Diabetes Forecast

Sick Day Rules

How to manage diabetes with the flu

By Allison Tsai , , ,


It may start as a tickle in your throat or intense fatigue, but before you know it, you have the full-blown flu. While a common cold will develop slowly, the flu will come on suddenly and knock you out with aching muscles, high fever, and chills for a few days. The flu puts added stress on your body—and diabetes management. Establish a plan of action with your doctor before experiencing those telltale signs, says David Baidal, MD, assistant professor of medicine in the Division of Endocrinology, Diabetes, and Metabolism at the University of Miami Diabetes Research Institute.

Every illness is different, so check with your doctor for your specific sick-day needs. Read on forsome guidelines to keep in mind.

Check Yourself

When you’re feeling under the weather, it’s important to check your blood glucose and to monitor for ketones, if you’ve been directed to do so.

Blood Glucose: Frequent blood glucose monitoring is essential on sick days. “It may need to be done as frequently as every two to four hours to ensure that [glucose] is staying within a very good range,” says Baidal. You and your doctor should determine what blood glucose range is best for you. If you don’t know your target range, ask about it at your next appointment.

Ketones: When you don’t have enough insulin in your bloodstream to ferry glucose into the cells for energy, the body burns fat instead, which produces ketones. The stress hormones released during illness accelerate this process. Too many ketones can increase the acidity in the blood and lead to diabetic ketoacidosis (DKA), a serious medical issue. Checking for ketones is important for those with type 1 diabetes and people with type 2 who are on basal-bolus insulin therapy, says Marie McDonnell, MD, director of the Brigham Diabetes Program at Brigham and Women’s Hospital in Boston. If your blood glucose is 250 mg/dl or higher and it’s not coming down with insulin, then do a ketone blood or urine check. If you do detect ketones, call your doctor to discuss next steps. Know when to seek emergency services (“Emergency Signs,” below).

Stay the Course

It’s tempting to stop taking your medications when you don’t feel well, but it’s better to continue taking most prescription meds even when you’re ill, says McDonnell. When in doubt, call your doctor for guidance. You may need to alter your dose of select diabetes drugs—particularly insulin and sulfonylurea pills.

Insulin: During the flu and other sudden illnesses, your body releases stress hormones, which raise blood glucose. And illness often causes dehydration, another cause of high blood glucose. “Typically patients require more insulin during that period of time,” Baidal says.

Basal: Always take your long-acting basal insulin, even if you’re not eating, says Clare Lee, MD, assistant professor of medicine in the Division of Endocrinology, Diabetes, and Metabolism at Johns Hopkins University School of Medicine. Illness raises your blood glucose, and your body needs this circulating “background” insulin. Talk to your doctor about if and how to adjust your basal insulin. Insulin pump users, for example, can set a temporary basal rate for a select number of hours to automatically increase (or decrease) the amount of background insulin they’re receiving.

Bolus: You will likely still need to take fast-acting mealtime insulin while sick. Use it as directed to cover any food you eat, “and to correct blood glucose if it’s high during illness,” says McDonnell. Talk with your doctor about how to adjust your bolus doses for sick days.

Sulfonylureas: These drugs signal your pancreas to secrete insulin. If you’re not taking in enough food—and especially if you’re also vomiting—you could end up with low blood glucose (hypoglycemia), Lee says. Your doctor may suggest you reduce the dose, or possibly skip the med until you’re eating again.\

Be OTC Aware

Before self-medicating, get smart about two types of over-the-counter cold and flu medications, says McDonnell. While cough syrup and decongestants are safe when used as directed, it’s good to understand how they can affect you.

Cough Syrup: Opt for sugar-free varieties of liquid cold and cough medicines. The regular versions have sugar, and while it won’t have a huge impact on your blood glucose, you should always put your diabetes management first, McDonnell says.

Nasal Decongestants: Be aware that medications with pseudoephedrine can increase blood pressure and may increase blood glucose, too. “It acts a little bit like a stress hormone,” McDonnell says.

Drink Up

If your blood glucose is on the low side and you’re not eating much, drink sugar-containing beverages, such as a sports drink, to prevent hypoglycemia, Baidal says. But if your blood glucose is high or if you are able to eat, stick with water to drink (or opt for sugar-free drinks).

Eat Regularly

Try to eat your typical meals, even when you don’t feel well, as your body needs more fuel when you’re sick, says Baidal. Try soft, bland foods, or stick with a sports drink until you can eat.

Go Back to Basics

Once your illness resolves, remember to return to your normal medication and insulin doses if you had scaled up or down while sick, says McDonnell. This will help you avoid high or low blood glucose as you transition from your bed back to regular life.

Emergency Signs

The flu rarely involves a trip to the hospital, says David Baidal, MD, assistant professor of medicine in the Division of Endocrinology, Diabetes, and Metabolism at the University of Miami Diabetes Research Institute. But it can happen. Here are some clues that it’s time to head to the emergency room.

  • You’ve been vomiting or have had diarrhea for several hours, and you’re unable to keep food or drink down.
  • Your blood glucose is persistently above 250 mg/dl despite insulin correction doses, and you have large amounts of ketones.
  • You’re having difficulty breathing, extreme dizziness, fatigue, or a change in mental status.
  • You’ve lost more than 5 pounds during the illness.
  • You’ve had a fever of more than 101 degrees for more than 24 hours.

More information on how to monitor for ketones.

Be Prepared

People with diabetes have a greater risk for severe complications from the flu, such as bronchitis and pneumonia. That’s why prevention is so important: Get your flu vaccine every year, and make sure you’ve had your pneumococcal vaccine to prevent pneumonia. More about important vaccinations.



Take the Type 2
Diabetes Risk Test