The SADMAN Rule: The Medication Safety Rule Every Patient Should Know
Millions of people in the UK take daily medications for conditions like high blood pressure, type 2 diabetes, and heart failure — often without realising that some of these medicines can become dangerous during a bout of illness. The SADMAN rule is a simple mnemonic that could protect your kidneys and your overall health when you are unwell. In this video, Worthing based GP Dr David Stokes breaks it down clearly.
What is the SADMAN Rule?
What is the SADMAN Rule?
SADMAN is a medical mnemonic used to identify a group of commonly prescribed medications that need to be temporarily stopped when you become acutely unwell — particularly when you are dehydrated, vomiting, or unable to drink fluids normally. The letters stand for:
| Letter | Drug Class | Common Examples |
|---|---|---|
| S | Sulphonylureas | Gliclazide, Glipizide |
| A | ACE Inhibitors | Ramipril, Lisinopril, Perindopril |
| D | Diuretics | Furosemide, Bendroflumethiazide |
| M | Metformin | Metformin (also Mineralocorticoid receptor blockers e.g. Spironolactone) |
| A | ARBs (Angiotensin Receptor Blockers) | Losartan, Candesartan, Valsartan |
| N | NSAIDs | Ibuprofen, Naproxen, Diclofenac |
Some versions of the mnemonic extend to SADMANS to also include SGLT2 inhibitors such as Dapagliflozin and Empagliflozin — a drug class Dr Stokes also covers in a separate video on this channel.
Why Do These Medications Become Dangerous When You Are Ill?
When you are sick — particularly with a vomiting bug, diarrhoea, or a fever that causes sweating — your body becomes dehydrated. This reduction in fluid volume affects how your kidneys filter and clear medications. The drugs in the SADMAN group are processed by the kidneys, and when kidney blood flow drops during dehydration, these medicines can accumulate to dangerous levels or directly worsen kidney function, leading to a condition called acute kidney injury (AKI).
The concern is not that these are bad drugs — they are prescribed for important reasons and deliver real benefits when taken as directed. The issue is that during an acute illness, the risk-benefit balance temporarily shifts, and continuing them can do more harm than good.
When Should You Stop SADMAN Medications?
As a general guide, if you are unable to maintain your normal fluid intake due to illness — for example because you are vomiting, have significant diarrhoea, or are simply too unwell to drink — you should consider pausing SADMAN medications for 24 to 48 hours and resuming them once you are eating and drinking normally again.
This is sometimes called “sick day guidance.” Many patients are never given this advice at the time their medication is started, which is exactly why knowing the SADMAN rule matters.
Should You Always Stop Them? When to Get Medical Advice
Not every episode of feeling unwell requires stopping your medications. If you are managing to drink fluids and are only mildly ill, it may be appropriate to continue as normal. However, if you are uncertain, or if your illness is more severe, always seek advice from a healthcare professional before stopping any prescribed medication. Some conditions — such as heart failure — require careful management even during illness, and stopping diuretics without guidance can carry its own risks.
This is precisely the kind of nuanced conversation that benefits from time with a GP who knows your full medical history.
A Note on Ibuprofen
It is worth highlighting that ibuprofen — widely available over the counter — is included in this group as an NSAID. Many people reach for ibuprofen when they are unwell to manage fever or pain, unaware that it can worsen kidney function during dehydration. Paracetamol remains a safer choice during an acute illness, particularly if you are already taking any of the other SADMAN medications.