Is Farxiga (dapagliflozin) safe for a patient with impaired renal function, specifically an estimated Glomerular Filtration Rate (eGFR) of 41?

Is Farxiga Safe at eGFR 41?

Yes, Farxiga (dapagliflozin) is safe to initiate and use at an eGFR of 41 mL/min/1.73 m², though not for glycemic control—it should be prescribed specifically for cardiovascular and renal protection. 1

Key Safety and Efficacy Considerations

eGFR Thresholds for Initiation

• Dapagliflozin can be safely initiated when eGFR ≥25 mL/min/1.73 m² for cardiovascular and renal protection, making an eGFR of 41 well within the safe range. 1, 2
• For glycemic control specifically, dapagliflozin should not be initiated when eGFR <45 mL/min/1.73 m² because glucose-lowering efficacy is significantly reduced due to its mechanism of action. 1, 2
• At eGFR 41, prescribe dapagliflozin 10 mg once daily for cardiovascular/renal protection, not for diabetes control. 1

Evidence Supporting Use at This eGFR Level

The DAPA-CKD trial provides robust evidence for safety and efficacy at your patient's eGFR level:

• Dapagliflozin reduced the primary composite outcome (≥50% sustained eGFR decline, end-stage kidney disease, or renal/cardiovascular death) by 39% (HR 0.61 [95% CI 0.51-0.72]) in patients with eGFR 25-75 mL/min/1.73 m². 1
• The renal-specific composite outcome was reduced by 44% (HR 0.56 [95% CI 0.45-0.68]). 1
• Cardiovascular death or heart failure hospitalization was reduced by 29% (HR 0.71 [95% CI 0.55-0.92]). 1

Expected Initial eGFR Changes

Anticipate a transient, reversible eGFR decrease of 3-5 mL/min/1.73 m² within the first 1-4 weeks, which represents hemodynamic adjustment rather than kidney injury. 1, 3

• This initial dip is actually associated with better long-term renal outcomes—patients with a deeper initial dip had slower subsequent eGFR decline (-1.58 vs -2.44 mL/min/1.73 m²/year). 1
• After this initial dip, dapagliflozin significantly slows the rate of eGFR decline compared to placebo (-1.09 vs -2.85 mL/min/1.73 m² per year, p<0.001). 4
• Check eGFR and creatinine within 1-2 weeks after initiation to document this expected change. 1

Critical Safety Monitoring

Volume Status Assessment:

• Assess volume status before starting dapagliflozin and correct any volume depletion. 1
• Consider reducing concurrent loop or thiazide diuretic doses to prevent excessive volume depletion, especially in elderly patients or those already on diuretics. 1, 5
• Monitor for orthostatic lightheadedness or signs of volume depletion, particularly in the first few weeks. 5

Hypoglycemia Risk Management:

• If the patient is on insulin or sulfonylureas, reduce sulfonylurea dose by 50% or discontinue if already on minimal dose, and/or reduce total daily insulin dose by 20%. 5
• The risk of hypoglycemia is not significantly increased when dapagliflozin is added to patients not taking insulin or sulfonylureas. 5

Sick Day Rules (Critical Patient Education)

Instruct the patient to stop dapagliflozin immediately during any acute illness, particularly with:

• Reduced food or fluid intake 1
• Fever, vomiting, or diarrhea 1
• Any illness requiring hospitalization 1

Monitor for euglycemic diabetic ketoacidosis (DKA), which can occur even with normal blood glucose levels—check blood or urine ketones if the patient develops malaise, nausea, or vomiting. 1

Withhold dapagliflozin at least 3 days before major surgery or procedures requiring prolonged fasting to prevent postoperative ketoacidosis. 1

Additional Safety Considerations

• Genital mycotic infections occur in approximately 6% of patients (vs 1% on placebo)—counsel about daily hygienic measures. 1
• Urinary tract infections are more common with SGLT2 inhibitors. 1
• Rare but serious: necrotizing fasciitis of the perineum (Fournier gangrene) requires prompt treatment if suspected. 1

Continuation as eGFR Declines

If eGFR falls below 25 mL/min/1.73 m² during treatment, dapagliflozin 10 mg daily may be continued until dialysis is initiated. 1, 2

Patients who experienced deterioration of eGFR to <25 mL/min/1.73 m² in the DAPA-HF and DELIVER trials still benefited from continuation of dapagliflozin (HR 0.53 [95% CI 0.33-0.83]) with no excess safety outcomes. 6

Common Pitfall to Avoid

Do not discontinue dapagliflozin solely because eGFR falls below 45 mL/min/1.73 m²—cardiovascular and renal protective benefits persist even when glycemic efficacy is lost. 1