Drug dosage adjustments according to renal function at hospital discharge

Adequate dosing of medication in renal impairment to prevent hospitalizations and adverse reactions is a growing concern in the aging society. There are several dosing guidelines available, but structural use is uncommon.

To perform a retrospective analysis of the incidence of required versus implemented dosage adjustments according to guidelines in patients with renal insufficiency at discharge and evaluate specific determinants responsible for the percentage of overlooked dosage adjustments.

Medication and laboratory data were collected from patients at discharge during February and November 2004. For patients with a calculated creatinine clearance less than 51 mL/min/1.73 m(2), the necessity for dosage adjustments was evaluated by pharmacists. All data were collected for further research and subsequent statistical analysis.

At discharge, 237 of 647 (36.6%) patients had a calculated creatinine clearance less than 51 mL/min/1.73 m(2). Dosage adjustment based on renal function was necessary in 411 of 1718 (23.9%) of prescriptions. These adjustments were performed in 242 (58.9%) prescriptions and not performed in 169 (41.1%) cases. The risk of not adjusting the dosage was significantly associated with serum creatinine levels greater than 1.71 mg/dL and creatinine clearance less than 35 mL/min/1.73 m(2) (p < 0.05). The risk of not adjusting the dosage was also significantly associated with drugs producing severe consequences when dosing guidelines were overlooked (p < 0.05).

In patients with a calculated creatinine clearance less than 51 mL/min/1.73 m(2), dosing according to their renal function can be improved. Because of the need and the association found in this study, an alert system could help prescribers and pharmacists to adapt drug dosage in patients with renal impairment.