Some medicines and herbal supplements affect how metformin works.
If you’re taking any other medicines or supplements, check with a GP or pharmacist before you start taking metformin.
Medicines that can affect metformin
Your GP may tell you to check your blood glucose levels more often or they may change your dose if you are taking:
- steroid tablets, such as prednisolone
- tablets that make you pee more (diuretics), such as furosemide
- medicines to treat heart problems and high blood pressure (hypertension)
- male and female hormones, such as testosterone, oestrogen or progesterone
- other diabetes medicines
The pill and metformin
Your GP may adjust the dose of metformin if you start taking a contraceptive pill.
This is because the pill can change how your body handles sugar.
X-ray, scans and surgery
Tell your GP if you are having:
- an x-ray or scan that uses an injection of contrast dye - rarely metformin and contrast dye together can affect your kidneys
- surgery