When should Sodium-Glucose Transporter 2 (SGTL2) inhibitors be held before surgery?

SGLT2 Inhibitor Management Before Surgery

SGLT2 inhibitors should be discontinued 3-4 days before elective surgery to reduce the risk of perioperative metabolic acidosis. 1

Specific Timing Recommendations by Medication

• Canagliflozin, dapagliflozin, and empagliflozin: Discontinue ≥3 days before scheduled surgery
• Ertugliflozin: Discontinue ≥4 days before scheduled surgery

Rationale for Discontinuation

SGLT2 inhibitors increase the risk of perioperative complications, particularly euglycemic diabetic ketoacidosis (euDKA), which can occur even with normal blood glucose levels. This risk is heightened during the surgical period due to:

1. Fasting state
2. Surgical stress
3. Increased counterregulatory hormones
4. Reduced insulin levels

The 2024 AHA/ACC guidelines provide a Class 1 recommendation (strong) with moderate-quality evidence supporting this practice 1. The American Diabetes Association similarly recommends discontinuing SGLT2 inhibitors 3-4 days before surgery 1.

Special Considerations

Emergency Surgery

For patients on SGLT2 inhibitors requiring emergency surgery:

• Measure both blood glucose and blood ketone levels on admission
• Proceed with surgery if the patient is clinically well and ketones are <1.0 mmol/L
• Consider glucose-containing IV fluids if prolonged fasting is anticipated 1
• Monitor closely for signs of metabolic acidosis

Heart Failure Patients

While SGLT2 inhibitors provide cardiovascular benefits for heart failure patients, the risk of perioperative euDKA outweighs the temporary loss of benefit from brief discontinuation 1.

Perioperative Management Algorithm

1. Preoperative (3-4 days before surgery)

   • Discontinue SGLT2 inhibitor
   • Continue other guideline-directed medical therapy for heart failure or diabetes
   • Ensure adequate hydration

2. Day of Surgery

   • Monitor blood glucose every 2-4 hours
   • Consider checking ketone levels if clinically indicated
   • Use short-acting insulin as needed for glycemic control

3. Postoperative

   • Resume SGLT2 inhibitor only when:
     • Patient is eating and drinking normally (usually 24-48 hours after surgery)
     • Capillary ketones are <0.6 mmol/L (if measured) 1

Common Pitfalls to Avoid

1. Inadequate discontinuation time: Case reports document euDKA occurring even when SGLT2 inhibitors were discontinued 48 hours before surgery 2. The 3-4 day recommendation provides a safer margin.

2. Failure to recognize euDKA: Unlike traditional DKA, euDKA presents with normal blood glucose levels (often <200 mg/dL), making diagnosis challenging. Monitor for:

   • Unexplained metabolic acidosis
   • Elevated anion gap
   • Ketosis
   • Clinical deterioration despite normal glucose readings

3. Overlooking non-diabetes indications: Remember that patients may be taking SGLT2 inhibitors for heart failure or chronic kidney disease even without diabetes 1.

The evidence strongly supports discontinuing SGLT2 inhibitors before surgery, with the most recent guidelines from major cardiovascular and diabetes organizations consistently recommending a 3-4 day preoperative discontinuation period to minimize the risk of potentially life-threatening euglycemic diabetic ketoacidosis.