Nausea, Appetite Loss, and Taste Changes During Treatment

Nausea and a shrinking appetite tend to arrive together during cancer treatment. They also feed each other. This page is about those two. Taste and smell changes work differently and have different fixes. We cover them in detail on Food Stopped Tasting Like Food and Managing Food Aversions & Taste Changes After Chemo.

The National Cancer Institute defines nausea as feeling sick to your stomach, as if you have the urge to throw up. Vomiting is the act of throwing up itself. NCI then sorts treatment-related nausea by timing. That matters, because each type is treated differently.

• Acute — occurs within 24 hours after treatment starts.
• Delayed — happens 1 to 7 days after treatment.
• Anticipatory — occurs before treatment begins, triggered by previous experiences.
• Chronic — ongoing after treatment ends.

NCI adds two more types, based on how you respond to medicine. Breakthrough nausea develops within 5 days of starting antinausea treatment. Refractory nausea does not improve with antinausea medications. If either one describes you, say so. Your team can act on that, and it tells them more than saying the pills are not working.

NCI says nausea and vomiting can come from the cancer itself and from treatment. Cancers that commonly cause it include abdominal cancers, brain and central nervous system cancers, advanced cancer, and cancer that has spread to bones.

Nausea from chemotherapy begins minutes to hours after treatment. It usually lasts 24 to 48 hours, and sometimes up to 7 days. Radiation therapy may cause nausea lasting 3 to 4 weeks, especially radiation to the brain, the upper abdomen (belly), or the whole body. Targeted therapy, immunotherapy, and bone marrow or stem cell transplants can cause it too. Nausea after surgery lasts 24 to 48 hours. It comes from the anesthesia and the pain medications. NCI also lists anxiety, pain medications, an empty stomach, and other medical conditions as causes.

Vomiting that is not controlled can lead to dehydration, electrolyte imbalances, and weight loss. That is why it is important to tell your team, rather than putting up with it quietly.

NCI lists several groups of drugs:

• Serotonin blockers, such as ondansetron, granisetron, dolasetron, and palonosetron
• Dopamine blockers, including prochlorperazine, promethazine, and metoclopramide
• NK-1 receptor blockers, such as aprepitant
• Steroids, including dexamethasone
• Benzodiazepines, such as lorazepam
• The antipsychotic olanzapine
• The cannabinoid dronabinol

The range matters. If one drug is not controlling your symptoms, several other kinds are left to try, often in combination. Ask which medicine you have. Ask when to take it. Ask whether you take it on a schedule, or only once nausea has arrived.

For nausea, NCI suggests:

• Stay hydrated. Water, broths, fruit juices, ginger ale, tea, or sports drinks all count.
• Eat cold or bland foods, such as popsicles, pudding, toast, rice, and crackers.
• Try ginger-based foods and drinks.
• Avoid greasy, fried, sweet, or spicy foods.
• Avoid strong food odors, including coffee, fish, onions, and garlic.
• Eat five to six small meals instead of three larger ones.
• Rest upright, or with your head raised, for 30 minutes after meals.
• Keep a symptom log.

NCI also lists complementary approaches (used alongside standard care), including deep breathing, guided imagery, hypnosis, massage, music therapy, meditation, acupuncture from a professional provider, and acupressure using Sea-Band wristbands. Its caution on supplements is firm. Always check with your doctor first, because some supplements may make cancer treatment work less well.

For appetite loss, NCI suggests:

• Eat small meals every 2 to 3 hours, about 5 or 6 meals per day.
• Eat within 1 hour of waking up.
• Eat foods high in protein and calories.
• Eat the high-protein foods first, while your appetite is strongest.
• If solid food does not appeal, drink milkshakes, smoothies, juices, or soups.
• Sip nutrition supplement drinks between meals, such as Ensure and Boost.

NCI says weight loss is more likely with head and neck, lung, pancreatic, or liver cancer. It is also more likely with cancer in the upper digestive system. Treatment side effects can cause eating problems. These include nausea, constipation, mouth sores, dry mouth, painful swallowing, and feeling full quickly. Anxiety, depression, pain and fatigue can play a part too. Tell your team, because some of these can be treated.

• NCI's patient guide is direct: tell your doctor or nurse if you vomit for more than one day, or right after you drink.
• Let your doctor or nurse know if your medicine for nausea is not working.
• Caregivers should watch for dizziness, weakness, or confusion. NCI says these are all signs of dehydration. If you see them, call the care team right away. For emergencies call 911 or go to the ER.
• On weight, NCI says to talk with your doctor or registered dietitian if your appetite drops, and to speak with them right away if you start to lose weight. Ask your own team what amount of loss they want reported and how often to weigh yourself.

Ask your team ahead of time which symptoms are worth a call. Ask how much fluid to drink each day. Ask whether you can see a dietitian.

• National Cancer Institute — Nausea and Vomiting and Cancer: https://www.cancer.gov/about-cancer/treatment/side-effects/nausea
• National Cancer Institute — Appetite Loss and Cancer Treatment: https://www.cancer.gov/about-cancer/treatment/side-effects/appetite-loss
• National Cancer Institute — Chemotherapy and You: Support for People With Cancer: https://www.cancer.gov/publications/patient-education/chemotherapy-and-you.pdf