Medication dosing errors for patients with renal insufficiency in ambulatory care

Approximately 8.7 million (3%) Americans have various degrees of chronic renal insufficiency (CRI). Patients with CRI are susceptible to adverse drug events related to improper dose adjustment of drugs that are eliminated primarily unchanged through the kidney. Renal dosing errors are an important quality-of-care problem in the inpatient setting, yet little is known about dosing errors for patients with renal insufficiency in the outpatient setting.

Electronic records were queried to identify patients with CRI (estimated creatinine clearance < 50 mL/min) who visited the ambulatory care clinic at least once from January 1, 2003 through December 31, 2003.

Of the total of 224 patients identified with CRI, 157 (70%) received one or more of 17 drugs with high rates of renal elimination. A total of 207 drugs requiring dose adjustment were prescribed to these patients, and 52 (25%) were prescribed at an inappropriately high dose. For 127 (57%) of the 224 patients, CRI was not documented. Patients with documented CRI were equally likely to be prescribed an inappropriately high dose of a target drug.

Incorrect dosing of medications among patients with CRI is common in the ambulatory care setting. Strategies for preventing medication dosing errors can target the prescribing and monitoring stages of pharmaceutical care.