Why should you not take metformin for 48 hours after having a ct scan had ct scan for pain in abdomen have had 3 surgeries in the last year all dealing with my pancreas .the ct tech told me not to take my metformin for 48 hours and i would like to know wh

The : The combination of metformin and ct contrast (the dye that is injected) can be hard on the kidneys, and can cause a condition called "lactic acidosis" where the blood becomes too acidotic and can also damage the kidneys. Waiting 48 hours has been shown to be a safe time period after receiving ct contrast to resume your metformin.

Drug interaction: Metformin taken with IV dye can cause a short term decrease in renal function. Stopping it for 2 days allows the kidneys to recover from the IV dye. Generally, a blood test is performed at 48 hours to make sure kidney function is ok. Then metformin can be restarted.

The iodine dye: Can cause decrease in renal function or even renal failure. If you are taking metformin and go into renal failure, the metformin can accumulate in your system and cause problems. You don't actually have to stop the metformin, if you get a blood test for kidney function a day after the dye, and it's ok, you can just continue the metformin. The 48 hours is an arbitrary and nonsensical fda rule.