Diabetes Forecast

Sick-Day Rules for Managing Diabetes

By Erika Gebel Berg, PhD , ,


In response to illness, the body boosts levels of stress hormones to help fight infection, but these hormones can drive up blood glucose levels. Vomiting and diarrhea disrupt normal digestion, which can slow the absorption of foods and drive down blood glucose levels, sometimes too low if you're using certain medications. To handle these diabetes control challenges, experts recommend following "sick-day rules" to ensure blood glucose levels stay safe and put you on the road to recovery.

Check, Check, Check

Each person is different, especially when it comes to how the body responds to illness. Some patients are completely unaffected by sickness, while others are sensitive to a wide variety of illnesses, says Rachelle Gandica, MD, a pediatric endocrinologist at the Columbia University Medical Center. Plus, each type of illness can affect a person's blood glucose differently. It's important for insulin users to check blood glucose every two to three hours when sick. Even non-insulin users should check more often than usual, says Gandica.


Keep taking your medications while sick, though perhaps with some dose adjustments to compensate for high blood glucose levels or to avoid low blood glucose if you can't eat. Ask your health care provider how to adjust your particular medication regimen.

For insulin users, the "rule of thumb is to continue taking basal and bolus insulin," says David Dugdale, MD, FACP, professor of medicine at the University of Washington. But recognize that if you don't eat, you wouldn't take a bolus. Basal or long-acting insulin is needed throughout illness, and you may need more than usual.

For ill people with type 2 diabetes, the insulin recommendations are the same as for type 1, but figuring out what to do about oral medications may actually be harder, says Dugdale. "They may take pills that are designed to offset what they eat. There is no formula for that," he says. "Some of the pills should be adjusted if [people] are sick enough that they can't eat." For example, sulfonylurea use may need to be reduced because the medication can increase the risk of hypoglycemia. People with type 2 diabetes using metformin may need to switch to insulin during a serious illness, such as gastrointestinal flu, because dehydration and the decreased kidney function that may result increase the risk for a rare complication, lactic acidosis, associated with metformin use. Dugdale suggests asking your doctor if you should take a break from amylin (Symlin) while ill. "It just adds another set of variables that might make it harder to do the right thing," he says.

Mind the Ketones

One of the most serious risks of sickness in people with diabetes is diabetic ketoacidosis (DKA), a life-threatening condition caused by too little insulin in the body in combination with the stress hormones associated with illness.

Check urine ketones frequently while sick. Urine ketones are indicated on a test strip as trace, low, moderate, high, and very high. "Any amount should be noted and reported to the doctor," says Dugdale. "If it is more than 'low,' the patient should get specific instructions on how to turn things around and may need to get intravenous medication." Check with your own provider for how to deal with high ketones, and make a plan for when levels don't come down. For parents of infants, Gandica offers this tip: "Put some cotton balls in the diaper, and then when the child voids, you can squeeze the cotton balls out onto a urine ketone strip."


Dehydration is a risk factor for DKA, so it's critical to stay well hydrated while ill. A cup of fluid every hour should be enough, but keep in mind that vomiting and diarrhea increase the risk for dehydration. Dugdale recommends carbohydrate-free fluids, such as water, to help keep blood glucose levels from rising too high. "I've seen people with DKA who kept drinking sugary fluids without recognizing how much sugar they were taking, which just aggravated their blood sugar," he says. "If they take fluids with sugar, they need to account for that some way." For people who are sick to their stomach and not eating, Dugdale says this rule can be bent in order to take in some nourishment. In that situation, Gandica recommends alternating between sugar-free and sugary fluids or, if drinking is making you nauseous, between sugar-free and sugary Popsicles.

Check OTC Med Label

Most over-the-counter (OTC) cold and flu medications are generally safe for people with diabetes, says Gandica. People with kidney problems may have certain restrictions, though. Always check with a doctor to make sure OTC medications are safe and don't react with any of your prescription medications, for diabetes or other conditions.

Know When to Get Help

If you have ketones, high blood glucose, or both, and you can't get them to come down (especially if you're using insulin), "that merits a call to the doctor's office," says Dugdale. If you or your child has signs or symptoms of diabetic ketoacidosis (see below), it's time for a visit to the emergency room. Being sick increases your risk for developing diabetic ketoacidosis (DKA). Keep an eye out for these symptoms when sick and go to the emergency room if you suspect DKA.

Early symptoms of diabetes ketoacidosis:

  • Thirst or a very dry mouth
  • Frequent urination
  • High blood glucose levels (typically over 250 mg/dl, although ketones can occur at lower levels)
  • High levels of ketones in the urine or blood

Later symptoms of diabetes ketoacidosis:

  • Constantly feeling tired
  • Dry or flushed skin
  • Nausea, vomiting, or abdominal pain
  • Difficulty breathing
  • Fruity odor on the breath
  • A hard time paying attention, or confusion

Source: American Diabetes Association

Diabetic ketoacidosis is a serious and immediate health concern. Have a strategy in place to prevent DKA.

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