From the January 2005 Issue

In our August 2004 article, Oral Antidiabetic therapy:Not as easy as it used to be, we recommended that prescribers perform a baseline and periodic re-evaluation of renal function for patients receiving any metformin-containing medication, and that this information should be shared with pharmacists upon request.

One reader contacted us about changes he programmed into his pharmacy computer system to alert staff to verify serum creatinine and calculate the estimated creatinine clearance for patients over the age of 65 who were receiving any formulation of metformin. In a single month, staff recommendations led to the discontinuation of metformin in two patients based on serum creatinine levels above 1.5 mg/dL. There were also dosage adjustments in several other patients. Pharmacists also discovered a few patients whose renal function was never assessed before or during treatment. Prescribers agreed to have the appropriate lab work performed. Unfortunately, one physician's nurse refused to provide the requested laboratory values stating that there was no need for the lab work since "the patient had been on the medication for a long time and was doing fine."