If you take a sulfonylurea like glipizide or glimepiride and you are too sick to eat normally, sick day guidance generally says to temporarily hold it to avoid low blood sugar, then restart once you are eating again. Confirm with your doctor or pharmacist first.
That short answer covers most cases. But it helps to understand why this pill is different from your other diabetes medicines, and what to watch for while you are unwell. Let's walk through it.
Why this matters
Sulfonylureas are a group of diabetes pills that includes glipizide (Glucotrol), glimepiride (Amaryl), and glyburide (DiaBeta, Glynase). They lower your blood sugar by telling your pancreas to release more insulin.
Here is the catch. According to the FDA prescribing label, all sulfonylurea drugs are capable of producing severe hypoglycemia, which is the medical word for dangerously low blood sugar. The same label notes that low blood sugar is more likely when caloric intake is deficient, in plain words, when you are not eating enough.
That is exactly what a sick day looks like. When you have the flu, a stomach bug, vomiting, or a fever, you often cannot keep food down. So the risk on a sick day is the opposite of what most people expect. The danger is not high blood sugar. It is your sugar falling too low.
How the pill keeps working even when you skip meals
This is the key idea. Sulfonylureas push your body to make insulin whether or not food is coming in.
Normally the timing lines up nicely. The glipizide label explains that the insulinotropic response to a meal occurs within 30 minutes after a dose, so the extra insulin arrives around the same time as your breakfast or dinner. The insulin handles the sugar from your food, and your blood sugar stays in range.
Now take the food away. You take your pill, but you are too nauseated to eat. The insulin still shows up. With no incoming sugar to balance it, that insulin can pull your blood sugar down too far. The CDC lists not eating enough as a cause of low blood sugar for the same reason.
There is a second wrinkle for glimepiride and glyburide. A clinical review of sick day medicines notes that patients should avoid renally excreted sulfonylureas like glibenclamide and glimepiride during vomiting, diarrhea, or fever. When you are dehydrated and your kidneys are working harder, these drugs and their active leftovers can build up and keep lowering your sugar longer than usual.
This is why sick day guidance treats sulfonylureas differently from the rest of your medicine cabinet.
Your sick day plan for sulfonylureas
Use this as a general checklist, not a rule for every person. Your doctor or pharmacist knows your full picture.
- Pause the pill while you cannot eat normally. An international consensus group recommends that sulfonylureas be held when blood glucose is low, which is the situation when you are sick and not eating. This is a short pause, not a permanent stop.
- Watch for low blood sugar signs. The CDC lists shaking, sweating, a fast heartbeat, confusion, dizziness, and hunger as warning signs. If you have a glucose meter, check more often than usual while you are sick.
- Treat a low right away if one happens. Have fast sugar nearby, like juice or glucose tabs, and follow the plan your care team gave you. Even when sick, try to take in some fluid and small bits of carbohydrate if you can.
- Restart when you are eating normally again. Once your appetite is back and meals are staying down, resume your usual schedule unless your doctor told you otherwise. Both the glipizide and glimepiride patient labels remind you to know the symptoms of low and high blood sugar and what to do for each.
- Call your doctor or pharmacist if you are unsure. Reach out if you cannot keep fluids down, your illness lasts more than a day or two, you have repeated lows, or you simply are not sure whether to hold or take your dose.
How sick day rules differ across diabetes and heart medicines
Not every pill follows the same rule on a sick day. This is where people get tripped up. A sulfonylurea is held to prevent low blood sugar, but your other medicines may be held for completely different reasons, and insulin is usually continued. Here is a side by side view.
| Medicine | Sick day move (general guidance) | Main reason |
|---|---|---|
| Sulfonylurea (glipizide, glimepiride, glyburide) | Hold while not eating | Low blood sugar from forced insulin with no food |
| Metformin | Hold | Lactic acidosis risk when dehydrated |
| SGLT2 inhibitor (such as Jardiance) | Hold | Diabetic ketoacidosis, even with normal sugar |
| Insulin | Usually continue, check ketones | Your body still needs background insulin |
| Blood pressure pills (ACE inhibitors, ARBs) | Hold | Kidney strain when dehydrated |
If you want the full reasoning for the others, see our guides on metformin sick day rules, Jardiance sick day rules, blood pressure medicines on sick days, and insulin when you are sick and not eating. If you are also wondering about a skipped dose in general, our guide on a missed dose of diabetes medication can help.
How Pillo helps you pause and restart safely
The tricky part of a sick day is not pausing the pill. It is remembering to start it again once you feel better and your meals are back to normal. People forget, and then they go days without a medicine they actually need.
Pillo is an Android medication reminder app built for exactly this kind of moment.
- Pause a med while you are sick. When your doctor or pharmacist says to hold your sulfonylurea, you can pause that medicine in Pillo so you are not nagged to take a pill you are skipping on purpose.
- Get a restart reminder. Set a reminder to resume once you are eating normally again, so the medicine does not stay paused longer than it should.
- Persistent alarms that do not give up. Pillo's alarm keeps going until you actually confirm the dose, which is helpful when sick day brain fog makes everything easy to forget.
- Manage doses for someone you care for. With dependents management, one person can keep track of medicines for a parent, child, or other dependent inside their own app, so a caregiver can pause and restart on a sick day too.
Pillo does not track your glucose or replace medical advice. It simply helps you take the right medicine at the right time, and not forget to restart after a sick day. You can get Pillo on Google Play.
Frequently asked questions
Should I take glipizide if I am sick and not eating?
General sick day guidance is to hold glipizide while you cannot eat normally, because the pill keeps pushing your body to make insulin even without food, which can cause low blood sugar. The FDA label notes that low blood sugar is more likely when caloric intake is deficient. Restart when you are eating again, and confirm the plan with your doctor or pharmacist.
Is the rule the same for glimepiride and glyburide?
Yes, and there is an extra reason to be careful. A clinical review notes that renally excreted sulfonylureas like glimepiride and glibenclamide should be avoided during vomiting, diarrhea, or fever, because they can build up when you are dehydrated and keep lowering your sugar longer.
What are the warning signs of low blood sugar?
The CDC lists shaking, sweating, a fast heartbeat, nervousness, confusion, dizziness, and hunger. If you feel these and can check your sugar, do so, and treat a low with fast sugar like juice or glucose tabs based on the plan your care team gave you.
When should I restart my sulfonylurea after being sick?
Restart once your appetite returns and meals are staying down, unless your doctor told you otherwise. The patient label reminds you to know the symptoms of low and high blood sugar as you get back to your routine. Setting a reminder helps you avoid leaving the medicine paused too long.
Do other diabetes pills follow the same sick day rule?
No. Metformin is usually held because of a different risk when you are dehydrated, and SGLT2 inhibitors like Jardiance are held for yet another reason. Insulin is usually continued. See our metformin and Jardiance sick day guides for the full picture.
This article is for general education and is not medical advice. Sick day rules vary by person and by health condition. Never start, stop, or change a medicine based on a blog post. Consult your doctor or pharmacist for advice specific to your medications.
