Nursing care
SGLT2 Inhibitors: what to check before you give it
Written and reviewed by Dana Whitfield, RN, MSN · 5 min read · Updated September 2026
Short answer
SGLT2 inhibitors such as empagliflozin, dapagliflozin and canagliflozin lower blood glucose by blocking glucose reabsorption in the renal proximal tubule, so excess glucose is excreted in the urine. That glycosuria is also why genital fungal infections are so common on these drugs, and why ketones can rise dangerously even when blood glucose looks near-normal — euglycaemic diabetic ketoacidosis is the complication most likely to be missed.
What it does and why it is prescribed
SGLT2 inhibitors — empagliflozin, dapagliflozin, canagliflozin, ertugliflozin — block the sodium-glucose cotransporter 2 in the proximal renal tubule. Normally this transporter reabsorbs almost all filtered glucose back into the blood. Blocking it means glucose stays in the tubule and is excreted in urine instead, which lowers blood glucose independently of insulin.
They are prescribed for type 2 diabetes, and several agents now carry additional indications for heart failure and chronic kidney disease, reflecting cardiorenal benefits shown independent of glycaemic control. Because the mechanism is insulin-independent, they can be used alongside metformin, insulin or GLP-1 agonists, and the glucose lost in urine is a deliberate, expected effect of therapy rather than a side effect to correct.
Nursing considerations before giving it
Check renal function before the first dose and periodically thereafter — eGFR determines whether the drug is appropriate and at what dose, since these agents work on the nephron and are less effective as filtration falls. Confirm the patient is not volume depleted; SGLT2 inhibitors have a mild diuretic effect through osmotic glucose excretion, so dehydration, hypotension or recent diuretic escalation are worth reviewing before administration.
Ask about any history of recurrent genital or urinary infections, since glycosuria created by the drug feeds fungal and bacterial growth in that environment. Review the surgical calendar too: these agents are typically held for a period before scheduled surgery because of the ketoacidosis risk under the metabolic stress of fasting and anaesthesia. Confirm the patient is not on a very-low-carbohydrate or ketogenic diet, which compounds that same risk.
What to monitor
Monitor blood glucose as with any glucose-lowering agent, but do not rely on glucose alone to judge whether the drug is safe to continue. Watch volume status — postural blood pressure, weight, intake and output — because the osmotic diuresis can tip an older or diuretic-treated patient into hypovolaemia. Renal function is monitored on an ongoing basis, particularly around any acute illness.
Watch for genitourinary symptoms at every contact: itching, discharge, dysuria or perineal discomfort, since fungal infections related to glycosuria are common and patients do not always volunteer them. Most importantly, monitor for symptoms of ketoacidosis — nausea, vomiting, abdominal pain, fatigue, rapid breathing — regardless of what the glucose reading shows, and check ketones if these appear rather than waiting for hyperglycaemia to confirm suspicion.
Side effects versus adverse effects
Expected side effects follow directly from the mechanism: increased urination, mild weight loss, and genital fungal infections from the glucose-rich urine. These are common, generally manageable with hygiene teaching and antifungal treatment when needed, and are not usually a reason to stop the drug outright.
The adverse effect that matters most is euglycaemic diabetic ketoacidosis — ketoacidosis developing with blood glucose only mildly elevated or even normal, because the drug is actively clearing glucose from the blood while ketone production continues unchecked. This is easy to miss precisely because the glucose number looks reassuring. Other adverse effects include volume depletion severe enough to cause acute kidney injury or hypotension, and rarely necrotising fasciitis of the perineum (Fournier's gangrene), which needs urgent surgical referral.
What to hold for and when to call
Hold the dose and notify the prescriber for any symptoms suggestive of ketoacidosis — nausea, vomiting, abdominal pain, unusual fatigue, or laboured breathing — even with a normal or only slightly raised glucose, and check a ketone level. Hold before scheduled surgery or a prolonged fasting period, per the surgical or procedural protocol in use, because of the same risk under metabolic stress.
Hold and escalate for signs of significant dehydration, a marked drop in blood pressure, or a sharp rise in creatinine, particularly during acute illness, vomiting, diarrhoea or reduced oral intake — sick-day guidance for these drugs typically means stopping temporarily. Call promptly for perineal pain, swelling or systemic illness out of proportion to a simple fungal infection, since this can signal Fournier's gangrene and needs urgent assessment.
Patient teaching
Teach patients that increased urination and mild weight loss are expected, and that the drug works by passing glucose out through the urine, which explains why genital itching or discharge can appear even with good glucose control — this needs mentioning early so it doesn't come as a surprise. Cover genital hygiene, prompt reporting of fungal symptoms, and the fact that antifungal treatment usually resolves them without stopping the medication.
Teach sick-day rules explicitly: stop the medication during illness with vomiting, diarrhoea, reduced fluid intake or before surgery, and restart only once eating and drinking normally, per the prescriber's instructions. Make clear that nausea, vomiting or abdominal pain warrants urgent contact and ketone checking even if a home glucose reading looks fine, since a normal number does not rule out ketoacidosis on this drug class.
The next step on this is the same as on everything else here: answer questions and read the rationales. Our pharmacology practice questions are the closest set to what this page covers.
One question from the pharmacology set
A client with heart failure is started on furosemide 40 mg PO daily. Which findings should the nurse report to the provider before administering the next dose? Select all that apply.
Rationale
Furosemide is a loop diuretic, so the two things you are watching are potassium and kidney function. A potassium of 2.9 mEq/L is below the 3.5–5.0 reference range and puts the client at risk for dysrhythmia — hold and report. Muscle cramps with palpitations are the clinical face of that same hypokalemia, so they are reported together, not separately. A creatinine that doubles signals the diuresis has outrun renal perfusion. A blood pressure of 132/78 and a 1 kg loss are the expected response to the drug working, not reasons to hold it.
Answer: A, D, E
Common questions
Why do SGLT2 inhibitors cause genital fungal infections?
The drug blocks glucose reabsorption in the kidney, so glucose is deliberately excreted in the urine. That glucose-rich urine around the genital area creates an environment where yeast and, less often, bacteria thrive, making fungal infections one of the most common effects of this drug class.
What is euglycaemic DKA and why does it matter with SGLT2 inhibitors?
It is diabetic ketoacidosis occurring with blood glucose normal or only mildly raised, because the drug is clearing glucose from the blood while ketone production continues. It matters because glucose alone will not flag the problem — nausea, vomiting, abdominal pain or laboured breathing need a ketone check regardless of the glucose reading.
Should SGLT2 inhibitors be held before surgery?
Yes, typically held for a period before scheduled surgery according to facility or prescriber protocol, because fasting and surgical stress raise the risk of euglycaemic ketoacidosis. Confirm the specific hold interval with the surgical team rather than assuming a fixed number of days applies everywhere.
Can SGLT2 inhibitors cause hypoglycaemia?
On their own, rarely, since the mechanism is insulin-independent. The risk rises when combined with insulin or a sulfonylurea, so monitor glucose more closely and review dosing of those other agents when starting an SGLT2 inhibitor alongside them.
What renal parameters matter most when giving an SGLT2 inhibitor?
eGFR before starting and periodically during treatment, since it determines eligibility and dosing, and creatinine or signs of acute kidney injury during illness or volume depletion. The drug's glucose-lowering effect diminishes as kidney function declines, even though some cardiorenal protective effects may persist.
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