Metformin can be pulled from market if prescribers don’t develop a better understanding of the prescribing guidelines. According to a report published in the February 25th issue of the Archives of Internal Medicine, many hospitalized patients receive metformin therapy despite having contraindications that increase their risk of lactic acidosis.
The product labeling for metformin identifies several clinical factors or patient characteristics that increase the lactic acidosis risk. However, the current findings suggest that many physicians are unaware of these prescribing guidelines.
In more than one-quarter of hospital admissions involving metformin therapy, at least one dose of the drug was given despite the presence of absolute contraindications, Dr. Amy T. Calabrese, from the University of Pittsburgh, and colleagues state. In fact, treatment with the drug is actually continued in many cases with contraindications.
Dr. Calabrese’s team analyzed data from 263 hospitalizations in which metformin therapy was given. The most common contraindication was elevated serum creatinine, which was present or developed during 32 admissions. Furthermore, in only eight of these 32 patients was the drug appropriately discontinued.
The most common precautionary condition violated was the use of metformin in patients receiving cationic agents, which occurred in 97 admissions, the researchers note.
Due to the retrospective nature of the study, the problem of inappropriate metformin prescribing practices may actually be more widespread than indicated, the investigators point out.
"It is essential that physicians develop a better understanding of the prescribing guidelines for metformin," the authors state. Not only will this help reduce the risk of lactic acidosis, but it may also prevent metformin from being pulled from the market–which has happened with several other drugs that were used in patients with labeled contraindications. Arch Intern Med 2002;162:434-437.