Cancer: Facts About Nausea and Vomiting - Network Health

Cancer: Facts About Nausea and Vomiting
Treatments for cancer, and sometimes the cancer
itself, may cause you to feel sick to your
stomach. You may feel nauseated or vomit. You
may worry about these side effects before you
start treatment. Or you may have very little
nausea or vomiting, or none at all. If you do feel
sick, medicines and home treatments can help.
Causes of nausea and vomiting
Nausea and vomiting can be caused by:
• Chemotherapy.
• Radiation therapy.
• Your cancer itself.
• Another illness.
• Medicines you might be taking.
Nausea or vomiting caused by
chemotherapy
Chemotherapy can cause several types of nausea
and vomiting:
• Acute nausea or vomiting, which happens
when you start chemotherapy. It may start
right after treatment. It is often at its worst
within 5 to 6 hours after your treatment.
• Delayed nausea or vomiting, which usually
starts more than a day after your
chemotherapy. It can last for 6 to 7 days. It
is usually at its worst 2 to 3 days after your
treatment.
• Anticipatory nausea or vomiting, which is
triggered by your memory of a bad
experience. You may have this type of nausea
or vomiting before or during chemotherapy.
Sometimes you may vomit even though you are
taking medicines that help keep you from feeling
sick.
• You may have breakthrough vomiting if
you are not taking a high enough dose of
nausea and vomiting medicine.
• You may have refractory vomiting if your
nausea and vomiting medicine stops working
altogether.
Radiation-induced nausea and
vomiting
Radiation therapy can cause nausea and
vomiting. The symptoms may start half an hour
after treatment, and last several hours. How sick
you feel depends on:
• What part of your body is being treated.
You are most likely to feel sick if you are
having radiation therapy in the area of your
digestive system (for example, your stomach
or small intestine) or your brain.
• How much of your body is being treated.
The larger the area, the more likely you will
feel sick.
• How much radiation is used. The higher
the dose of radiation, the more likely you
will feel sick.
• If you are also being treated with
chemotherapy. If you have both radiation
therapy and chemotherapy, you are more
likely to feel sick to your stomach.

• Your radiation treatment schedule. If your
treatments are close together—every day, for
instance—your body does not have as much
time to recover.
What happens if nausea and
vomiting are not controlled?
Vomiting too much can cause you to get
dehydrated. Dehydration causes problems with
electrolytes, which are minerals found naturally
in the body. These minerals keep the body's
balance of fluids at the right level. Problems
with your electrolyte balance can affect the way
your body functions. Dehydration can be mild
or severe and can cause:
• Increased thirst and a dry mouth.
• Weakness.
• Dizziness.
• Palpitations (the uncomfortable feeling that
your heart is beating fast or irregularly).
• Confusion.
• Feeling slow or sluggish.
• Fainting.
• Not sweating even though you may be warm.
• Urinating very little or not at all.
When are nausea and vomiting an
emergency?
Call 911 anytime you think you may need
emergency care. For example, call if:
• You passed out (lost consciousness).
• You vomit blood or what looks like coffee
grounds.
Call your doctor now or seek immediate
medical care if:
• You cannot stop vomiting.
• You get dizzy or weak.
• You have signs that you need more fluids.
You have sunken eyes and a dry mouth, and
you pass only a little dark urine.
• You have a lot of pain and cramps.
• Your belly swells.
• You are vomiting so much that you cannot
keep your medicine down.
• You have any problems with your medicine.
Communicating with your doctor
Before you start treatment, talk to your doctor
about nausea and vomiting. Ask the following
questions:
• Will my cancer treatment cause nausea and
vomiting?
• Are there ways to control my nausea and
vomiting?
• How will you decide how to treat my nausea
and vomiting?
• Do these treatments have any side effects?
• What can be done if the treatments don't
work?
• Can I do anything to help myself?
Keep track of when you have
symptoms and what you do to help
relieve them. Refer to the record when
you talk with your doctor.
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of this information, which does not replace medical advice. 2011-09-zu1401