Quick facts
| Members of the class | empagliflozin, dapagliflozin, canagliflozin, ertugliflozin |
|---|---|
| Brand names in the class | JardianceFarxigaInvokanaSteglatro |
| Drug class | Sodium-glucose cotransporter-2 (SGLT2) inhibitors |
| Generally used for | Oral medicines that lower blood sugar by making the kidneys excrete glucose in urine, and that are also used to protect the heart and kidneys in selected people. |
Health Captain explains what a medicine is generally used for, how its class works, and what to discuss with your care team. We never publish dosing, and this page cannot account for your medical history, kidney or liver function, pregnancy, or the other medicines you take. This is education, not prescribing advice — follow the instructions on your label and ask your prescriber or pharmacist.
What is SGLT2 Inhibitors?
SGLT2 inhibitors block a protein in the kidney that normally reclaims glucose from urine back into the blood. Blocking it means sugar leaves the body in urine, lowering blood glucose without relying on insulin. Several of these medicines are also approved to reduce hospitalization for heart failure and to slow chronic kidney disease, including in some people without diabetes.
Key takeaways
- They lower blood sugar through the kidney rather than through insulin, so used alone they rarely cause hypoglycemia.
- Several products in this class have approvals for heart failure and chronic kidney disease that are separate from their diabetes approval.
- Genital yeast infections and urinary symptoms are the most common practical side effects, and are the reason hygiene and hydration advice comes with the prescription.
- Ketoacidosis can occur even when blood sugar readings look normal or only mildly raised — this is the warning most likely to be missed.
- This page is general education, not prescribing advice — whether this medicine is right for you, and how it is dosed, is individualized and decided by you and your prescriber.
How it generally works
Your kidneys filter a large amount of glucose out of the blood every day and then reclaim almost all of it. A transporter called SGLT2, sitting in the kidney tubule, does most of that reclaiming. These medicines block it, so a portion of the filtered glucose is simply passed out in urine instead of being returned to the bloodstream.
Because glucose pulls water with it, the same mechanism produces a mild diuretic effect and a modest drop in blood pressure and weight. That combination — less glucose, less fluid load, and changes in how the kidney handles sodium and pressure inside the filtering units — is thought to explain why these medicines reduce heart-failure hospitalizations and slow kidney decline, benefits that appear even in people who do not have diabetes.
Common side effects
Most people tolerate SGLT2 Inhibitors well, and many effects settle as the body adjusts. Tell your prescriber or pharmacist about anything that persists or bothers you.
- Genital yeast infections (itching, discharge, soreness), more often in women but seen in men too
- Urinary frequency and passing more urine, particularly early on
- Urinary tract infections
- Increased thirst
- Lightheadedness on standing, especially alongside a diuretic
- A modest drop in weight and blood pressure
Serious side effects
These are uncommon, but they are the ones to act on rather than wait out. Contact a clinician promptly if you notice any of them. If you believe you are experiencing a medical emergency, call emergency services immediately (911 in the United States).
- Nausea, vomiting, abdominal pain, deep tiredness, and rapid breathing — the pattern of diabetic ketoacidosis, which with these medicines can occur with near-normal blood glucose (euglycaemic DKA)
- Pain, tenderness, redness, or swelling in the genital or perineal area with fever or feeling very unwell — the presentation of Fournier gangrene, a rare necrotising infection that is a surgical emergency
- Burning on urination with fever, flank pain, or confusion — may reflect a kidney infection or urosepsis rather than a simple urinary tract infection
- Marked dizziness, fainting, or very low urine output — signs of volume depletion, which can injure the kidneys
Important warnings
FDA boxed warning
A boxed warning is the strongest warning the US Food and Drug Administration applies to a medicine. It does not mean nobody should take it — it means the risk below is serious enough that it must be weighed deliberately with your prescriber.
- Lower limb amputation — canagliflozin previously carried a boxed warning about amputation risk, which FDA later removed; foot care remains part of routine advice in this class.
Other warnings and precautions
- Ketoacidosis — including euglycaemic ketoacidosis, where blood glucose is normal or only slightly high. Risk rises with illness, surgery, prolonged fasting, very low carbohydrate intake, dehydration, and alcohol. These medicines are typically held before planned surgery.
- Genital mycotic infections and Fournier gangrene — necrotising fasciitis of the perineum is rare but has been reported, and requires immediate emergency care.
- Volume depletion and hypotension — particularly in older adults, people on diuretics, and people with reduced kidney function.
- Urinary tract and kidney infections — including reports of pyelonephritis and urosepsis.
- Not for type 1 diabetes — these medicines are not approved for type 1 diabetes in the United States because of the ketoacidosis risk.
Drug interactions
Interactions are one of the most common avoidable medication problems. Keep one list of everything you take — including supplements and over-the-counter products — with the Medication List Builder, and read our guide to drug interactions.
- Diuretics — the combined fluid loss can cause dehydration and low blood pressure.
- Insulin and sulfonylureas — the added glucose lowering raises hypoglycemia risk, and prescribers often adjust those medicines.
- ACE inhibitors and ARBs — the combination is common and often deliberate, but blood pressure and kidney function are watched more closely.
- NSAIDs — can reduce kidney blood flow and add to the risk of kidney injury when someone is already volume-depleted.
- Alcohol and very low carbohydrate eating patterns — both raise the risk of ketoacidosis.
- Lithium — SGLT2 inhibitors may lower lithium levels through their effect on sodium handling.
Monitoring
What a care team typically keeps an eye on while someone is taking SGLT2 Inhibitors. The exact schedule is individual.
- Kidney function (eGFR and urine albumin) before starting and periodically afterwards
- A1C every three to six months when used for diabetes
- Blood pressure and symptoms of dizziness on standing
- Volume status and electrolytes in people also taking diuretics
Storage
- Store tablets at room temperature in the original container, away from moisture.
- Keep them out of reach of children; a single tablet is not harmless to a child.
- Do not use tablets past the expiry date printed on the bottle or blister.
Questions for your doctor or pharmacist
Pharmacists are the most under-used resource in medicine, and the conversation is usually free. Build an agenda with Appointment Prep.
- Can we go through my full medication list together — prescriptions, over-the-counter products, vitamins, herbal products, and supplements — to check for interactions, duplicates, and anything I no longer need?
- Am I taking this for blood sugar, for my heart, for my kidneys, or for more than one of those?
- What symptoms of ketoacidosis should make me stop and seek care, given that my glucose reading might look normal?
- Do I need to hold this before surgery, a colonoscopy prep, or a period of fasting — and for how long?
- What should I do if I develop genital itching or discharge?
- Do any of my other blood pressure or diabetes medicines need adjusting now?
Frequently asked questions
Why would someone without diabetes take an SGLT2 inhibitor?
Because the heart and kidney benefits are not explained by glucose lowering alone. Specific products in this class are approved to reduce heart-failure hospitalization and cardiovascular death in heart failure, and to slow the progression of chronic kidney disease, in people with or without type 2 diabetes. The approval differs by product, so it is worth asking which indication applies to you.
What is euglycaemic ketoacidosis?
Ketoacidosis is a dangerous build-up of acidic ketones. Usually it comes with very high blood sugar, but SGLT2 inhibitors can produce it while glucose stays normal or only mildly raised — because sugar is leaving in the urine. That is why the symptoms matter more than the meter reading: nausea, vomiting, abdominal pain, unusual tiredness, and fast breathing need urgent assessment.
How do I lower my chances of a yeast infection on this medicine?
Because sugar is present in the urine, the genital area is a friendlier environment for yeast. Practical steps discussed by clinicians include washing and drying the area well, not sitting in damp clothing, and treating symptoms early rather than waiting. Recurrent infections are worth reporting — they are manageable, and rarely a reason to abandon the medicine outright.
Sources
- MedlinePlus — Drugs, Herbs and Supplements — Plain-language drug information from the US National Library of Medicine; search for empagliflozin, dapagliflozin, or canagliflozin.
- DailyMed — SGLT2 inhibitor labeling — The current FDA-approved prescribing information submitted by manufacturers.
- FDA — Drug Safety and Availability — Safety communications, label changes, recalls, and shortage notices.
- American Heart Association — Heart Failure — Patient information on heart failure treatment from the AHA.
- NIDDK — Diabetes — US National Institutes of Health information on diabetes medicines.
Health Captain links to primary public-health and clinical sources so you can read the original material yourself. See our sources policy.