What are SGLT-2 Inhibitors?

SGLT-2 inhibitors, also known as ‘flozins’, are tablets that were originally developed as a treatment for diabetes, but have now been found to also help your heart and your kidneys.

SGLT-2 inhibitors have been shown to be very safe for kidney patients and actually protect the kidneys, slowing the decline of your renal function. They do this by helping to remove excess sugar and salt from the body, via your urine. In doing this, it also helps to reduce high blood pressure within the kidney to protect it from long-term damage. Examples of SGLT-2 inhibitors include canagliflozin, dapagliflozin and empagliflozin. 

Who should take SGLT-2 inhibitors?

SGLT-2 inhibitors are recommended for adult patients with chronic kidney disease to help slow the decline of your kidney function.

Before starting an SGLT-2 inhibitor, your doctor should make sure that you are already on the highest tolerated dose of an angiotensin-converting enzyme (ACE) inhibitor or angiotensin-receptor blocker (ARB) (unless you are allergic or unable to take one of these medications).

SGLT-2 inhibitors can be used for patients with chronic kidney disease stages 2, 3a, 3b and 4 (eGFR 20-90 ml/min/1.73m²). The amount of protein in your urine and whether or not you have type 2 diabetes will determine whether an SGLT-2 inhibitor is suitable for you – Your doctor will be able to tell you if you might benefit from starting treatment. 

How do I take this medicine?

SGLT-2 inhibitors are to be taken once a day, at the same time each day. You can take the tablet with or without food.

If you forget to take your tablet and remember later the same day, you can take it when you remember – if you do not remember until the next day, do not take an extra tablet to make up for the missed dose, just take your next dose at the usual time. 

Are there any side-effects?

Many people will not experience any side effects while taking an SGLT-2 inhibitor, but it is important to be aware of the common and more significant side effects and what to do if you experience them.

Common:

-     Dehydration – this may occur because SGLT-2 inhibitors increase the volume of urine your body produces. To avoid dehydration, you should make sure that you are drinking enough water to maintain pale, clear urine and increase water intake if you feel dehydrated.

-        Low blood sugar levels – this is usually only experienced by patients who have diabetes and are on other blood glucose lowering drugs. If you have diabetes, ensure your GP and/or diabetes team are informed when you start this medication.

-        Fungal genital infections – SGLT-2 inhibitors increase the concentration of glucose in the urine, which can increase the risk of thrush in the genital area. This is easily treatable, and your pharmacist or GP can give you advice if you experience irritation or itching in your genital area. Maintaining good hygiene and avoiding tight underwear and perfumed soaps will reduce the risk of infections. 

Rare side effects which are important to know about for all patients:

-          Fournier’s gangrene – this is an extremely rare but serious infection of the genitalia or the area between the genitals and the anus. You should stop taking your SGLT-2 inhibitor and seek urgent medical attention if you have a fever or feel unwell along with severe pain, tenderness or swelling in these areas. 

Rare side effects which are important to know about for patients with diabetes:

-          Diabetic ketoacidosis – this is where there is a build-up of an acid called ketones in the blood, which can cause you to feel sick, drowsy, dizzy and confused. It can also cause your breath to smell like pear drops. The risk is increased if you do not eat or drink for prolonged periods of time, and if you drink too much alcohol. This can happen even if your blood glucose levels are normal. If you think you have any of these symptoms or think you have developed ketoacidosis, seek urgent medical attention. 

What if I become unwell while taking an SGLT-2 inhibitor?

It is important that you temporarily stop taking your SGLT-2 inhibitor if you become unwell with symptoms such as fever, vomiting and dehydration, or if you are fasting (e.g. before an operation).  By temporarily stopping, you will reduce your risk of becoming more dehydrated and unwell. If you are in any doubt, speak to your GP, pharmacist or nurse for advice, or call NHS 111. Once you have been eating and drinking normally again for 24-48 hours, you can continue taking your SGLT-2 inhibitor as usual.  If you have planned restriction of food intake (e.g. Ramadan), speak to a healthcare professional for advice.

Written by
Matt Holloway: Renal Pharmacist – East Kent Hospitals University NHS Foundation Trust
Hollie Curtis: Renal Pharmacist – East Kent Hospitals University NHS Foundation Trust

Written February 2024
Next review February 2027

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The National Kidney Federation cannot accept responsibility for the information provided.  The above is for guidance only.  Patients are advised to seek further information from their own doctor.