Dapagliflozin

Your kidneys filter approximately 180 grams of glucose (sugar) from the blood each day, then reabsorb nearly all of it back into the bloodstream ^{[1, 2]}. A protein called SGLT2 (sodium-glucose cotransporter 2), located in the proximal tubule of the kidney, is responsible for reabsorbing about 90% of this filtered glucose ^{[1, 3]}.

Dapagliflozin blocks SGLT2, preventing the kidneys from reabsorbing glucose ^{[1, 2]}. The unabsorbed glucose is then excreted in the urine (glycosuria), lowering blood sugar levels. This mechanism is independent of insulin, making it effective regardless of beta-cell function or insulin resistance.

Beyond glucose control, dapagliflozin has remarkable cardiovascular and kidney benefits ^{[4, 5, 6]}:

Heart failure: The DAPA-HF trial showed dapagliflozin reduced the combined risk of cardiovascular death or worsening heart failure by 26% in patients with heart failure and reduced ejection fraction — whether or not they had diabetes ^[4]. The DELIVER trial extended this to heart failure with preserved ejection fraction ^[7].

Kidney disease: The DAPA-CKD trial showed dapagliflozin reduced the risk of sustained decline in kidney function, end-stage kidney disease, or renal/cardiovascular death by 39% in patients with chronic kidney disease ^[5].

These benefits are thought to involve multiple mechanisms: reduced intraglomerular pressure (via tubuloglomerular feedback), mild diuresis and natriuresis, reduced cardiac preload and afterload, improved myocardial energy metabolism (shift to ketone utilization), and anti-inflammatory effects ^{[3, 6]}.

When starting dapagliflozin, effects develop over the first few weeks ^{[1, 2]}.

First few days: You may notice increased urination and thirst — this is expected and is part of how the drug works (excreting glucose in the urine also draws water). Stay well hydrated.

First 1-4 weeks: Blood sugar levels gradually improve. You may notice modest weight loss (1-2 kg) from the caloric loss through urinary glucose excretion and mild diuresis.

For heart failure: Symptom improvement (less shortness of breath, less edema) may begin within the first 2-4 weeks. In the DAPA-HF trial, the benefit curve separated early ^[4].

Important — genital hygiene [1]: Dapagliflozin increases glucose in the urine, which can promote yeast infections. Both men and women should maintain good genital hygiene. Signs include itching, redness, or discharge in the genital area.

eGFR dip [1, 5]: Your kidney function tests may show a small decrease in eGFR in the first 2 weeks. This is an expected hemodynamic effect (not kidney damage) and should stabilize. Do not stop the medication based on this initial dip.

Stay hydrated: Drink adequate fluids, especially during hot weather, exercise, or illness.

Food [1]: Dapagliflozin can be taken with or without food. Food does not significantly affect its efficacy.

Alcohol [1]: Alcohol can increase the risk of dehydration and volume depletion when combined with dapagliflozin. Excessive alcohol may also increase the risk of ketoacidosis (DKA), especially in patients with type 1 diabetes or those on very low-carbohydrate diets. Limit alcohol to moderate amounts.

Hydration — IMPORTANT [1, 4]: Because dapagliflozin causes glucose and sodium excretion in the urine, adequate fluid intake is essential. Drink at least 8 glasses of water daily. Increase fluid intake during hot weather, exercise, or illness with vomiting/diarrhea.

Low-carbohydrate diets [1]: Exercise caution with very low-carbohydrate or ketogenic diets, as these may increase the risk of DKA when combined with SGLT2 inhibitors.

Type 2 diabetes [1, 2]: - Dose: 5 mg once daily in the morning; may increase to 10 mg once daily - Not recommended if eGFR <25 mL/min/1.73m2 for glycemic control (insufficient glucose filtration) - Can be used as monotherapy or in combination with other antidiabetic agents

Heart failure (HFrEF and HFpEF) [1, 4, 7]: - Dose: 10 mg once daily - Can be initiated regardless of diabetes status - Can be started in-hospital or outpatient - No need for dose titration - Can be used with eGFR as low as 25 mL/min/1.73m2 (per DAPA-HF and DELIVER)

Chronic kidney disease [1, 5]: - Dose: 10 mg once daily - Approved for patients with eGFR 25-75 mL/min/1.73m2 and albuminuria - Can continue even if eGFR falls below 25 mL/min during treatment - Do not initiate if eGFR <25 mL/min/1.73m2

No dose adjustment needed for hepatic impairment (mild-moderate) or elderly patients ^[1].

When to hold: During periods of acute illness, surgery, or prolonged fasting to reduce DKA risk ^[1].

Dapagliflozin (Farxiga) is currently available as brand-name only in the United States ^{[8, 9]}.

Pricing [8, 9]: - Brand Farxiga: approximately $500-600/month (list price) - With insurance: copay varies widely ($25-150/month depending on plan) - Manufacturer savings card: eligible patients may pay as little as $0/month

Cost-saving strategies [9]: - AstraZeneca savings card: FarxigaSavings.com — eligible commercially insured patients can reduce out-of-pocket costs significantly - Patient assistance program: AstraZeneca provides free medication to qualifying uninsured patients - GoodRx and RxAssist may identify additional discount programs - Check with your insurance — many plans now cover SGLT2 inhibitors due to strong clinical evidence for heart and kidney outcomes

Generic availability: Generic dapagliflozin is not yet available in the US as of 2026. Patent expiry is expected around 2025-2027; generic entry timing depends on litigation outcomes.

Pregnancy [1]: Dapagliflozin is not recommended during pregnancy, particularly during the second and third trimesters. Based on animal studies, dapagliflozin may affect renal development and maturation. SGLT2 is important for kidney development, and inhibition during critical periods could impair fetal kidney function.

There are no adequate human studies. Use effective contraception during treatment. If pregnancy is detected, discontinue dapagliflozin ^[1].

Breastfeeding [1, 10]: Dapagliflozin is present in rat milk. It is not known whether it is excreted in human breast milk. Because of the potential for adverse effects on the developing infant's kidneys, dapagliflozin is not recommended during breastfeeding ^[1].

As of 2026, dapagliflozin is available only as the brand product Farxiga in the United States ^{[8, 9]}.

Available formulations: - Farxiga tablets: 5 mg and 10 mg - No generic equivalent is currently available

Combination products: - Xigduo XR (dapagliflozin + metformin ER): Available in several strength combinations - Qternmet XR (dapagliflozin + saxagliptin + metformin ER)

Generic outlook: Patent protection extends into the mid-2020s. Generic entry may occur within the next few years, which would significantly reduce costs.