Farxiga Side Effects: What to Expect and When to Call Your Doctor

Farxiga (dapagliflozin) is a well-studied medication with an established safety profile across millions of patients with type 2 diabetes, heart failure, and chronic kidney disease. Like all medications, it comes with side effects — most of which are mild and manageable. But some are serious and require immediate medical attention. This guide explains what to expect, what's normal, and what's a warning sign.

How Farxiga's Mechanism Creates Its Side Effects

Farxiga works by blocking the SGLT2 protein in the kidneys, causing excess glucose and sodium to be excreted in the urine rather than reabsorbed into the bloodstream. This mechanism — urinary glucose and sodium excretion — explains most of Farxiga's side effects. More glucose in the urine creates a favorable environment for yeast and bacterial infections. More sodium excretion can affect fluid balance and blood pressure.

Common Side Effects of Farxiga (Usually Mild)

These side effects occur in at least 2% of patients in clinical trials and are generally manageable:

Female genital mycotic infections (vaginal yeast infections): The most common side effect in women, occurring in up to 6-8% of female patients. Caused by elevated glucose in the genital area from urinary excretion. Usually treatable with over-the-counter antifungals. Maintaining good genital hygiene reduces risk.

Urinary tract infections (UTIs): Increased urinary glucose can promote bacterial growth. Most UTIs respond well to standard antibiotics. If you have recurrent UTIs, discuss with your doctor whether Farxiga is appropriate for you.

Nasopharyngitis (upper respiratory symptoms): Reported in clinical trials but may reflect background rates of common colds rather than a drug-specific effect.

Increased urination: Farxiga causes osmotic diuresis — more urination — especially early in treatment. This typically decreases over time. Stay well hydrated.

Back pain: Reported in clinical trials at slightly higher rates than placebo.

Modest weight loss: Patients taking Farxiga lose an average of ~6 pounds over 24 weeks due to caloric loss via urinary glucose excretion. This is generally a benefit for most patients with T2DM.

Serious Side Effects That Require Immediate Medical Attention

The following side effects are rare but serious. Stop taking Farxiga and seek emergency care if you experience any of these:

Diabetic Ketoacidosis (DKA): A life-threatening emergency. Symptoms include nausea, vomiting, abdominal pain, extreme fatigue, trouble breathing, and fruity-smelling breath. Can occur in patients with type 1 OR type 2 diabetes. Note that Farxiga-induced DKA can occur even at relatively normal blood sugar levels (euglycemic DKA). If you have these symptoms, stop Farxiga and seek emergency care immediately.

Severe dehydration and low blood pressure: Symptoms include dizziness, lightheadedness when standing, rapid heartbeat, feeling very thirsty, or decreased urination. Most likely in elderly patients or those on diuretics.

Urosepsis or pyelonephritis: A urinary tract infection that has spread to the kidneys or bloodstream. Symptoms include high fever, shaking/chills, extreme fatigue, flank pain (pain in your back or side). This is a medical emergency — go to the ER.

Necrotizing fasciitis of the perineum (Fournier's Gangrene): Extremely rare but life-threatening. A severe infection affecting the skin and tissue around the genitals and anus. Symptoms include pain, redness, swelling, or tenderness in the groin or perineal area, often with fever. Requires emergency surgery. Seek care immediately if you have these symptoms.

Hypoglycemia (low blood sugar): Farxiga alone rarely causes hypoglycemia, but the risk increases significantly when combined with insulin or sulfonylureas (e.g., glipizide, glyburide). Symptoms: shakiness, sweating, dizziness, confusion, rapid heartbeat. Treat with 15g of fast-acting carbohydrates.

Allergic reactions: Severe allergic reactions including anaphylaxis and angioedema have been reported. Symptoms: skin rash, hives, swelling of the face, lips, tongue, or throat, difficulty breathing. Stop Farxiga and seek emergency care immediately.

Acute kidney injury: Volume depletion from Farxiga can contribute to acute kidney injury. Symptoms: decreased urination, swelling in legs/ankles, fatigue, confusion. Contact your doctor right away.

When to Call Your Doctor vs. When to Go to the ER

Call your doctor (non-emergency) if you experience:

Vaginal yeast infection or mild UTI symptoms

Persistent excessive urination or thirst beyond the first few weeks

Mild dizziness or lightheadedness when standing

Back pain that doesn't resolve

Go to the emergency room immediately if you experience:

Nausea, vomiting, abdominal pain, difficulty breathing, or fruity breath (possible DKA)

Fever, chills, back/flank pain with UTI symptoms (possible urosepsis)

Severe groin or perineal pain, redness, or swelling (possible Fournier's gangrene)

Anaphylaxis symptoms — swollen throat, trouble breathing, severe hives

Important: Stop Farxiga Before Surgery

Hold Farxiga for at least 3 days before any planned surgery or procedure that involves prolonged fasting. This reduces the risk of perioperative diabetic ketoacidosis. Always tell your surgical team you are taking Farxiga. Resume only when you have restarted oral intake and your doctor clears you.

For information on drug interactions that can increase Farxiga's side effect risk, read our guide on Farxiga drug interactions. If you're having trouble filling your Farxiga prescription, visit medfinder.com for help locating it at a pharmacy near you.