I was recently diagnosed with diabetes and have started taking Glucophage XR, but my levels go up and down. Most days I can keep it under control if I watch my diet closely. I have managed to lose about 12 pounds and still need to lose about 15 or 20 more. My doctor tried me on Prandin, but I had a drastic drop in blood sugar about four hours after taking this medication, and my doctor said it should lower your sugar within an hour or two. I stopped taking this medication.

I had a kidney removed 20 years ago because it was never functioning properly, and I am really worried about the effects that diabetes will have on my remaining one. Is there is any research on the effects of diabetes medications and only having one kidney?

Interesting question. I would suggest that with one kidney, the creatinine would be pretty close to being at the upper limits for safe use of Glucophage XR [metformin]. Second, we know from clinical use of sulfonylurea with metformin that the hypoglycemia is more likely to respond to lowering of the sulfonylureas. Therefore, the potentiation of the Prandin with the metformin is the reason for the lows after the meals, even though it is later than the traditional action curve for Prandin. Finally, it is known that one kidney increases the blood flow in the remaining kidney and leaves it vulnerable to hyperfiltration and complications from diabetes.

JTL
Additional comments from Dr. Donough O’Brien:Prandin (repaglinide) is reported to be safe for diabetics with impaired renal function provided the initial dose is increased with caution. See Marbury TC, Ruckle JL, Hatorp V, Andersen MP, Nielsen KK, Huang WC, Strange P. Pharmacokinetics of repaglinide in subjects with renal impairment.Clin Pharmacol Ther 2000 Jan;67(1):7-15.

DOB
Additional comments from Dr. Stuart Brink:

You only need 25% of your kidney function so you have 50% of your original total kidney function assuming that the remaining kidney is normal. Any high glucose levels will cause vascular damage related to high glucose levels over many years. So, it is more important if one has only a single kidney to control glycemia than if one has two kidneys.

You should have periodic kidney function assessments with tests like 24 hour or overnight microalbumin, BUN and creatinine levels, and blood pressure determinations. In addition, you should try as much as possible to stay away from medications which include side effects related to the kidneys. Go back and talk to your diabetes team about these specifics.

SB