Metformin and an iodinated contrast examination: which instructions should you clarify?

When booking a prescribed CT scan, tell the service that you take metformin. Also provide your other treatments and the examination prescription. French Health Insurance asks patients to report regular medicines, particularly those for diabetes, before the examination.

Ask whether the examination involves an iodine-based contrast injection into the bloodstream. The leaflet for METFORMINE BIOGARAN 1000 mg film-coated tablets cited here concerns this situation. This precaution cannot be applied to every imaging examination or every contrast product.

Ask your doctor which kidney checks are needed. The product information for this formulation explains that iodinated contrast injected into blood vessels can affect kidney function, allow metformin to accumulate and increase the risk of lactic acidosis. Kidney checks and their interpretation are medical decisions.

Ask your doctor when to interrupt and restart treatment, and whether temporary replacement treatment is needed. The leaflet assigns these decisions to the doctor; the product information also requires kidney function to be reassessed and stable before restarting. Do not decide on a pause or restart yourself from a time interval found online.

Before the appointment, follow the radiology service’s preparation instructions. Instructions about meals and medicines differ according to the scan. Bring the examination prescription, your treatment prescriptions and the requested previous results, including blood test results.

For the cited METFORMINE BIOGARAN, the leaflet describes rare but very serious lactic acidosis. Vomiting, abdominal pain, cramps, feeling generally unwell with severe tiredness, breathing difficulties, or reduced body temperature and heart rate are among its signs. If these symptoms occur, the leaflet requires stopping the medicine and contacting a doctor or the nearest hospital immediately.