Farxiga for heart failure: How it works, effectiveness & more

Heart failure is a long-term condition that can affect one or both sides of the heart and occurs when the heart cannot pump enough blood. Symptoms of this serious health condition include shortness of breath, fatigue, coughing, swelling, weight gain, and frequent urination, among others. Heart failure causes fluid buildup as well as decreased blood flow to the organs. This can lead to other serious conditions such as breathing difficulties, kidney or liver problems, pulmonary hypertension (high blood pressure in the lungs), other heart problems, and malnutrition. Farxiga is one of the treatment options for heart failure. 

Farxiga is an oral prescription drug containing the active ingredient dapagliflozin and made by the pharmaceutical company AstraZeneca. It is classified as a sodium-glucose cotransporter 2 (SGLT2) inhibitor. Farxiga was approved by the Food & Drug Administration (FDA) in 2014 for the following indications:

• In adult patients with heart failure: To lower the risk of cardiovascular (CV) death, hospitalization for heart failure, and urgent heart failure visits
• In adults with chronic kidney disease at risk for progressing: To lower the risk of CV death, kidney disease progression, end-stage kidney disease, heart failure hospitalization, and urgent heart failure visits—those that involve a trip to the ER but do not meet the criteria for hospitalization
• In adults with Type 2 diabetes who also have cardiovascular disease (heart disease) or multiple risk factors: To lower the risk of hospitalization for heart failure
• In adults with Type 2 diabetes mellitus: To improve blood sugar control, also known as glycemic control (along with diet and exercise)

This article focuses on the use of Farxiga for heart failure. 

The role of Farxiga and benefits for heart failure

As an SGLT2 inhibitor, Farxiga works by blocking glucose (sugar) from reabsorbing in the kidneys and helping the kidneys eliminate glucose through the urine. This helps lower blood sugar. Farxiga also reduces sodium reabsorption in the kidneys. Blocking sugar and sodium reabsorption also helps the heart pump blood through the body, which can benefit people with heart failure.  

The initial FDA approval of Farxiga for heart failure was for people with heart failure with a reduced ejection fraction. The indication was based on a clinical trial published in 2019 in the New England Journal of Medicine (NEJM). It studied over 4,700 patients with mild, moderate, or severe heart failure and a left ventricular ejection fraction of 40% or less. Ejection fraction is a measure of the blood the heart pumps out, and an ejection fraction of 40% or less means that the heart muscle is weakened, indicating heart failure or a risk of heart failure. Ejection fraction measurements can be taken on either the left or right ventricle. 

• Left ventricular ejection fraction (LVEF) measures how much oxygen-rich blood is pumped out of the left ventricle to the body’s organs with each contraction. This measure helps determine the severity of dysfunction on the left side of the heart.
• Right ventricular ejection fraction (RVEF) measures the amount of oxygen-poor blood pumped out of the right side of the heart to the lungs. This condition is less common than left-sided heart failure.

In the NEJM study, patients took either Farxiga 10 mg daily or a placebo (inactive medicine) in addition to the recommended therapy. The study found that patients who took Farxiga had a lower risk of worsening heart failure, as well as a lower risk of death from heart-related causes, than those in the placebo group. 

In 2022, another trial was published in NEJM. This time, the researchers studied over 6,200 patients with heart failure and LVEF of more than 40%. Patients took either Farxiga 10 mg daily or a placebo in addition to usual therapy. The study found that, in patients with heart failure and a mildly reduced or preserved ejection fraction, Farxiga reduced the risk of worsening heart failure and risk of death from heart-related causes.

With these results, the FDA expanded the indication for Farxiga to reduce the risk of heart-related death, heart failure hospitalization, and urgent heart failure visits in adults with heart failure (not just for adults with heart failure with reduced ejection fraction). This new approval meant that more people with heart failure could take Farxiga regardless of LVEF status.

Farxiga dosages for heart failure

Before taking Farxiga, your healthcare provider will check your kidney function and volume status. If you are volume-depleted (have low fluid volume), your healthcare provider will need to correct the condition before you start taking Farxiga.

The dosage of Farxiga is based on the estimated glomerular filtration rate (eGFR), a measure of kidney function. Farxiga is available in 5 milligram (mg) and 10 mg tablets.

For heart failure, the dosage for individuals with an eGFR of 25 or greater is 10 mg by mouth once daily. If the eGFR is less than 25, healthcare providers will not start treatment with Farxiga. However, if you are already taking Farxiga, your provider may recommend continuing to take it. 

While taking Farxiga, if you are having any type of surgery, notify your healthcare provider. The prescribing information states that, if possible, you should not take Farxiga for at least three days before major surgery or procedures associated with fasting.

Farxiga side effects & warnings

Common Farxiga side effects include:

• Frequent urination, including during the night
• Stuffy nose
• Runny nose
• Sore throat
• Leg pain
• Arm pain
• Constipation 

Serious side effects of Farxiga may include:

• Urinary problems including frequent, burning, urgent, or painful urination; or decreased urine; strong-smelling urine; discolored urine
• Fever, nausea, vomiting, back pain
• Dehydration: dry mouth and skin, dark urine
• Pelvic or rectal pain
• In females: vaginal itching, odor, or discharge
• In males: penis redness, rash, itching, swelling, pain, or foul-smelling discharge
• Fatigue, weakness, fever, along with pain, redness, swelling, and tenderness of the genitals or the area between the genitals and rectum  

If you have symptoms of an allergic reaction, stop taking Farxiga and get emergency medical help. Symptoms may include rash, hives, difficulty breathing or swallowing, or swelling of the face, lips, tongue, or throat. 

Symptoms of diabetic ketoacidosis require emergency medical help. Symptoms may include nausea, vomiting, stomach pain, fatigue, and difficulty breathing. 

Farxiga can also cause dehydration. Ask your healthcare provider how much fluid you should drink while taking Farxiga. You should avoid alcohol while taking Farxiga. 

Tell your healthcare provider about all the medications you take, including prescription and over-the-counter drugs, vitamins, and supplements. People who use insulin or take certain diabetes medicines will need close blood sugar monitoring as well as a possible dosage change. Your healthcare provider will advise you on this. 

Who should not take Farxiga for heart failure?

Before taking Farxiga, let your healthcare provider know about all of your medical conditions and medical history. 

You should not take Farxiga if you are allergic to dapagliflozin or any ingredient in the medication.

Farxiga should not be used in the second or third trimester of pregnancy. If you are in the first trimester of pregnancy or trying to become pregnant, consult your healthcare provider. You should not take Farxiga while breastfeeding.

If you have a certain degree of kidney problems, your healthcare professional may decide against starting this medication. 

How much does Farxiga cost?

According to the manufacturer’s website, people with commercial health insurance pay an average out-of-pocket cost of about $25 per month, although costs vary by plan. You can contact your health insurance plan to verify your cost. People with commercial insurance may be able to pay $0 for Farxiga with the Farxiga Savings Card Program. Contact the manufacturer for more information and eligibility requirements. 

The average out-of-pocket cost for individuals with Medicare Part D prescription coverage is about $39 per month. For those with Medicaid, out-of-pocket costs vary by state. Contact your plan for more information.

If you do not have insurance or your insurance does not cover Farxiga, you can use a SingleCare discount. Without insurance, a one-month supply of 30, 10 mg tablets of Farxiga costs about $797. Using a free Farxiga SingleCare coupon can lower the price to as low as $558. 

People who are uninsured, or those with Medicare Part D and high out-of-pocket costs, can also inquire about the Farxiga patient assistance program called AZ&Me, which helps eligible patients get AstraZeneca medications at no cost.

You can also call 855-3FARXIGA to speak to a Farxiga Savings Specialist for more information about saving on Farxiga.

If you have explored all options, and the price is still too high, you can ask your healthcare provider about possible Farxiga alternatives that may be more affordable.