SGLT2 inhibitors started as diabetes tablets, but they turned out to protect the heart and kidneys too. They are now prescribed to many people without diabetes, which is why it helps to understand how they work and what to watch for.
Imagine being prescribed dapagliflozin for heart failure. You do not have diabetes, so you wonder why you are taking a “diabetes medicine”. The answer lies in what these tablets do to the kidneys and heart.
How they work
Sodium-glucose co-transporter 2 (SGLT2) inhibitors make the kidneys pass more glucose and salt into the urine. This lowers blood sugar in people with diabetes, and also reduces fluid build-up and strain on the heart and kidneys.,Common SGLT2 inhibitors include dapagliflozin, empagliflozin and canagliflozin. Their names usually end in “-gliflozin”.
What they are used for
- Type 2 diabetes, to lower blood sugar
- Heart failure, with or without diabetes, to reduce hospital admissions and deaths
- Chronic kidney disease, to slow its progression
- Reducing cardiovascular risk in some people with type 2 diabetes
Benefits
Large clinical trials have shown that SGLT2 inhibitors reduce the risk of hospital admission for heart failure and slow the decline of kidney function in many people. They usually cause modest weight loss and a small fall in blood pressure. On their own, they rarely cause low blood sugar.
Common side effects
- Passing more urine
- Genital thrush and other genital infections, because of sugar in the urine
- Urinary tract infections
- Thirst and dehydration
- Dizziness from lower blood pressure
- A small initial dip in kidney function on blood tests, which is expected
Preventing genital infections
- Wash the genital area daily with water or a mild, unperfumed cleanser
- Dry carefully
- Wear cotton underwear
- Seek treatment early if you notice itching, redness or discharge
- Tell your healthcare provider if infections keep coming back
Diabetic ketoacidosis (DKA): a rare but serious risk
In people with diabetes, SGLT2 inhibitors can rarely cause diabetic ketoacidosis, a serious condition where acids called ketones build up in the blood. Unusually, it can occur even when blood sugar is only mildly raised, which is called euglycaemic DKA, so it can be missed.,Seek urgent medical help if you feel very unwell with nausea, vomiting, tummy pain, fast breathing, unusual tiredness or confusion, even if your blood sugar is normal. Tell the team that you take an SGLT2 inhibitor so they can check your ketones.
Sick day rules
If you are unwell with vomiting, diarrhoea or fever, or cannot eat and drink normally, your healthcare provider may advise pausing your SGLT2 inhibitor until you are eating and drinking normally again, usually for 24 to 48 hours. This reduces the risk of dehydration and DKA. Follow your personal sick day plan.
Before surgery or fasting
SGLT2 inhibitors are usually stopped a few days before major surgery or procedures that require fasting, to reduce the risk of DKA. Tell your surgical team you take one. If you fast for religious reasons, discuss a plan with your healthcare provider beforehand.
Very low-carbohydrate diets
Following a very low-carbohydrate or ketogenic diet while taking an SGLT2 inhibitor may increase the risk of ketoacidosis. Talk to your healthcare provider before making major changes to your diet.
Foot care
Canagliflozin was linked in one trial to a higher risk of lower-limb amputations, though this has not been seen consistently with other SGLT2 inhibitors. If you have diabetes, check your feet daily, report any wounds, ulcers or infections promptly and attend foot checks.
Frequently asked questions
Will I have low blood sugar?
Rarely on their own. The risk is higher if combined with insulin or sulfonylureas.
Why is there sugar in my urine test?
It is expected with these medicines and does not mean your diabetes is out of control.
Can I take it if I do not have diabetes?
Yes, for heart failure or chronic kidney disease, if your healthcare provider prescribes it.
But my kidney test got slightly worse after starting
A small dip in kidney function in the first weeks is expected and is usually followed by long-term protection. Your healthcare provider will monitor it.
Your next step: If you take an SGLT2 inhibitor, ask your healthcare provider for a written sick day plan.
Related: Kidney function tests · Heart failure care
Sources: National Institute for Health and Care Excellence, UK Medicines and Healthcare products Regulatory Agency, European Society of Cardiology heart failure guidelines, KDIGO, American Diabetes Association.
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