Hydration Plan During Cancer Treatment

Fluid is not a background detail during cancer treatment. It often decides whether a rough week ends at home or in the infusion unit hooked up to a bag of saline. Vomiting, diarrhea, fever, and a sore mouth drain fluid faster than thirst can warn you.

Thirst is an unreliable alarm here anyway. Nausea flattens it. Mouth sores make drinking hurt, so you avoid it. A dry mouth can leave you thirsty even when you have been drinking steadily. A plan you follow by the clock works better than one you follow by feel.

Almost anything liquid counts toward your total. The NCI booklet Eating Hints lists water, weak caffeine-free tea, clear apple juice, carbonated drinks, fruit-flavored drinks, sports drinks, bouillon, gelatin, popsicles, and fruit ices among clear liquids. Its full-liquid list adds broth, milkshakes, smoothies, yogurt, ice cream, custard, pudding, and supplement drinks such as Ensure and Boost.

For a baseline, Eating Hints says most adults should drink 8 to 12 cups of liquid a day. The American Cancer Society suggests 9 to 13 cups a day when mouth sores are part of the picture. Treat both as starting points. Heart failure, kidney disease, and some medicines change the number in either direction, so get your own figure from the team.

Diarrhea and vomiting do not only take water. They take sodium and potassium with it. Replacing the water alone leaves you with less salt in the tank than you started with.

NCI advises clear liquids such as water or broth to replace fluids and electrolytes, and notes that room temperature liquids are easiest on the stomach. Eating Hints is more specific: reach for drinks with sodium and potassium, such as bouillon, fat-free broth, or sports drinks like Gatorade or Propel. Foods help too. NCI names peeled and boiled potatoes, soup, bananas, applesauce, and crackers.

Oral rehydration solution is the strongest option. The National Institute of Diabetes and Digestive and Kidney Diseases explains that these solutions contain both glucose and electrolytes, and that you can buy them ready-made or mix them at home.

There is a real caveat, and it applies to most readers of this page. NIDDK says that older adults, people with a weakened immune system, and people with diabetes or kidney disease should talk with a doctor before drinking oral rehydration solutions. Cancer treatment puts many people in at least one of those groups. Ask once, in advance, then keep the packets in the cupboard so the answer is ready when you need it.

One thing to skip entirely: MedlinePlus warns not to take salt tablets, because they can cause serious complications.

Daily totals are hard to hit and easy to lose track of. Hourly targets are not.

• Spread it through the day. Keep a water bottle nearby, as Eating Hints suggests.
• Sip rather than gulp. NCI suggests sipping only small amounts of liquid during meals, so fluid does not crowd out food.
• Get the temperature right for the symptom. Room temperature sits easiest when your gut is unsettled. For nausea, NCI suggests cold things such as popsicles, pudding, yogurt, and gelatin.
• Use a straw when your mouth is sore, so liquid bypasses the worst spots.
• Freeze it. Ice chips and popsicles get fluid in when a full cup feels impossible.
• Replace losses as they happen. ACS suggests drinking at least 1 cup of liquid after each loose bowel movement.
• Drink calories if eating is hard. Eating Hints suggests a protein shake, smoothie, or milkshake when it is hard to eat.
• Measure it. Use one marked bottle and refill it. Guessing at "about two liters" is how people end up short.

Dehydration announces itself before it becomes dangerous, if you know what to watch. MedlinePlus lists these as mild to moderate signs: thirst, a dry or sticky mouth, not urinating much, darker yellow urine, dry and cool skin, headache, and muscle cramps.

Urine is an easy daily check. MedlinePlus lists darker yellow urine as a sign of mild to moderate dehydration. Passing no urine is a sign of severe dehydration.

Eating Hints suggests drinking only clear liquids for 12 to 14 hours after an episode of diarrhea, then adding food back gradually. It says to contact your doctor if diarrhea continues past 24 hours.

NIDDK adds two rules about over-the-counter antidiarrheal medicine. See a doctor if the diarrhea gets worse or lasts more than 2 days while you are taking one. And do not take them at all if you have bloody stools or a fever, which can signal an infection that needs treating rather than slowing down.

Call your oncology team straight away if your temperature reaches 100.4°F (38°C) or higher during treatment. CDC says a fever during chemotherapy is a medical emergency and to call your doctor right away. Know which number to call when the office is open and when it is closed. If you cannot reach anyone, go to an emergency department and tell them you are having cancer treatment. CDC says an infection during chemotherapy can be life-threatening, so do not wait until the office opens.

Contact your oncology team the same day if:

• You cannot keep fluids down.
• You have seven or more bowel movements a day above your usual number. NCI grades this as severe and says it can be life-threatening.
• You are passing much less urine than usual, or none at all.
• You feel dizzy or lightheaded when you stand up.

MedlinePlus lists these as signs of severe dehydration: not urinating, dry shriveled skin, irritability or confusion, dizziness, rapid heartbeat, rapid breathing, sunken eyes, and listlessness. Call 911 if someone loses consciousness, becomes confused or has a seizure, has a fever over 102°F (38.8°C), or is not improving despite treatment.

• How many cups a day should I aim for, given my kidneys and my heart?
• Is an oral rehydration solution safe for me, and which product should I buy?
• Should I keep antidiarrheal or anti-nausea medicine at home, and when exactly do I take it?
• Does anything in my treatment need extra fluid before or after infusion day?
• At what point would you bring me in for intravenous fluids rather than waiting?
• Which symptom means the emergency room rather than a phone call?

Read next: Staying Hydrated During Cancer Treatment, Eating When You Have Nausea, Managing Diarrhea During Cancer Treatment, Food and Fluid Plan for Chemo Day, and What to Eat After Diarrhea During Treatment.

• https://www.cancer.gov/publications/patient-education/eatinghints.pdf
• https://www.cancer.gov/about-cancer/treatment/side-effects/diarrhea
• https://www.cancer.gov/about-cancer/treatment/side-effects/nausea
• https://www.niddk.nih.gov/health-information/digestive-diseases/diarrhea/treatment
• https://medlineplus.gov/ency/article/000982.htm
• https://www.cancer.org/content/dam/cancer-org/cancer-control/en/booklets-flyers/nutrition-for-the-patient-with-cancer-during-treatment.pdf
• https://www.cancer.gov/about-cancer/treatment/side-effects/infection