During a dehydrating illness with repeated vomiting or diarrhea, several common medications should be temporarily paused, including ACE inhibitors, ARBs, diuretics, metformin, SGLT2 inhibitors, and NSAIDs. Insulin is the main exception: you usually keep taking it. Restart the paused ones once you recover, and confirm with your doctor.
When a stomach bug, the flu, or food poisoning hits, your body loses a lot of fluid fast. Some of the everyday pills that keep you healthy can become risky during those few days. This guide is the plain-English version of what doctors call "sick day rules." It walks through which medicines to hold, the one to keep taking, and how to safely restart everything when you feel better.
This is a Tier 2 overview. For drug-specific steps, follow the links to each detailed guide as you read.
Why dehydration changes the rules
When you cannot keep fluids down, your blood volume drops. Your kidneys, which normally filter waste smoothly, suddenly have much less fluid to work with. Several common medications either lean on your kidneys or change your fluid and blood sugar balance, so they can do harm when you are dried out instead of help.
A group of kidney and diabetes experts looked at this exact problem and reached agreement on a short list. In a modified Delphi consensus study, they concluded that "renin-angiotensin system inhibitors, diuretics, nonsteroidal anti-inflammatory drugs, sodium/glucose cotransporter 2 inhibitors, and metformin should be temporarily stopped" during a dehydrating illness. That is the backbone of every sick day list.
Blood pressure pills like ACE inhibitors and ARBs are a good example of why. Normally, when your blood volume drops, your body makes more of a hormone that helps your kidneys hold onto fluid. These medicines blunt that response on purpose to lower blood pressure. As one review of sick day guidance explains, "since the normal physiological response to hypovolaemia is impaired by ACE inhibitors and sartans, patients taking these drugs are at increased risk of acute kidney injury." In short, the same effect that helps on a normal day can backfire when you are very dehydrated.
You may see this list taught as the SADMANS sick day rule. It is a memory trick for the drug groups to pause: Sulfonylureas, ACE inhibitors, Diuretics, Metformin, ARBs, NSAIDs, and SGLT2 inhibitors. The table below turns that into something you can actually scan.
The sick day medication table
Here is which common drug groups to hold and which to keep, with the reason for each. Examples are listed to help you recognize your own pills, not as medical advice about your specific prescription.
| Drug group (examples) | Hold or continue | Why |
|---|---|---|
| ACE inhibitors (lisinopril) | Hold | Can strain the kidneys when you are dehydrated |
| ARBs (losartan) | Hold | Same kidney risk as ACE inhibitors |
| Diuretics (furosemide, hydrochlorothiazide) | Hold | Add to fluid loss when you are already losing fluid |
| Metformin | Hold | Dehydration raises the risk of a rare acid buildup |
| SGLT2 inhibitors (Jardiance) | Hold | Raise the risk of a dangerous ketone buildup when ill |
| NSAIDs (ibuprofen) | Hold | Can reduce blood flow to stressed kidneys |
| Sulfonylureas (glipizide) | Hold | Can push blood sugar too low when you are not eating |
| Insulin | Continue | Stopping it is dangerous; keep taking it and check ketones |
For the blood pressure groups in the table, see blood pressure meds and sick day rules for the full hold-and-restart steps. If you take a sulfonylurea such as glipizide, the sulfonylurea sick day guide covers when low blood sugar is the bigger risk.
The insulin exception: do not stop it
This is the most important line in this whole guide. If you take insulin, do not stop it just because you are sick or not eating much. Your body still needs it, and illness can actually push your blood sugar up.
The CDC's sick day guidance is direct: "continue taking your insulin and diabetes pills as usual." It also advises watching for ketones when blood sugar runs high: "you can use an over-the-counter kit to test your urine for ketones. If ketones are present, call your doctor right away."
So insulin sits in its own column. Pause the kidney and dehydration-sensitive pills above, but keep your insulin going and check ketones as your care team has shown you. For more detail, read taking insulin when sick and not eating. And if you take a diabetes pill in the SGLT2 group, the steps differ from insulin, so see sick day rules for Jardiance and sick day rules for metformin.
When to hold, when to restart, when to call
Sick day rules are short and simple once you see the pattern. Use this as your playbook, and remember that guidance does vary from source to source, so your own doctor's advice always wins.
When to hold. Start holding the listed pills when you have repeated vomiting, frequent diarrhea, or heavy sweating and fevers that keep you from drinking and holding down fluids. Mild symptoms where you are still drinking normally usually are not a reason to pause anything. When in doubt, ask.
When to restart. Restart the paused medicines once you are eating and drinking normally again. Many guides suggest waiting until you have been well for a stretch. One review of sick day cards describes the practice of withholding "specific medications until after 24-48 h of being well again." That same review is honest that the field has "inconsistencies in recommendations" and "little evidence," which is exactly why you should confirm your own restart day with a professional rather than guess.
When to call or seek care. Reach out to your doctor or pharmacist if you cannot keep any fluids down, if you are not improving after a day or two, if you pass very little urine, or if you feel dizzy, confused, or extremely weak. If you take a diabetes medicine and have ketones, call right away. These are not the moments to wait it out.
If you are also low on a prescription during all of this, running out of medication before a refill covers how to bridge the gap safely. And for the medicines that should never be paused on a whim, see medications you should never skip. If a dose comes back up shortly after you swallow it, what to do when you vomit after taking medication walks through whether to redose.
How Pillo helps
The hard part of sick day rules is not knowing them. It is remembering to switch your routine off, then switching it back on for every single pill once you recover. That is a lot to track when you feel awful.
Pillo (Android) makes that part easy. You can pause the specific medications you are holding so they stop nagging you while you are sick, then set a clear reminder to restart each one when you are well. Because Pillo uses a persistent alarm that keeps going until you confirm you took your dose, the restart will not get lost in the shuffle. If you manage medicines for a parent, partner, or another dependent, you can run each person's schedule and pause-and-restart inside your own app, so nobody's blood pressure pill quietly stays off for a week.
Pillo does not give medical advice or decide which pills to hold. You and your care team make that call. Pillo just makes sure the plan actually happens.
Frequently asked questions
What does SADMANS stand for?
SADMANS is a memory aid for the medication groups to pause during a dehydrating illness: Sulfonylureas, ACE inhibitors, Diuretics, Metformin, ARBs, NSAIDs, and SGLT2 inhibitors. The same short list appears in the expert consensus on sick day medications, which names renin-angiotensin system inhibitors, diuretics, NSAIDs, SGLT2 inhibitors, and metformin as drugs to temporarily stop.
Should I stop insulin when I am sick and not eating?
No. Insulin is the key exception to sick day rules. The CDC advises to "continue taking your insulin and diabetes pills as usual," and to check for ketones if your blood sugar runs high. Stopping insulin during illness can be dangerous, so keep taking it and follow your care team's plan.
When can I restart my medications after being sick?
Generally once you are eating and drinking normally again. A review of sick day guidance notes the practice of withholding medicines "until after 24-48 h of being well again," though it also points out that recommendations vary between sources. Confirm your exact restart day with your doctor or pharmacist.
Do I need to pause my pills for a mild cold?
Usually not. Sick day rules are about dehydration, meaning repeated vomiting, frequent diarrhea, or heavy fevers and sweating that keep you from drinking. If you are still eating and drinking normally with a mild cold, you typically keep taking everything as usual. Ask if you are unsure.
Should I stop metformin or my SGLT2 pill when I have a stomach bug?
During a dehydrating illness with vomiting or diarrhea, both metformin and SGLT2 inhibitors are usually held for a short time. Metformin is paused because dehydration raises the small risk of a rare acid buildup, and SGLT2 inhibitors are paused because illness can raise the risk of a dangerous ketone buildup. For the step-by-step plan on each, see sick day rules for metformin and sick day rules for Jardiance, and confirm the timing with your doctor or pharmacist.
Why do blood pressure pills need to be paused?
Because they can stress your kidneys when you are dehydrated. As one sick day review explains, "since the normal physiological response to hypovolaemia is impaired by ACE inhibitors and sartans, patients taking these drugs are at increased risk of acute kidney injury." The same effect that lowers blood pressure on a normal day can backfire when blood volume is low.
This article is for general information and is not medical advice. Sick day rules vary from person to person and source to source. Consult your doctor or pharmacist for advice specific to your medications before holding or restarting anything.
