Sodium-glucose co-transporter-2 (SGLT2) Inhibitors (Canagliflozin, Dapaglifozin, Empagliflozin, Ertugliflozin)

This leaflet is designed for people taking an SGLT2 inhibitor, also known as a ‘flozin’ or ‘gliflozin’ for type 2 diabetes.

What does this medication do?

These drugs work to lower blood sugar by causing the kidney to remove excess sugar from the body through the urine.

They also help to lower blood pressure and aid weight loss.

How do I take this medication?

This medicine is taken once daily at the same time each day, with or without food. If you miss a tablet and remember later in the day you can still take it.

If you remember the following day, do not take two tablets together.

Who can’t take this medication?

SGLT2 inhibitors may not be suitable for certain people.

These include people who: are receiving dialysis; have type 1 diabetes; are pregnant or breastfeeding; have problematic urine infections; have had ketoacidosis in the past; take drugs which suppress the immune system; have a kidney or other organ transplant; or have Chronic Kidney Disease due to polycystic kidneys, lupus nephritis, or ANCA vasculitis.

Your prescriber will review your past medical history, kidney function and other medication when prescribing a ‘flozin’ to check it is suitable for you.

What are the common side effects?

Many people will not experience side effects with these drugs. However, like all medicines, ‘flozins’ can cause side effects.

Some common side effects include:

  • Dehydration: You may find you make more urine when you take these drugs. This can sometimes lead to dehydration. This is more likely for people also taking water tablets (diuretics) such as Furosemide, Bumetanide or Metolazone. It is important that you drink water if dehydrated. Speak to your doctor if you are taking water tablets whilst on an SGLT2 inhibitor.
  • Low blood sugar (hypoglycaemia):  This is more likely to happen in people with diabetes that are already taking other diabetes medications. When you start an SGLT2 inhibitor, a change in your diabetes medicines might be needed. Your prescriber will review your other medication when prescribing a ‘flozin’ and advise you if any changes are needed.
  • Urine and fungal infections: You may get urine and fungal infections. This includes thrush around the vagina or penis. These should be reported to your doctor, pharmacist or nurse and are usually treatable. Maintaining good hygiene of the genital area should reduce your risk.

    Far less common, but important side effects of SGLT2 inhibitors include:
  • Ketoacidosis:  Acids called ketones can build up in the bloodstream. You may feel sick, dehydrated, confused, drowsy, dizzy, breathless and your breath may smell like nail varnish remover. Ketoacidosis risk is increased if you go for long periods without eating, become dehydrated, or drink excess alcohol. Very low carbohydrate diets should be avoided. You should seek urgent medical attention if you have any of these symptoms or think you may have developed ketoacidosis.
  • Foot disease: There may be a small theoretical risk of worsening foot ulcers, gangrene or severe foot infections or toe amputations, particularly among people with diabetes or who have or have had foot disease. People with diabetes should continue regular preventative foot care including podiatry appointments and seek medical attention if they develop foot ulcers.
  • Fournier’s gangrene: This is a severe deep skin infection that often causes pain, swelling and/or redness around the genital area.  If you develop such symptoms whilst taking these drugs, you should seek urgent medical attention
  • If you suspect these important side effects are present, immediately stop the SGLT2 inhibitor and seek urgent medical attention.

Do I need to be monitored?

Specific monitoring after starting an SGLT2 inhibitors is not required. Unless you feel unwell, there is usually no need to have extra blood tests after starting an SGLT2 inhibitor.

You do not need to test your own blood sugars when taking an SGLT2 inhibitor unless you are also taking other diabetes medications. Your healthcare team can advise you on this.

Your medical team will continue to monitor your kidney function as part of your routine care.  

Are there any sick day rules?

GLT2 inhibitors should usually be temporarily stopped if you are more unwell than usual, including:
• Dehydration, for example through diarrhoea, vomiting, or a high temperature
• Low blood pressure, particularly if you feel dizzy or lethargic
• During admission to hospital when unwell
• Before an operation
• If you suspect ketoacidosis or Fournier’s gangrene
• If you have a urine infection or severe thrush
• If you start dialysis or undergo a kidney transplant
• If you develop active foot disease

Diuretics, (sometimes referred to as “water tablets”) and some blood pressure medications are also usually temporarily stopped if you are dehydrated or have low blood pressure.

If you usually check your blood sugar at home, it is advised you increase the number of times you check your blood sugar when unwell.

Most people can restart SGLT2 inhibitors 48 hours after a short-term illness, especially if eating and drinking fluids normally again. But you should ask your doctor, pharmacist or nurse if you are unsure, or if you think the SGLT2 inhibitor made you unwell. There are no concerns or risks associated with temporarily not taking your SGLT2 inhibitor when unwell.

What about driving?

Certain people with diabetes need to inform the Driver and Vehicle Licensing Agency (DVLA). This depends on your medication regimen, whether you hold a group 1 or group 2 licence and other individualised factors.

Full advice can be found via the DVLA website or

If you have any queries about this medication, contact your diabetes team, GP or pharmacist.