SGLT2 inhibitors: important safety advice

Last Updated: Monday, 12 October 2026

SGLT2 inhibitors include dapagliflozin, empagliflozin, canagliflozin and ertugliflozin. They lower blood sugar by passing extra sugar into your urine. Some also treat heart failure and kidney disease.

The MHRA, the UK medicines regulator, has warned about two rare but serious side effects.

Diabetic Ketoacidosis (DKA)

DKA happens when harmful acids called ketones build up in the blood. It can happen even if your blood sugar is normal or only slightly raised.

Warning signs include:

• Feeling sick, vomiting or tummy pain.
• Fast, deep breathing.
• Unusual sleepiness or confusion.
• Sweet or fruity-smelling breath.
• Rapid weight loss.

Stop taking your SGLT2 medicine and seek medical help immediately if you develop these symptoms. You may need a blood ketone test. Do not restart it until a clinician says it is safe.

 

Fournier's gangrene: a serious infection

This is a rare, potentially life-threatening infection around the genitals or the area between your genitals and anus (back passage). It can affect both men and women.

Warning signs include severe pain, tenderness, redness or swelling in these areas, together with a high temperature or feeling generally unwell.

Seek medical help immediately if you have these symptoms. Go to A&E if you cannot get immediate help. Tell the clinician you take an SGLT2 inhibitor. If this infection is suspected, the medicine must be stopped and urgent hospital treatment started.

When to call 999

Call 999 if you have severe difficulty breathing, severe confusion or collapse. Do not wait for a routine medication review if you have warning symptoms.

If you become unwell or need surgery

Temporarily stop taking your SGLT2 medicine if you have vomiting, diarrhoea, dehydration, or an illness that stops you eating and drinking normally. Follow the sick-day advice given by your healthcare team.

Restart once you feel well and have been eating and drinking normally for 24–48 hours, unless your clinician advises otherwise. Take your usual dose; do not take extra doses to make up for those missed.

Contact your GP practice or NHS 111 if you cannot keep fluids down, remain unwell for more than 48 hours, or are unsure when to restart.

If you have symptoms of ketoacdidosis, seek medical help immediately. Do not restart your SGLT2 medication until a clinician says it is safe.

Do not stop insulin. Follow your diabetes team’s advice about adjusting your insulin when unwell.

If you are having surgery, ask your healthcare team when to stop and restart your SGLT2 medicine.

Want to discuss your medicine?

Contact your GP practice to book a medication review with a clinician, including advice on what to do when you are unwell.

Further information:

• MHRA advice about diabetic ketoacidosis
• MHRA advice about Fournier’s gangrene