Metformin vs. Farxiga
See how Metformin and Farxiga compare on approved uses, dosing, side effects, and cost.
Key Takeaways
Metformin is a first-line oral biguanide that lowers blood sugar and has decades of safety data, while Farxiga is an SGLT2 inhibitor also approved for heart failure and chronic kidney disease.
Metformin mainly causes GI side effects like diarrhea and nausea, while Farxiga's main risks are genital yeast infections and urinary tract infections.
Doctors often prescribe them together, since metformin and Farxiga work through different mechanisms and can be combined for added blood sugar control.
Metformin vs. Farxiga Drug Summary
Metformin
Metformin is a biguanide that lowers blood sugar mainly by reducing glucose production in the liver and improving insulin sensitivity. It's approved for type 2 diabetes in adults and children 10 and older, and comes as an immediate-release tablet, extended-release tablet, or oral solution taken with meals.
Farxiga
Farxiga is an SGLT2 inhibitor that lowers blood sugar by causing the kidneys to remove excess glucose through urine. Beyond type 2 diabetes, it's approved to reduce heart failure hospitalizations and slow chronic kidney disease progression, and it's taken as a single tablet once a day.
Metformin vs. Farxiga Side Effects
Metformin
Farxiga
Metformin vs. Farxiga Dosage
Metformin
Farxiga
| STAGE | DOSE | WHEN |
| Starting dose | 500 mg twice daily | Week 1 |
| Maximum dose | 500 mg once daily | Week 1 |
| Dose changes | 2 increases | As tolerated |
| STAGE | DOSE | WHEN |
| Starting dose | 5 mg once daily | At the start |
| Maximum dose | 10 mg once daily | If needed |
| Dose changes | 1 increase | As tolerated |
Metformin
| STAGE | DOSE | WHEN |
| Starting dose | 500 mg twice daily | Week 1 |
| Maximum dose | 500 mg once daily | Week 1 |
| Dose changes | 2 increases | As tolerated |
Farxiga
| STAGE | DOSE | WHEN |
| Starting dose | 5 mg once daily | At the start |
| Maximum dose | 10 mg once daily | If needed |
| Dose changes | 1 increase | As tolerated |
Metformin vs. Farxiga Indications
Metformin
Metformin is FDA-approved to control blood sugar in adults and children 10 and older with type 2 diabetes. It's also used off-label for polycystic ovary syndrome and for prediabetes or weight management, though it's not approved for type 1 diabetes or diabetes prevention.
Type 2 diabetes in adults and children 10+
Off-label: polycystic ovary syndrome (PCOS)
Off-label: prediabetes and weight management
Not approved for type 1 diabetes
Farxiga
Farxiga is FDA-approved to control blood sugar in people with type 2 diabetes and to reduce heart failure hospitalizations in adults with or without diabetes. It's also approved to slow kidney function decline in chronic kidney disease, but it isn't approved for type 1 diabetes or diabetic ketoacidosis.
Type 2 diabetes in adults and children 10+
Heart failure, reduced or preserved ejection fraction
Chronic kidney disease to slow decline
Not approved for type 1 diabetes
Metformin vs. Farxiga Pros and Cons
Metformin
Metformin remains the standard starting medication for type 2 diabetes because of its long safety record and low cost. Its main downsides are gastrointestinal side effects and a boxed warning for lactic acidosis in people with kidney problems.
Pros
Roughly $4 to $30 per month, far cheaper than Farxiga
Decades of real-world safety data
Low risk of hypoglycemia on its own
Available as tablets or oral solution for flexible dosing
Cons
Common GI side effects like diarrhea and nausea
Boxed warning for lactic acidosis
Contraindicated in severe kidney impairment
No proven heart failure or kidney disease benefit
Farxiga
Farxiga offers benefits beyond blood sugar control, with approvals for heart failure and chronic kidney disease. It costs substantially more than metformin and carries a distinct set of genitourinary and metabolic risks.
Pros
Approved for heart failure and chronic kidney disease
Once-daily dosing with no titration needed
Avoids the GI side effects common with metformin
May reduce cardiovascular death risk in heart failure
Cons
Roughly $400 to $785 per month, much pricier than metformin
Risk of genital yeast infections and UTIs
Can cause ketoacidosis even with near-normal glucose
Not recommended for glucose control at low kidney function
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