Temporarily withhold the SGLT2 inhibitor in a dehydrated patient until volume status is restored.
In patients presenting with acute dehydration, SGLT2 inhibitors should be temporarily discontinued as part of "sick day" management and restarted once the patient is eating and drinking normally and volume status is restored (typically within 24-48 hours). 1, 2, 3
Clinical Reasoning
The KDIGO 2022 guidelines explicitly state that "it is reasonable to withhold SGLT2i during times of prolonged fasting, surgery, or critical medical illness (when patients may be at greater risk for ketosis)" 1. This recommendation is echoed across multiple high-quality guidelines 2, 4, 3, 5.
Why Stop During Dehydration?
The combination of dehydration and SGLT2 inhibitor use creates a perfect storm for serious complications:
Volume depletion risk: SGLT2 inhibitors cause osmotic diuresis (losing ~80g glucose/day in urine with accompanying water loss). When combined with existing dehydration from illness, this compounds hypovolemia 1, 6
Euglycemic diabetic ketoacidosis (DKA): Dehydration is a key precipitant for SGLT2i-associated DKA. Research demonstrates that dehydration plus insulinopenia are necessary and sufficient to trigger euglycemic ketoacidosis with these agents 7. The stress response from dehydration increases catecholamines and cortisol, promoting lipolysis and ketogenesis 7
Acute kidney injury concerns: While SGLT2 inhibitors don't typically cause AKI, it is prudent to discontinue during acute renal events or hypovolemia 8
Practical Management Algorithm
At Presentation:
- Stop the SGLT2 inhibitor immediately upon recognizing dehydration
- Assess severity of dehydration (vital signs, orthostasis, mucous membranes, skin turgor)
- Check blood or urine ketones - critical because DKA can occur with normal glucose (150-250 mg/dL range) 9, 4
- Evaluate for DKA symptoms: nausea, vomiting, abdominal pain, weakness, confusion 6, 4
During Treatment:
- Restore volume status with appropriate IV or oral fluids
- If concurrent diuretic use, consider reducing or holding diuretics 1, 2
- Monitor electrolytes and renal function
- Continue other diabetes medications with appropriate adjustments (reduce insulin/sulfonylureas if glucose is low; increase insulin 10-20% if glucose is elevated) 3
When to Restart:
Resume SGLT2 inhibitor when ALL of the following are met 1, 3, 5:
- Patient eating and drinking normally
- Volume status restored (no orthostasis, adequate urine output)
- Symptoms of acute illness resolved
- Blood ketones <0.6-1.0 mmol/L (if measured)
- Typically 24-48 hours after symptom resolution 1, 3
Common Pitfalls to Avoid
Don't confuse this temporary hold with permanent discontinuation: The 2022 KDIGO guidelines emphasize that once initiated, SGLT2 inhibitors should generally be continued even when eGFR falls below 20 mL/min/1.73 m² for their cardiovascular and renal protective benefits 1. The hold during acute illness is temporary and reversible.
Don't assume normal glucose rules out DKA: SGLT2i-associated DKA is often euglycemic (glucose <200 mg/dL), making it easy to miss. Always check ketones in symptomatic patients 9, 6, 4.
Don't restart too early: Ensure the patient is truly stable and volume-replete. Premature restart risks recurrent decompensation 5.
Patient Education
Provide written "sick day rules" 3, 5:
- Stop SGLT2 inhibitor during vomiting, diarrhea, or inability to maintain oral intake
- Continue drinking fluids (aim for 150-200 mL/hour if possible)
- Monitor glucose and ketones more frequently
- Seek medical attention early for persistent symptoms
- Know that DKA symptoms can occur even with normal blood sugars
Special Considerations
If patient has heart failure: While there are concerns about worsening heart failure with SGLT2i cessation 10, the acute risk of ketoacidosis and volume depletion during dehydration outweighs this concern. The temporary hold (24-48 hours) is unlikely to cause significant heart failure decompensation.
Perioperative context: For elective procedures, stop SGLT2 inhibitors the day before surgery (minimum 36-48 hours before procedure) 5. For emergency surgery in a dehydrated patient, the drug should already be held.