The short answer
Farxiga (dapagliflozin) and Jardiance (empagliflozin) belong to a class of medicines called SGLT2 inhibitors. They were originally developed as diabetes medicines, but their benefits extend beyond lowering blood sugar.
In appropriate people with chronic kidney disease (CKD), SGLT2 inhibitors can slow the loss of kidney function and reduce the risk of kidney disease progression. Importantly, these benefits can occur even in people who do not have diabetes. Large trials including DAPA-CKD and EMPA-KIDNEY demonstrated kidney benefits across patients with and without diabetes. (New England Journal of Medicine)
The title is therefore broadly correct, but calling Farxiga and Jardiance simply “diabetes drugs” is incomplete. They are now important kidney and cardiovascular medicines for selected patients with CKD.
How do SGLT2 inhibitors protect the kidneys?
SGLT2 is a protein in the kidney that normally helps reabsorb filtered glucose and sodium back into the blood.
SGLT2 inhibitors block this process. As a result:
More glucose + sodium remain in the urine → more sodium reaches the kidney’s sensing system → kidney filtration is adjusted downward → pressure inside the glomeruli decreases.
The glomeruli are the tiny filtering units of the kidneys. Excessive pressure inside them can contribute to ongoing kidney damage and albumin leakage.
This effect is different from simply lowering blood sugar. Research suggests that the kidney benefits of SGLT2 inhibitors are substantially related to their kidney and blood-flow effects, not just their glucose-lowering action. (New England Journal of Medicine)
Why can eGFR fall after starting one?
This is an important point because it can initially look alarming.
eGFR is an estimate of how well the kidneys filter blood. After starting an SGLT2 inhibitor, eGFR can show a small early decline because the medicine changes pressure and filtration within the kidney.
That early change is different from the gradual loss of kidney function that these medicines are intended to prevent.
Over the longer term, clinical trials have shown a slower rate of kidney-function decline with dapagliflozin and empagliflozin in appropriate CKD populations. (New England Journal of Medicine)
Therefore, a new eGFR should be interpreted alongside:
- the previous eGFR
- the size of the change
- when the medication was started
- hydration status
- blood pressure
- other medications
- recent illness
- serum creatinine and other relevant tests
One eGFR value does not tell the entire story.
Who can benefit?
SGLT2 inhibitors are not appropriate for every person with CKD, but current KDIGO guidance recommends them broadly in several groups.
Examples include people with:
- Type 2 diabetes and CKD with appropriate kidney function
- CKD with significant albuminuria
- CKD and heart failure, regardless of diabetes status
- Certain people with lower eGFR even when albuminuria is not high
KDIGO 2024 recommends SGLT2 inhibitor therapy for appropriate adults with CKD and an eGFR of at least 20 mL/min/1.73 m², with specific criteria depending on diabetes, albuminuria, and heart failure. (KDIGO)
Eligibility is not determined by eGFR alone. The cause of CKD, albuminuria, other diseases, medications, and tolerability also matter.
Farxiga vs Jardiance
| Farxiga | Jardiance | |
|---|---|---|
| Generic name | Dapagliflozin | Empagliflozin |
| Drug class | SGLT2 inhibitor | SGLT2 inhibitor |
| Kidney benefits | Demonstrated in CKD | Demonstrated in CKD |
| Diabetes required for CKD benefit? | No, in appropriate CKD patients | No, in appropriate CKD patients |
| Main kidney effect | Promotes natriuresis and changes glomerular filtration | Similar |
| Important risks | Dehydration/volume depletion, genital infections, rare ketoacidosis | Similar |
The two medicines work through the same basic pathway. It is not accurate to assume that one is universally better for every person with CKD. The appropriate choice depends on the individual’s medical situation and approved indications.
What did the major CKD trials show?
The evidence is substantial.
In DAPA-CKD, dapagliflozin reduced the risk of a composite outcome involving substantial kidney-function decline, kidney failure, or kidney/cardiovascular death compared with placebo. Benefits were seen in people with and without type 2 diabetes. (New England Journal of Medicine)
In EMPA-KIDNEY, more than 6,600 people with CKD were studied. Empagliflozin reduced the risk of kidney disease progression or cardiovascular death compared with placebo, again with benefits seen in participants with or without diabetes. (New England Journal of Medicine)
Longer-term follow-up of EMPA-KIDNEY has also provided evidence of continuing kidney and cardiovascular benefits after the original treatment period. (New England Journal of Medicine)
These results do not mean SGLT2 inhibitors stop CKD or restore already lost kidney function. Their purpose is to reduce the rate of future deterioration in appropriate patients.
What side effects should patients know about?
Because these medicines cause more glucose to leave through the urine, they can increase the risk of genital yeast infections and sometimes urinary or genital symptoms.
They also cause some loss of sodium and water, so volume depletion or dehydration can occur, particularly in people taking diuretics or those who become ill and cannot maintain normal fluid intake.
A rare but serious complication is diabetic ketoacidosis (DKA). It can occasionally occur even when blood glucose is not extremely high.
For this reason, clinicians may advise temporarily withholding an SGLT2 inhibitor during situations such as:
- prolonged fasting
- major surgery
- severe acute illness
KDIGO specifically recommends withholding SGLT2 inhibitors during prolonged fasting, surgery, or critical medical illness. (KDIGO)
The appropriate “sick day” plan should be discussed with the prescribing clinician rather than improvised.
Are SGLT2 inhibitors safe when eGFR is low?
Low eGFR does not automatically mean an SGLT2 inhibitor cannot be used.
Evidence and guidelines support their use in selected patients with eGFR around 20 mL/min/1.73 m² and above, depending on the clinical situation. Once appropriately started, KDIGO advises that treatment can generally be continued even if eGFR subsequently falls below 20, unless it is not tolerated or kidney replacement therapy is initiated. (KDIGO)
However, starting, continuing, or temporarily withholding the medication should be individualized, particularly during acute illness.
Does everyone with diabetes and CKD need one?
Not necessarily.
Diabetes, CKD stage, albuminuria, heart failure, blood pressure, current medications, and contraindications all matter.
SGLT2 inhibitors are also not a replacement for the rest of CKD care. Blood pressure management, appropriate renin-angiotensin system blockade when indicated, diabetes management, cardiovascular risk reduction, and appropriate lifestyle and dietary measures remain important.
What should you monitor?
Depending on your situation, your clinician may monitor:
- eGFR and creatinine
- blood pressure
- hydration or volume status
- blood glucose when relevant
- symptoms of genital infection
- symptoms suggesting ketoacidosis
- other medicines that affect fluid balance or kidney function
Do not interpret a small early eGFR change as automatic evidence that the drug is harming your kidneys. Conversely, a large or unexpected change deserves medical evaluation.
When should you contact a clinician urgently?
Seek prompt medical attention for symptoms such as:
- severe weakness or confusion
- persistent vomiting
- severe dehydration
- difficulty breathing
- severe abdominal pain
- fainting
- very low urine output
These symptoms have many possible causes, but in someone taking an SGLT2 inhibitor they can sometimes signal a serious complication requiring assessment.
What should you do if you have CKD?
If you have CKD, ask your clinician whether an SGLT2 inhibitor is appropriate based on your:
eGFR + urine albumin level + diabetes status + heart failure status + other medications + overall health.
Do not start, stop, or change the medication without medical guidance.
Bottom line
Farxiga (dapagliflozin) and Jardiance (empagliflozin) are more than blood-sugar medicines. In appropriate people with CKD, they can slow kidney-function decline and reduce important kidney and cardiovascular risks. Their benefits are not limited to people with diabetes. (New England Journal of Medicine)
They appear to protect the kidneys partly by changing how the kidney handles sodium and glucose and by reducing excessive pressure within the glomeruli. A small early eGFR decline can occur and does not automatically represent kidney injury.
The key question is not simply “Is my eGFR low enough for an SGLT2 inhibitor?” It is whether the medication’s expected kidney and cardiovascular benefits outweigh its risks in your particular CKD situation.