I am having cataract surgery a week from Monday. I had to get clearance from my GP for it, so went to him two day ago. He told me I need to stop taking Metformin 48 hours before my surgery. I am already aware of this warning about Met, that it needs to be stopped before surgery or before any procedure involving contrast dye. I know that the reason this is the standard recommendation is because there is an increased risk of lactic acidosis on Met if the kidneys are compromised. What I don't understand is how my kidneys would be compromised during cataract surgery because it does not involve general anesthesia? Does anyone have any thoughts or experience with this? For those unfamiliar with this "warning", here is an explanation:
X-ray dye Metformin should be stopped at the time of, or just prior to a procedure using X- ray dye containing iodine. The kidneys clear X-ray dye and rare cases of diminished kidney function have occurred because of the dye. Since the kidney clears metformin, it could cause a build-up of metformin and potentially increase the risk of lactic acidosis. The procedures that use iodinated dye include the hysterosalpingogram (HSG) in evaluation of infertility, intravenous pyleogram (VIP) often to exclude a kidney stone or evaluate the urinary tract for recurrent infection and abnormalities, evaluation for gall bladder disease (cholangiogram), and tests to evaluate for blood clots, coronary artery function (angiogram), and CT / MRI scans. Metformin can be safely started in 48 hours if there have been no problems with the procedures.
Surgery The same rationale for withholding metformin before procedures using X-ray dye can be said for surgery. Metformin should be discontinued until a regular diet and fluid intake has resumed.
I plan to call my ophthamologist's office and ask about this. The thing is, I had forgotten to ask my GP about stopping the Met while I was there, so I called and left a message yesterday and got a call back from the nurse who left me the message to stop the Met 48 hours prior. So I haven't had a chance to question my doc further about this. I have a feeling he will still give me the pat answer, but I really want to know the reasoning behind it if no general anesthesia is used (I can drink water the morning of the surgery so I am not in danger of dehydration, btw).
Side note: I got my doc to prescribe Gluc XR and I started it on Thurs. night (have been on regular Met for over two years). I have already seen a great reduction in my morning blood sugars, so I am very pleased. I guess this is what my body needed to get over the "dawn phenomenon" thing.
Thanks for any input anyone can give me.