The side effects of chemotherapy (chemo) depend on the type of chemo and the amount given. Nausea with or without vomiting is common. Anticipating and managing side effects can help to reduce them and even prevent them.
What are the types of nausea and vomiting linked to chemo?
Just as each person is different, so is their reaction to treatment. You may have severe, mild, or no side effects. Talk with your cancer care team about possible side effects and what can be done about them before treatment begins.
Nausea is when you feel sick, like you might throw up. Vomiting is when you throw up. The medicines used to control and prevent these common side effects are called antiemetics, or antinausea medicines.
The National Cancer Institute says that, based on the time when nausea and vomiting happen, these are the types of nausea and vomiting linked to chemo:
Anticipatory nausea and vomiting
After getting a few treatments, some people feel nauseous and begin vomiting in anticipation of the next treatment, or before they even start it. This reaction is often caused by something related to the treatment, like the smell of an alcohol swab or the sight of a medical uniform.
Antinausea medicines don't always prevent anticipatory nausea and vomiting. But they may help. Actions that calm or distract the person tend to work more often. These may include guided imagery, hypnosis, relaxation, behavioral modification, or activities like music or video games. Anticipatory nausea is often a learned response. The best way to keep it from happening is to prevent or treat acute and delayed nausea.
Acute nausea and vomiting
This physical reaction happens within 24 hours of getting chemo. It can be mild, moderate, or severe. Your healthcare provider can give you medicines to help control acute nausea and vomiting.
Delayed nausea and vomiting
For some people, nausea and vomiting may happen more than 24 hours after getting chemo. This is more common in people getting high doses of chemo, those who have acute nausea and vomiting, women, people who drink little or no alcohol, and young people. Medicines that are used for acute nausea and vomiting can also be used in delayed nausea and vomiting.
Nausea and vomiting in advanced cancer and chronic nausea and vomiting
In people with advanced cancer, nausea and vomiting may become chronic (long-term) and not linked to chemo. The nausea may be related to other medicines used for pain or depression. Or it may be the direct result of a brain or abdominal tumor.
People with advanced cancer may also have constipation, abnormal levels of certain substances in the blood, dehydration, and stomach ulcers. All of these can lead to nausea and vomiting.
What causes nausea and vomiting?
The brain controls nausea and vomiting. Nausea is controlled by autonomic nerves. These nerves control involuntary body functions, such as heartbeat and breathing. Many irritants, such as smells, taste, anxiety, pain, motion, or digestive chemicals can trigger a vomiting center, which starts the vomiting as a reflex.
There are many factors linked to whether a person will have nausea and vomiting. Some chemo medicines are more likely to cause it. Women and people younger than age 50 are more likely to have nausea and vomiting. People who are prone to motion sickness or anxiety are also more likely to react to chemo with nausea and vomiting.
Managing nausea and vomiting
In most cases, antinausea medicines, sometimes along with alternative therapies, can help to reduce nausea and vomiting. It's very important to maintain the body's electrolyte balance and to make sure that vomiting doesn't lead to the loss of vital nutrients. Uncontrolled nausea and vomiting are serious problems. They must be managed to prevent malnutrition, dehydration, and mental changes.
The American Cancer Society provides these tips for dealing with nausea and vomiting:
Eating and drinking
Eat foods that sound good to you.
Eat and drink slowly.
Eat many small meals throughout the day instead of 3 full meals. Have a snack at bedtime.
Don't skip meals or snacks. You may feel more nauseated when your stomach is empty.
Stay away from strong smells by eating food that is cold or at room temperature.
Drink clear liquids served cold. Sip them slowly and often throughout the day to prevent dehydration.
If you are nauseated in the morning, keep dry foods, such as cereal or crackers, at your bedside. Eat them before you get up. But don't do so if you have throat or mouth sores or a lack of saliva.
Don't eat sweet, fatty, spicy, or fried foods.
Chew food well to help with digestion.
Drink an hour before or after, instead of with, each meal.
Rest but don't lie down for at least an hour after eating.
Eating before treatment
A light meal before treatment is helpful unless you become nauseated during chemo. If nausea is a problem, don't eat for at least several hours before treatment.
Your healthcare provider will likely prescribe antinausea medicines. Be sure you know how they work and how to take them.
Take your "as needed" antinausea medicine as soon as you feel nausea. Don't wait until you're throwing up.
Stay away from strong smells that may be unpleasant for you, such as cooking smells, perfume, and smoke.
If you are feeling nauseated, distract yourself.
Breathe deeply and slowly when you are feeling nauseated.
Wear loose-fitting clothes.
Tell your healthcare providers about any nausea or vomiting you have. Be sure to report vomiting that lasts more than a day. Also contact your healthcare team if you can't keep liquids or medicines down. There are a lot of different antinausea drugs that can be used to control these side effects. Let your provider know if the medicine you're using doesn't work. These medicines work in different ways. So you may need more than 1. Or you may need to try a few to find 1 that works best for you.