Starting an SGLT2 inhibitor or an ACE inhibitor or angiotensin receptor blocker lowers intraglomerular pressure, so eGFR often falls in the first few weeks. A dip of up to about 30% is expected and reflects the protective haemodynamic effect, not injury; long-term kidney outcomes are better despite it.
Recheck creatinine and potassium within two to four weeks of starting. A fall of more than 30%, or a continuing decline, calls for a look for volume depletion, NSAIDs, renal artery stenosis or another cause before the drug is blamed.
- Recheck creatinine and potassium two to four weeks after starting an SGLT2 inhibitor or RAAS blocker
- Accept an eGFR dip of up to about 30% without stopping the drug
- Look for volume depletion, NSAIDs or renal artery stenosis if the fall exceeds 30%
- Advise sick-day rules for both drug classes during vomiting, diarrhoea or poor intake
Why it matters
Stopping these drugs for an expected dip removes their long-term kidney protection.
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