Sick Day Rules for Diabetes Medications: How to Prevent DKA and AKI During Illness
Sick Day Medication Guide Calculator
Your Situation
Personalized Recommendations
Medication Guidance
Monitoring Plan
Check blood sugar every 2-4 hours (at least 6 times daily).
Test for ketones if blood sugar exceeds 240 mg/dL (13.3 mmol/L).
Hydration Requirements
Aim for at least 1,500 mL (6 cups) of fluid per day.
Choose water, sugar-free electrolyte drinks, or broth.
Emergency Signs (Call 911 if you experience these)
- Vomiting for more than 4 hours
- Diarrhea for more than 6 hours
- Ketones above 0.6 mmol/L (blood) or 1.5 mmol/L (urine)
- Low blood sugar below 70 mg/dL that doesn't improve after 15g carbs
- Confusion, difficulty breathing, or severe abdominal pain
When you’re sick with a cold, flu, or stomach bug, your body is under stress. For people with diabetes, that stress can turn a minor illness into a medical emergency. Diabetic ketoacidosis (DKA) and acute kidney injury (AKI) don’t wait for you to feel better-they can strike fast, especially if you’re taking the wrong medications or skipping key checks. The good news? You can prevent most of these emergencies with simple, clear rules. The bad news? Many people don’t know them-or they’ve heard conflicting advice from different doctors.
Why Illness Is Dangerous for People with Diabetes
When you’re sick, your body releases stress hormones like cortisol and adrenaline. These hormones push your liver to dump more glucose into your bloodstream. At the same time, your body may not use insulin properly. For people with type 1 diabetes, this can trigger DKA-your body starts burning fat for energy because it lacks insulin, producing toxic ketones. For people with type 2, especially those on certain medications, dehydration from vomiting or fever can cause your kidneys to shut down, leading to AKI.A 2022 study in JAMA Internal Medicine looked at nearly 48,000 hospital admissions and found that people with diabetes are 300% more likely to develop DKA and 200% more likely to suffer AKI when they’re sick. The biggest culprits? Not blood sugar levels alone-but what you’re taking to manage them.
Which Diabetes Medications to Stop (and When)
Not all diabetes meds are safe during illness. Some become dangerous when you’re dehydrated or not eating. Here’s what you need to know:- Metformin: Stop immediately if you’re vomiting, have diarrhea, or have a fever. Metformin builds up in your blood when your kidneys aren’t working well, and that can cause lactic acidosis-a rare but deadly condition. A 2019 study in the New England Journal of Medicine showed the risk jumps 8.3 times when creatinine levels rise above 1.5 mg/dL. Even if you feel fine, if you’re not keeping fluids down, stop it.
- SGLT2 inhibitors (like empagliflozin, dapagliflozin, canagliflozin): These drugs must be stopped at the first sign of illness. They work by flushing sugar out through urine, which also pulls water with it. When you’re already dehydrated from vomiting or fever, this can trigger euglycemic DKA-dangerously high ketones even when your blood sugar looks normal. The FDA flagged this in 2021 after reviewing over 1,200 cases. Don’t wait for symptoms. Stop these meds the moment you feel unwell.
- ACE inhibitors and ARBs (like lisinopril, losartan, valsartan): These blood pressure meds protect your kidneys-but only when you’re hydrated. If you’re drinking less than 1,500 mL (about 6 cups) a day, pause them. A 2022 meta-analysis found that stopping these during dehydration cuts AKI risk by 40%. Many people don’t realize their blood pressure pill is also a kidney risk during illness.
Insulin is different. You almost always need to keep taking it-even more than usual. Type 1 patients should increase their basal insulin by 10-20% every 4 hours if blood sugar stays above 15 mmol/L (270 mg/dL). Type 2 patients on insulin often need higher doses too. One 2023 study found that 68% of type 2 patients needed more insulin during illness, not less.
What to Do Instead: Monitoring, Hydration, and When to Call for Help
Stopping meds is only half the battle. You also need to monitor, hydrate, and know when to get help.- Check blood sugar every 2-4 hours. That’s at least 6 times a day. Don’t wait until you feel bad. Set phone alarms. Write down each reading. The target during illness is 100-180 mg/dL (5.6-10 mmol/L). Going higher than 240 mg/dL (13.3 mmol/L) means it’s time to test for ketones.
- Test for ketones if blood sugar is above 240 mg/dL. Use urine strips or a blood ketone meter. Blood ketones above 0.6 mmol/L or urine ketones above 1.5 mmol/L mean you’re at risk for DKA. Don’t ignore this. Call your doctor or go to the ER.
- Drink fluids constantly. Aim for at least 1,500 mL (6 cups) a day. Water, sugar-free electrolyte drinks, or broth are best. Avoid sugary sodas unless you’re treating low blood sugar. Dehydration is the silent trigger for both DKA and AKI.
- Don’t skip meals. Even if you’re nauseous, try to eat small amounts of carbs: toast, crackers, soup, or applesauce. Your body still needs fuel. If you can’t eat, sip on carbohydrate-containing drinks like regular soda or juice (15g carbs every hour if needed).
- Know the emergency signs: Vomiting for more than 4 hours, diarrhea for over 6 hours, ketones that don’t go down after 2 hours of fluids, or blood sugar below 70 mg/dL that doesn’t improve after 15g carbs. These are red flags. Don’t wait. Call 911 or go to the nearest emergency room.
Conflicting Advice? You’re Not Alone
One of the biggest problems? Doctors don’t all agree. The American Diabetes Association says you can keep metformin during mild illness if you’re hydrated. The International Diabetes Federation says stop it at the first sign of sickness. Your endocrinologist says one thing. Your GP says another. A 2024 survey found that 41% of patients got conflicting advice from different providers.And then there’s the Joslin Diabetes Center’s advice: “Always take your diabetes medicine unless your provider tells you not to.” That’s dangerously vague. It ignores the fact that some meds can kill you if taken during illness.
Don’t rely on memory or guesswork. Write down your own sick day plan-based on your specific meds-and keep it with your glucose meter.
Build Your Sick Day Kit Now
Don’t wait until you’re sick to prepare. Do it now, before flu season hits.Your kit should include:
- Glucose meter with 50+ test strips
- Ketone strips (urine or blood-have both if you can)
- 7-day supply of all your medications (including insulin)
- 6 bottles of sugar-free drinks (water, electrolyte solutions like Nuun)
- 10 packets of electrolyte replacement powder
- 15g carb snacks (glucose tablets, juice boxes, honey packets)
- Printed copy of your sick day plan (with doctor’s contact info)
Keep it in an easy-to-find spot. Many patients who survived serious illness say their kit saved them. One user on Reddit said, “I had the kit ready. When I got sick, I didn’t panic. I knew exactly what to do.”
What’s Missing From the Guidelines
The current rules work well for healthy, younger people with type 1 diabetes. In fact, following them reduces DKA risk by 73%. But they fall apart for older adults, people with kidney disease, heart failure, or multiple medications.A 2023 study in the Journal of the American Geriatrics Society found that 31% of elderly patients still had complications-even when they followed all the rules. Why? Because guidelines treat everyone the same. A 300mg daily dose of metformin isn’t the same risk as 2,000mg. A person with stage 3 kidney disease needs different rules than someone with healthy kidneys.
Experts are calling for personalized sick day plans. One doctor put it bluntly: “We’re still using a one-size-fits-all checklist in a world of complex, aging patients.”
Until then, your best tool is knowledge-and a written plan.
Final Checklist: Your Sick Day Action Plan
Before you get sick, write this down and keep it with your kit:- Which meds do I stop? (Metformin? SGLT2 inhibitors? ACE/ARBs?)
- Which meds do I keep? (Insulin? GLP-1 agonists? Sulfonylureas?)
- What’s my target blood sugar range during illness?
- When do I test for ketones? (Answer: Always when blood sugar >240 mg/dL)
- How much fluid should I drink? (At least 1,500 mL/day)
- What are my emergency signs? (Vomiting >4h, ketones >0.6 mmol/L, blood sugar <70 mg/dL not improving)
- Who do I call? (Endocrinologist, primary care, ER)
Review this list every 6 months. Update it after every doctor visit. If you’re unsure about any medication, ask your provider to write it down. Don’t assume they’ll remember. You’re the one who has to live with the consequences.
Illness doesn’t care how well you manage your diabetes on good days. It only cares about what you do when you’re vulnerable. Get ready now. Your future self will thank you.
Should I stop my metformin if I have a fever?
Yes. If you have a fever, vomiting, or diarrhea, stop metformin immediately. These conditions increase your risk of lactic acidosis, especially if you’re dehydrated. Even if your blood sugar is normal, the medication can become dangerous. Restart it only after you’ve been eating and drinking normally for 24-48 hours-and only after checking with your doctor.
Can I still take insulin when I’m sick?
Yes, and you may need more. Your body needs insulin even when you’re not eating. Skipping insulin during illness can trigger DKA, even in type 2 diabetes. Most people need to increase their insulin dose by 10-20% every 4 hours if blood sugar stays above 270 mg/dL. Always follow your provider’s specific plan.
What if my blood sugar is low when I’m sick?
Treat it like any low-15g fast-acting carbs (glucose tablets, juice, honey), then wait 15 minutes. Recheck. If it’s still low, repeat. Don’t wait to eat because you’re nauseous. If you can’t keep food down, sip sugary drinks slowly. Low blood sugar during illness is dangerous because your body can’t recover properly. If you can’t raise it after two attempts, call for help.
Do I need to test ketones if I have type 2 diabetes?
Yes-if your blood sugar is above 240 mg/dL. People with type 2 can develop euglycemic DKA, especially if they’re on SGLT2 inhibitors. Ketones don’t always show up with high blood sugar. If you’re vomiting, have a fever, or feel unusually tired, test for ketones even if your sugar looks okay.
How do I know if I’m dehydrated?
Signs include dry mouth, dark yellow urine, dizziness, or not peeing for 8+ hours. You might also feel unusually tired or confused. If you’ve been vomiting or have diarrhea, assume you’re dehydrated-even if you don’t feel it. Drink fluids slowly and steadily. Don’t wait for thirst. Keep track of how much you’re drinking. Less than 6 cups a day means you’re at risk.
What to Do Next
If you haven’t made a sick day plan yet, do it today. Print out the ADA’s free Sick Day Log. Call your doctor and ask: “Which of my meds do I stop when I’m sick?” Get it in writing. Keep your kit stocked. Practice checking ketones now, so you’re not fumbling when you’re sick.Diabetes doesn’t take a sick day. Neither should you. Being prepared isn’t just smart-it’s life-saving.
Eric Healy
November 18, 2025 AT 22:11metformin stop when sick?? bro i been takin it for 8 years n never stopped even when i had the flu. my doc said if u can keep fluids down its fine. why do people overcomplicate this??
Shannon Hale
November 20, 2025 AT 16:44OMG THIS IS SO IMPORTANT. WHY ISN’T THIS TAUGHT IN HIGH SCHOOL?? SGLT2 inhibitors are silent killers during illness. I lost my cousin to euglycemic DKA because he kept taking dapagliflozin ‘because his sugars were normal.’ NORMAL ISN’T SAFE WHEN KETONES ARE RISING. STOP THIS NOW.
Holli Yancey
November 21, 2025 AT 18:47I appreciate the detailed breakdown. I’ve been on metformin and lisinopril for years, and honestly, I never realized my BP med could hurt my kidneys when I’m dehydrated. I’m printing this out and putting it in my diabetes kit right now. Thank you for making it so clear.
Gordon Mcdonough
November 22, 2025 AT 21:25Jessica Healey
November 23, 2025 AT 04:55soooo i just stopped my canagliflozin last week when i got a cold and my sugar went from 130 to 280 in 6 hours. i was so scared. i thought i was dying. then i remembered this article and started checking ketones. turned out i had trace ketones. i drank 3 liters of water and my sugar came down. THANK YOU. i’m never ignoring this again.
Levi Hobbs
November 24, 2025 AT 15:51Great post. I’ve been a type 2 on insulin for 12 years and I’ve learned the hard way that you need more insulin when sick, not less. I used to cut back out of fear of highs - big mistake. My numbers were worse. Now I follow the 10-20% increase rule and it’s saved me from the hospital twice. Also, the sick day kit? Absolute game changer. I keep mine in the fridge next to the orange juice.
henry mariono
November 26, 2025 AT 02:26Just wanted to say thank you. I’m 68 and have CKD stage 3. I’ve been on metformin and losartan for years. This is the first time I’ve seen someone address the real risk for older adults with comorbidities. I’m updating my plan today. I’ll keep the kit by my bed.
Sridhar Suvarna
November 27, 2025 AT 13:46Joseph Peel
November 28, 2025 AT 17:56As someone who’s worked in emergency medicine for 15 years, I can tell you - DKA and AKI from poorly managed illness are the most preventable hospital admissions in diabetic patients. Yet they happen every single week. This is a textbook example of how fragmented care kills. Everyone needs a printed plan. No exceptions.
Elia DOnald Maluleke
November 30, 2025 AT 16:06It is not merely a medical issue - it is a philosophical one. We have entrusted our bodies to algorithms, to guidelines, to doctors who have never met us - yet we are expected to survive the storm with a checklist. The human body does not obey bullet points. It whispers before it screams. And we, in our haste to follow rules, forget to listen. Perhaps the real sick day plan is not in the kit - but in the quiet act of paying attention.
satya pradeep
November 30, 2025 AT 17:00My 72-year-old mom has type 2, CKD, and heart failure. She’s on metformin, lisinopril, and semaglutide. I just called her doctor and he said ‘just keep taking everything unless she’s vomiting.’ I showed him this article. He paused. Then said ‘you’re right. I’ve never thought about the combo.’ We’re making her a kit tonight. This isn’t just advice - it’s a lifeline.
saurabh lamba
December 1, 2025 AT 23:49bro i just read this while lying on the couch with a fever… and i stopped my dapagliflozin. i’m drinking water. i’m checking ketones. i didn’t panic. thanks. 🙏