Sick Day Rules
What to do about regular medicines when you become acutely unwell.
Last revised
Key takeaways
- Commonly paused: metformin, SGLT2 inhibitors, ACE inhibitors, ARBs, diuretics, NSAIDs
- Never stop: insulin, even if you are not eating
- Most useful single change: Ask for written sick day rules at your next review.
- Commonest mistake: Stopping insulin because you are not eating.
- See a doctor if any of the signs under "When to get help" below apply to you.
Why it matters
Most avoidable acute kidney injury in the community happens when ordinary medicines are continued through a dehydrating illness.
The numbers, in one place
| Measure | Figure |
|---|---|
| Commonly paused | metformin, SGLT2 inhibitors, ACE inhibitors, ARBs, diuretics, NSAIDs |
| Never stop | insulin, even if you are not eating |
| Steroids | usually need increasing, not stopping |
| Get rules in writing | before you need them |
What helps
- Ask for written sick day rules at your next review
- Keep fluids up and test more often if you have diabetes
- Contact your team early rather than waiting
What to avoid
- Stopping insulin because you are not eating
- Continuing diuretics and ACE inhibitors while vomiting
Where to go next
- Starting Out With Sick Day Rules
- Sick Day Rules: Common Questions Answered
- Talking to Your Care Team: What the Evidence Actually Says
- What the Guidance Really Says About Benefits and Financial Support
When to get help
Seek urgent help for persistent vomiting, passing much less urine, drowsiness or confusion during an illness. If you take steroids, seek emergency help for severe weakness, vomiting, abdominal pain or collapse — adrenal crisis is life-threatening. Carry a steroid emergency card.
Where this comes from
- Think Kidneys — sick day guidance
- Diabetes UK — sick day rules
How this page was put together
Every figure, recommendation and warning above is taken from the guidance named in Where this comes from. Nothing on this page is inferred, summarised or generalised beyond what those bodies publish: where they give a number, it is their number, and where they are silent, so are we. Pages are rebuilt whenever the underlying record changes. Sign-off by a named clinician, where it has happened, is shown at the top of the page along with the date.
Medical disclaimer
This article is general information, not medical advice. It cannot account for your own history, medication or circumstances. Always speak to a GP, pharmacist or another qualified health professional before making changes that affect your treatment, and never delay seeking medical advice because of something you have read here. In an emergency, call 999.