The flu, food poisoning, even a sinus infection can push blood sugar into ranges that range from “annoying” to “dangerous.” A short, written sick-day plan is one of the highest-leverage things you can have ready.
When you’re sick, your body releases stress hormones that drive blood sugar up — sometimes dramatically. At the same time, you may be eating less, dehydrated, vomiting, or unable to keep medications down. The combination is what makes minor illnesses occasionally land patients in the emergency department.
This article walks through the basics of a sick-day plan. Your specific plan should be reviewed with your clinician, since it depends on which medications you take.
The four sick-day basics
- Don’t stop your diabetes medications without checking. The instinct to skip insulin or oral meds when you’re not eating is usually wrong — illness raises blood sugar even without eating
- Check blood sugar more often. Every 2–4 hours is reasonable, more if levels are unstable
- Stay hydrated. Sip clear fluids continuously. Sugar-free if blood sugar is high; with sugar (juice, broth, regular pop) if it’s low
- Watch for ketones. If you have type 1 diabetes — or type 2 on certain medications — and your blood sugar is over 14 mmol/L, check for ketones
What to keep on hand
A small “sick day kit” makes managing illness much easier:
- Glucose tablets or fast-acting sugar (15g packets)
- Test strips and lancets — make sure you have enough
- Ketone strips (urine or blood, depending on your usual method)
- Acetaminophen and ibuprofen (check with your clinician about which is preferred for your kidneys)
- Anti-nausea options you’ve been prescribed
- Sugar-free electrolyte drinks
- A written sick-day plan with phone numbers
Insulin adjustments
If you take insulin, your sick-day plan likely includes some pattern of adjusting doses up or down depending on what your readings show. Don’t try to invent these adjustments mid-illness — get them written down at a routine appointment when you’re feeling well, and keep the plan somewhere accessible.
A common pattern for type 1 patients includes: continue your basal insulin even if you’re not eating, add small correction doses for high readings every 3–4 hours, and call if readings stay over 14 despite corrections.
Medications that need extra attention
Some diabetes and blood pressure medications have special sick-day considerations:
- SGLT2 inhibitors (empagliflozin, dapagliflozin, canagliflozin) — generally held during significant illness, especially with vomiting or dehydration, due to risk of euglycemic ketoacidosis
- Metformin — held if you’re significantly dehydrated
- ACE inhibitors and ARBs — sometimes held during severe vomiting or diarrhea to protect kidney function
If your medication list includes any of these, it’s worth asking your clinician what they want you to do during illness — the answer is straightforward but important.
The plan beats the panic
Most diabetes-related ED visits during illness are preventable. Patients who do well during sick days tend to share three things: they have a written plan, they call early rather than late, and they’ve practiced the plan once or twice when they had a minor cold so it didn’t feel new during the flu.
If you don’t have a sick-day plan, ask for one at your next visit. It’s a 10-minute conversation that can prevent a much longer one in the ER.
