Understanding Sick Day Rules: A Plain-English Explainer
Sick Day Rules: what it is, why it matters, and what published guidance actually asks of you.
Most avoidable acute kidney injury in the community happens when ordinary medicines are continued through a dehydrating illness.
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 speak to a doctor" below apply to you.
The short answer
What to do about regular medicines when you become acutely unwell.
Where it fits
This is part of Long Term Conditions. The published position is set out below, along with what it means day to day.
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 that means in practice
What that looks like in practice:
- 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 gets people into trouble
What to watch out for:
- Stopping insulin because you are not eating
- Continuing diuretics and ACE inhibitors while vomiting
Where to go next
- What the Guidance Really Says About Sick Day Rules
- The Sick Day Rules Checklist: What to Do and What to Skip
- Sick Day Rules — the reference entry
- Talking to Your Care Team: What the Evidence Actually Says
- What the Guidance Really Says About Benefits and Financial Support
When to speak to a doctor
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.
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