What is Farxiga (dapagliflozin)?

What is Farxiga (Dapagliflozin)?

Farxiga (dapagliflozin) is an oral SGLT2 inhibitor medication that blocks glucose reabsorption in the kidneys, approved for multiple indications including chronic kidney disease, heart failure (both reduced and preserved ejection fraction), type 2 diabetes with cardiovascular disease or risk factors, and glycemic control in type 2 diabetes. 1

Mechanism of Action

Dapagliflozin works by inhibiting sodium-glucose cotransporter-2 (SGLT2) in the proximal renal tubules, which normally reabsorbs about 90% of filtered glucose 1. By blocking this transporter, dapagliflozin:

• Promotes urinary glucose excretion (approximately 70 grams per day at therapeutic doses)
• Reduces sodium reabsorption and increases sodium delivery to the distal tubule
• Lowers cardiac preload and afterload through volume effects
• Decreases intraglomerular pressure via tubuloglomerular feedback
• Reduces sympathetic nervous system activity 1

Importantly, these effects occur independent of insulin secretion or action, making dapagliflozin effective across a broad range of patients 2, 1.

FDA-Approved Indications

The medication has four distinct approved uses 1:

1. Chronic Kidney Disease (CKD)

• Reduces sustained eGFR decline, end-stage kidney disease, cardiovascular death, and heart failure hospitalization
• Approved for adults with CKD at risk of progression
• Not recommended for polycystic kidney disease or patients requiring immunosuppressive therapy

2. Heart Failure (Any Ejection Fraction)

• Reduces cardiovascular death, heart failure hospitalization, and urgent heart failure visits
• Effective in both HFrEF (ejection fraction ≤40%) and HFpEF (ejection fraction >40%) 3, 4
• Benefits occur regardless of diabetes status 5, 6

3. Type 2 Diabetes with Cardiovascular Disease/Risk Factors

• Reduces heart failure hospitalization in patients with established cardiovascular disease or multiple risk factors
• Does not require active heart failure diagnosis 7

4. Glycemic Control in Type 2 Diabetes

• Adjunct to diet and exercise in adults and children ≥10 years old
• Not effective for glycemic control when eGFR <45 mL/min/1.73 m² due to mechanism of action 1

Dosing and Administration

Standard dose: 10 mg orally once daily 7

• Can be taken with or without food (food decreases peak concentration by 50% but doesn't affect total absorption) 1
• Maximum plasma concentration reached within 2 hours
• Half-life approximately 18 hours 8
• No dose adjustment needed for renal or hepatic impairment when used for cardiovascular/renal indications 1

Key Dosing Considerations:

• For glycemic control alone (without CV disease/risk factors): not recommended if eGFR <45 mL/min/1.73 m² 1
• For CKD, heart failure, or CV risk reduction: can be initiated down to eGFR 25 mL/min/1.73 m² 9, 1
• Once started, continue until dialysis or transplantation even if eGFR declines below initiation threshold 2, 1

Clinical Trial Evidence

Heart Failure Trials

DAPA-HF trial (4,744 patients with HFrEF, 45% with diabetes) 5, 6:

• 26% reduction in cardiovascular death or worsening heart failure (HR 0.74)
• 30% reduction in heart failure hospitalization (HR 0.70)
• 18% reduction in cardiovascular death (HR 0.82)
• Benefits consistent with or without diabetes

DELIVER trial (6,263 patients with HFpEF, 44% with diabetes) 3:

• 18% reduction in cardiovascular death or heart failure hospitalization (HR 0.82)
• First SGLT2 inhibitor to show benefit in preserved ejection fraction

Diabetes Cardiovascular Outcomes

DECLARE-TIMI 58 (17,160 patients, 59% without established CVD) 10, 11:

• 27% reduction in heart failure hospitalization
• 17% reduction in cardiovascular death or heart failure hospitalization
• Benefits extended to primary prevention population

Chronic Kidney Disease

DAPA-CKD trial (4,304 patients with CKD, eGFR 25-75 mL/min/1.73 m²) 9:

• 44% reduction in sustained eGFR decline ≥50%, end-stage kidney disease, or renal/CV death (HR 0.56)
• 29% reduction in cardiovascular death or heart failure hospitalization (HR 0.71)
• 31% reduction in all-cause mortality (HR 0.69)

Safety Profile and Adverse Effects

Common Adverse Effects:

• Genital mycotic infections (10-15% in women, higher in uncircumcised men) 9, 6
  • Usually manageable with antifungal therapy without discontinuation
• Urinary tract infections (increased frequency) 2, 12
• Increased urination (due to glucosuria and osmotic diuresis) 1

Serious but Rare Adverse Effects:

Diabetic ketoacidosis (including euglycemic DKA) 2, 4:

• Discontinue 3-4 days before scheduled surgery
• Stop during critical illness or prolonged fasting
• Higher risk with insulin deficiency, pump malfunction, or severe carbohydrate restriction

Volume depletion/hypotension 2, 7:

• Monitor volume status, especially when initiating therapy
• Adjust other diuretics as needed
• Temporary eGFR decline up to 15% may occur (typically resolves in 1-3 months) 9

Fournier's gangrene (necrotizing fasciitis of perineum) 2:

• Extremely rare but requires prompt treatment if suspected

Contraindications:

• Type 1 diabetes (for any indication) 9, 1
• Dialysis or eGFR <25 mL/min/1.73 m² at initiation (though can continue if started earlier) 1
• Severe hypersensitivity to dapagliflozin 7

Practical Clinical Considerations

When to Initiate:

Start dapagliflozin early in eligible patients rather than waiting for maximal optimization of other therapies 9. The medication can be initiated:

• During acute heart failure hospitalization (safe and may expedite discharge) 13
• Alongside other guideline-directed medical therapy for heart failure 6
• In CKD patients down to eGFR 25 mL/min/1.73 m² 9

Monitoring:

• Renal function: Check within 1 week of initiation; expect possible temporary decline 9
• Volume status: Assess for dehydration, especially in elderly or those on diuretics 2
• Genital hygiene: Counsel patients on infection prevention 9
• Ketone monitoring: In high-risk situations (illness, fasting, surgery) 4

Drug Interactions:

Minimal CYP450-mediated metabolism means few significant drug interactions 1. Primary metabolism is via UGT1A9 glucuronidation 1.

Comparative Considerations

Among SGLT2 inhibitors, dapagliflozin has:

• Longer duration of action (18 hours) compared to empagliflozin, potentially contributing to more stable sodium diuresis and blood pressure effects 8
• Less urinary glucose excretion than canagliflozin but similar cardiovascular benefits 8
• Broadest FDA approval including both HFrEF and HFpEF indications 1

The cardiovascular and renal benefits appear to be a class effect across SGLT2 inhibitors, with consistent results seen with empagliflozin and canagliflozin in similar populations 2, 3, 4.