The diabetes drug metformin, perhaps better known by the brand name Glucophage, is no more likely than other diabetes drugs to cause lactic acid build-up, a potentially fatal chemical disturbance, new research reveals.
The diabetes drug metformin, perhaps better known by the brand name Glucophage, is no more likely than other diabetes drugs to cause lactic acid build-up, a potentially fatal chemical disturbance, new research reveals. Compared with other diabetes drugs, metformin has been shown to reduce death rates in patients with type 2 diabetes, Dr. Shelley R. Salpeter from Stanford University School of Medicine in California and colleagues note in their article. However, because it is believed to increase the risk of lactic acid build-up, metformin is not recommended for use with other chronic conditions that may raise the risk, such as heart, kidney, lung, and liver disease. “These restrictions significantly reduce the number of patients who could benefit from metformin treatment,” they write. On the other hand, the “true incidence of fatal and nonfatal lactic (acid build-up) associated with metformin use is not known.” In a study reported in the Archives of Internal Medicine, Salpeter and colleagues analyzed data from “all known prospective comparative trials and observational studies” lasting at least 30 days that evaluated metformin therapy alone or in combination with other treatments. They failed to find a single case of fatal or nonfatal lactic acid build-up among 194 trials involving thousands of patients treated with metformin for many years. Moreover, when they reviewed 56 additional trials excluded from the initial analysis because they lasted less than 1 month, still no cases of acid build-up related to metformin were found. In addition, there was no evidence that metformin raised acid levels any more than other diabetes drugs. “Metformin has been implicated as a cause of lactic (acid build-up) because treatment with a related (drug), phenformin, had been associated with several cases,” the researchers note. Phenformin was taken off the market in 1977. Despite their similarities, phenformin’s chemical structure is markedly different from metformin’s. Unlike phenformin, metformin does not enhance the production of lactic acid. (Source: MEDline Plus, Reuters, Archives of Internal Medicine, November 2003)