Medical Error: Frequency of Inappropriate Metformin Prescriptions
Medical error is well documented as the 3rd leading cause of death in the U.S. and medication errors alone are the 4th leading cause of death. These numbers are based on studies in hospitals where medical error is routinely underreported. They do not include outpatient deaths which probably exceed inpatient deaths. As an example, here is a widely prescribed drug that 25% of the time is prescribed, even though there is a black box warning on the package that the patient should not be receiving this drug. Effects can be deadly as noted in:
Horlen, C. et al. Frequency of Inappropriate Metformin Prescriptions. JAMA Vol. 287 No. 19, May 15, 2002.
“Metformin is commonly used in the management of type 2 diabetes. More than 25 million prescriptions for metformin were written in 2000, making it the most commonly prescribed branded diabetes medication in the United States. Metformin has been associated with the development of lactic acidosis, and since its initial marketing in 1995 the US Food and Drug Administration (FDA) has required a “black box” warning in the package insert. Labeled contraindications include renal dysfunction and congestive heart failure (CHF) requiring pharmacologic treatment. We sought to determine the frequency of metformin use in a sample of patients with these 2 primary contraindications to therapy…
“In our review, almost one quarter of patients with a prescription for metformin had 1 or more absolute contraindications. Several recent studies in Europe have documented similar rates of inappropriate metformin prescribing. Adverse event reports suggest the incidence of metformin-associated lactic acidosis is between 1 in 10000 to 1 in 100000 patient-years. In the first 14 months after its release in the United States, the FDA received 47 confirmed cases of lactic acidosis associated with metformin, with a 42% mortality rate. More than 90% of patients had relative or absolute contraindications to metformin.”