A patient with chronic kidney disease on an ACE inhibitor or angiotensin receptor blocker, a diuretic, metformin and an SGLT2 inhibitor is stable until they get gastroenteritis, and then the combination becomes the problem: reduced intake, volume depletion, and four drugs that each make acute kidney injury or metabolic complication more likely.
The intervention is a written list, handed over at the time of prescribing, naming the drugs to stop during any illness with vomiting, diarrhoea, fever or reduced oral intake, and saying when to restart and when to seek help. It should name the drugs the patient actually takes, by the brand on their strip, because a list that says 'diuretics' is not usable by someone holding a box marked torsemide.
Add the SGLT2 inhibitor-specific instruction: stop during acute illness, prolonged fasting or before surgery, and seek help for nausea, vomiting or abdominal pain even when the glucose reading is normal. Euglycaemic ketoacidosis is the failure mode that gets missed, and it gets missed because everyone checks the glucose.
- Write the list at prescribing, using the names on the patient's own strips
- Name the illness triggers concretely: vomiting, diarrhoea, fever, not eating or drinking
- State when to restart — usually 24 to 48 hours after eating and drinking normally
- Include the SGLT2 inhibitor rule for fasting and surgery
- Tell the patient a normal glucose does not exclude ketoacidosis on these drugs
Why it matters
The drugs that protect the kidney over years are the ones that damage it over three days of vomiting.
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