment of cancer patients. Uncontrolled nausea and vomiting can lead to chemical changes in the body, loss of appetite, physical and mental problems, a torn esophagus, broken bones, and the reopening of surgical wounds. Uncontrolled nausea and vomiting may interfere with the patient's ability to receive cancer treatment and care for himself or herself.
Nausea is an unpleasant wavelike feeling in the back of the throat and/or stomach that may or may not result in vomiting. Vomiting is the forceful elimination of the contents of the stomach through the mouth. Retching is the movement of the stomach and esophagus without vomiting and is also called "dry heaves." Even though treatments have improved, nausea and vomiting continue to be worrisome side effects. Nausea may be far more distressing for patients than vomiting.
Nausea and vomiting caused by chemotherapy are classified as anticipatory, acute, or delayed. Anticipatory nausea and vomiting may occur before or during chemotherapy, and appear earlier than these symptoms would be expected. Anticipatory symptoms may also appear in patients who are receiving radiation therapy. Acute nausea and vomiting usually occur within 24 hours after chemotherapy has begun. Delayed, or late, nausea and vomiting occur more than 24 hours after chemotherapy and can last several days. Delayed nausea and vomiting can cause serious illness (such as dehydration) that require patients to be hospitalized.
Nausea and vomiting are controlled by the central nervous system. Nausea is controlled by a part of the nervous system that controls involuntary bodily functions. Vomiting is a reflex controlled by a vomiting center in the brain. Vomiting can be stimulated by various triggers, such as smell, taste, mental upset, pain, motion, changes in the body caused by inflammation, poor blood flow, or irritation.
Not all cancer patients will experience nausea and/or vomiting. The most common causes are certain chemotherapy drugs and radiation therapy to the gastrointestinal (GI) tract, liver, or brain. Other possible causes of nausea and vomiting include fluid and electrolyte imbalances such as hypercalcemia, dehydration, or too much water in the body's tissues; tumor growth in the GI tract, liver, or brain; constipation; certain drugs; infection or blood poisoning; kidney problems; and mental factors.
Anticipatory nausea and vomiting occur before treatment as a response to other triggers in the environment (such as, certain objects, odors, or tastes). For example, a person who begins chemotherapy and smells an alcohol swab at the same time, may later experience nausea and vomiting at the smell of alcohol alone. Smells are more likely to trigger nausea, while thoughts of the treatment will trigger vomiting. Not all patients receiving chemotherapy experience nausea and/or vomiting before or during chemotherapy. Usually, the pattern of anticipatory nausea and vomiting is set by the fourth or fifth course of treatment. Certain factors may help predict which patients are more likely to experience anticipatory nausea and vomiting. These factors include certain chemotherapy treatments, symptom and mental distress, mood disorders, and limited ability to cope with the stress of treatment.
Chemotherapy and mental factors may contribute to the development of anticipatory nausea and vomiting as listed below:
Age may be a factor in nausea and vomiting. Younger patients tend to receive more aggressive chemotherapy regimens and therefore experience more nausea and vomiting.
Hypnosis, relaxation, and behavioral modification techniques may reduce anticipatory nausea and vomiting. Some antianxiety drugs may also be helpful.
Chemotherapy is the most common treatment-related cause of nausea and vomiting. The drug, dose, schedule of administration, route, and factors that are unique to the patient all determine how often nausea occurs and how severe it will be. Usually, these symptoms can be prevented or controlled.
Radiation therapy to certain parts of the body can also cause nausea and vomiting. Patients who are receiving radiation to the GI tract or brain are more likely to experience nausea and vomiting than are patients who are receiving radiation therapy for cancer in other sites. When a large area of the GI tract, especially the small intestine and stomach, receives radiation therapy, the patient is likely to experience nausea and vomiting. Because cells of the GI tract are dividing quickly, they are very sensitive to radiation therapy. Radiation to the brain is thought to stimulate the brain's vomiting center. In general, the higher the daily dose of radiation and the greater the amount of tissue that is exposed, the more nausea and vomiting are likely to occur. Total-body irradiation before bone marrow transplantation frequently causes nausea and vomiting.
Nausea and vomiting caused by radiation therapy may be acute and temporary, usually occurring one half to several hours after treatment. Usually, symptoms improve on days when no treatment is given. Nausea and vomiting may gradually worsen over the course of treatment in patients receiving radiation therapy to the GI tract.
Antinausea drugs are the most common treatment for nausea and vomiting caused by cancer therapy. These drugs may be used alone or in combinations. Some drugs last only a short time in the body, and need to be given more often, while others last a long time and do not need to be given as often. Blood levels of the drug(s) must be kept constant in order for nausea and vomiting to be controlled effectively.
Some drugs that are commonly used to treat nausea and vomiting are listed below:
Anticipatory nausea and vomiting often do not respond to standard antinausea therapy. Since the vomiting center in the brain is not directly triggered in anticipatory nausea and vomiting, antinausea drugs, which affect this center, do not work well. Antianxiety drugs work better at controlling anticipatory nausea and vomiting. Some drugs may block the memory of nausea and vomiting after treatment.
Other methods to control anticipatory nausea and vomiting include changing the patient's thinking and behavior, distracting the patient, changing the place and people who give the chemotherapy, using biofeedback, and blocking taste sensation with another strong taste (such as, lemon).
Hypnosis, relaxation, imagery, and desensitization may be used to help the patient identify the trigger that causes nausea and vomiting and create a new response to the trigger. Guided imagery or relaxation is used to distract the attention of the patient away from the trigger that causes nausea and vomiting. This distracts the vomiting center in the brain. Relaxation training, progressive muscle relaxation, and guided imagery may slowly lessen anxiety associated with chemotherapy. Relaxation techniques help relax the gastrointestinal and stomach muscles and block the chain of events that lead to nausea and vomiting. These techniques are very helpful in relieving nausea and giving the patient a sense of control.
An orientation program to educate patients about chemotherapy procedures and the medical surroundings can lessen stresses related to chemotherapy, and may help the patient cope.
Children with cancer may experience anticipatory nausea and vomiting. Hypnosis, relaxation, and distraction (such as playing video games) work well in lessening chemotherapy-related nausea and vomiting in children and youth.
For more information, call the National Cancer Institute's Cancer Information Service at 1-800-4-CANCER (1-800-422-6237); TTY at 1-800-332-8615. The call is free and a trained information specialist is available to answer your questions.
There are many other places to get information about cancer treatment and services. Check the social service office at your hospital for local and national agencies that can help with finances, getting to and from treatment, care at home, and dealing with other problems.
Write to the National Cancer Institute at this address:
PDQ is a computer system that gives up-to-date information on cancer and its prevention, detection, treatment, and supportive care. PDQ is a service of the National Cancer Institute (NCI) for people with cancer and their families and for doctors, nurses, and other health care professionals.
To ensure that it remains current, the information in PDQ is reviewed and updated each month by experts in the field of cancer treatment, prevention, screening, and supportive care. PDQ also provides information about research on new treatments (clinical trials), doctors who treat cancer, and hospitals with cancer programs. The information in this summary is based on the summary for health professionals on this topic and addresses the special needs of patients with cancer and their families during cancer treatment.
PDQ can be used to learn more about current care for patients with cancer. You may find it helpful to discuss this information with your doctor, who knows you and the facts of your disease and can help answer questions and ease concerns. PDQ can also provide the names of additional health care professionals who can help you and your family during the treatment of your disease.
Date Last Modified: 11/1998