Farxiga and Metformin: Do You Need Both?

If you live with Type 2 diabetes, you’re likely familiar with the terms blood glucose (sugar) and hemoglobin A1C (HbA1C or A1C). And you and your healthcare provider have probably discussed ideal goals for you to meet. In addition to a diabetes-friendly diet and regular exercise, medications are often an essential part of managing this condition.

Metformin is the most commonly prescribed oral medication for Type 2 diabetes. It’s often taken on its own. But sometimes, it’s combined with a second medication to help people meet their diabetes treatment goals. One potential option is taking metformin with Farxiga (dapagliflozin), another oral diabetes medication.

How do Farxiga and metformin work?

Farxiga and metformin both help lower blood glucose and A1C levels (your average glucose over the past 3 months). But each medication does this differently. 

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Metformin belongs to the biguanide medication class and it works in several ways. It causes your gut to absorb less glucose from your diet, while also causing your liver to make less glucose. What’s more, metformin makes your body’s natural insulin work better, so more glucose from your blood moves into your cells.

Farxiga is a sodium-glucose cotransporter 2 (SGLT2) inhibitor. Its name sounds complicated, but how it lowers glucose is simple. It causes your kidneys to remove more glucose from your blood, and this excess glucose leaves your body when you pee.

Farxiga clears extra sodium from the blood, too. And that’s often a good thing because too much sodium can contribute to other health problems. Experts think this is one of the reasons why Farxiga has added heart and kidney protective benefits for some people.

Can Farxiga and metformin be taken together?

Yes. In fact, the FDA evaluated this combination before approving Xigduo XR (dapagliflozin / metformin). Xigduo XR contains the active ingredients of Farxiga and metformin in a single pill. It’s one example of a combination diabetes medication.

Xigduo XR can help cut down on the number of pills you take per day. But your healthcare provider can also prescribe each medication separately. This allows for more flexibility in the specific doses used.

Why are Farxiga and metformin sometimes prescribed together?

Metformin is a first-choice medication for Type 2 diabetes. For many people, it works well by itself. But sometimes, another medication is needed, too. Farxiga is one option that might be prescribed for you with metformin. Your provider might prescribe it for you when you first start taking metformin or later on as an add-on medication.

The American Diabetes Association (ADA) guidelines recommend taking metformin and a medication like Farxiga together in several situations. Below are some reasons why your healthcare provider might recommend this combination for you.

Heart protection

If you have Type 2 diabetes and heart disease, taking Farxiga along with metformin can be beneficial. Your provider may also recommend it if you don’t have heart disease, but your risk of heart disease is high.

That’s because people with Type 2 diabetes have a 2 to 3 times higher risk for heart disease. So it’s common for someone to have both conditions. And, multiple studies show that medications like Farxiga can help lower the risk for heart failure-related hospitalizations, and even death related to heart disease.

In fact, the FDA has approved Farxiga to treat certain types of heart failure — even in people without diabetes.

Kidney protection

If you have CKD, your healthcare provider might prescribe both Farxiga and metformin. That’s because up to 40% of people with diabetes also have chronic kidney disease (CKD). And, both CKD and Type 2 diabetes are risk factors for heart disease.

So, combining Farxiga with metformin can help protect kidney function and prevent hospitalizations from heart failure or death related to heart disease — in people with Type 2 diabetes.

Much like with heart failure, the FDA has approved Farxiga to treat CKD in people with or without diabetes. Farxiga can prevent, or slow, the worsening of CKD. But it’s not recommended to start Farxiga if your eGFR (an estimation of kidney function) is less than 25 mL/min.

Better blood glucose control

Depending on your initial A1C level, your healthcare provider may initially recommend a combination of oral medications. Or they may recommend adding on a second medication later, if your A1C starts creeping up after you’ve been taking metformin for a while.

On average, adding a second diabetes medication can lower A1C by 0.7% to 1.0%. But note, Farxiga is not the preferred add-on medication for this reason alone. So, if you don’t have heart disease or CKD, but you are struggling to meet your diabetes treatment goals, there are other diabetes medications your healthcare provider might consider first, such as a sulfonylurea, Mounjaro (tirzepatide), or other injectable diabetes medications.

Can you lose weight on Farxiga and metformin?

It’s possible. But neither medication is approved for weight loss.

According to the ADA’s latest guidelines, metformin provides little or no weight loss for most people. Other studies have noted up to a 6-pound weight loss for some people after they took metformin for a year.

Adding Farxiga to metformin can result in more weight loss than taking metformin alone. In one study, about one-third of people who added Farxiga to metformin lost more than 5% of their starting body weight after one year.

However, another group of diabetes medications — glucagon-like peptide-1 (GLP-1) agonists — are the most likely to help with weight loss. Ozempic (semaglutide) is one example.

How are Farxiga and metformin taken?

If you’re prescribed Xigduo XR — the combined Farxiga-metformin product — you’ll take it once daily. Your dose should be taken with food at the same time each morning.

If you’re taking Farxiga and metformin separately, follow the directions for each. Farxiga is taken once daily with or without food. Taking your dose in the morning is usually recommended. This is because Farxiga can make you pee more often. You’ll be less likely to have your sleep interrupted if you take your dose earlier in the day.

Metformin comes in two oral tablet forms, each with unique dosages:

• Immediate release (IR): Metformin IR is typically taken 1 to 3 times daily with meals. If you take it once daily, take your dose with the same meal each day. If you’re taking it 2 or 3 times daily, doses should be evenly spaced and taken with meals.

• Extended release (ER): Metformin ER is usually taken once daily with your evening meal.

Are there risks in taking Farxiga and metformin together?

For many people, Farxiga and metformin are safe to take together. In this case, the benefits of taking these medications outweigh the potential risks.

However, it’s important to know that certain risks may be higher when you combine Farxiga with metformin. For example, all diabetes medications can increase the risk of hypoglycemia (low blood glucose) — especially in people who also take insulin. And, the risk goes up the more diabetes medications you take.

Farxiga and metformin also have their own respective side effects and interactions that raise the risk of certain side effects. Below, we discuss some of these risks. But it’s not a comprehensive list of either medication’s side effects or interactions.

You should discuss the risks of each medication with your healthcare provider before starting them. Make sure to share an up-to-date list of your current medications so they can check for interactions.

Farxiga side effects

Farxiga can affect fluids in your body, resulting in side effects. Some of these are expected, such as peeing more frequently. But others can be more serious, like dehydration. Taking Farxiga with diuretics (“water pills”) can make dehydration more likely to happen.

Farxiga can also raise your risk for certain infections, including genital yeast infections for both men and women as well as urinary tract infections.

Metformin side effects

During the first 2 weeks of taking metformin, more than half of people have stomach-related side effects. These include diarrhea, gas, and nausea. The good news is these digestive issues usually get better as your body adjusts to metformin.

Lactic acidosis is a rare but serious side effect that causes symptoms like confusion, a fast heartbeat, and rapid breathing. Certain medications, such as topiramate (Topamax), can raise the risk of lactic acidosis when taken with metformin. Drinking alcohol while taking metformin can also raise the risk.

How to save on Farxiga and metformin

Farxiga and certain forms of metformin are available as brand-name medications. But you can also find metformin as a lower-cost generic. GoodRx can help you navigate the many ways to save on your prescription.

• Save with GoodRx. GoodRx can help you save over 89% off the average retail price of the generic version of metformin IR. Generic metformin’s price at certain pharmacies is as low as $6.99 with a free GoodRx discount.

• Save with a copay savings card. If you have commercial insurance, you may be eligible to pay as little as $0 per month for Farxiga using a savings card from the manufacturer.

• Save with patient assistance programs. If you’re uninsured or underinsured, you may be eligible for Farxiga’s patient assistance program, which offers the medication free of cost.

Why trust our experts?

Written by:

Daphne Berryhill, RPh

Daphne Berryhill, RPh, has two decades of experience as a clinical pharmacist. She spent most of her career in the Chicago area practicing in-home infusion.

Reviewed by:

Alyssa Billingsley, PharmD

Alyssa Billingsley, PharmD, is the director of pharmacy content for GoodRx. She has over a decade of experience as a pharmacist and has worked in clinical, academic, and administrative roles.

Reviewed by:

Farah Naz Khan, MD

Farah Naz Khan, MD, is a board-certified physician at the UW Medicine Diabetes Institute and a clinical assistant professor of metabolism, endocrinology, and nutrition at the University of Washington.

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