Drug dosage adjustment in hospitalized patients with renal impairment at Tikur Anbessa specialized hospital, Addis Ababa, Ethiopia.

Background: Dose adjustment for certain drugs is required in patients with reduced renal function to avoid toxicity as many drugs are eliminated by the kidneys. The aim of this study was to assess whether appropriate dosage adjustments were made in hospitalized patients with renal impairment.
Methods: A prospective cross-sectional study was carried out in the internal medicine wards of Tikur Anbessa Specialized Hospital. All patients with creatinine clearance ≤ 59 ml/min admitted to hospital between April and July, 2013 were included in the analysis. Data regarding serum creatinine level, age, sex and prescribed drugs and their dosage was collected from the patients' medical records. Serum creatinine level ≥ 1.2 mg/dL was used as a cutoff point in pre-selection of patients. The estimated creatinine clearance was calculated using the Cockcroft- Gault (CG) equation. Guideline for Drug prescribing in renal failure provided by the American College of Physicians was used as the standard for dose adjustment.
Results: Nine percent (73/810) of medical admissions were found to have renal impairment (CrCl  ≤ 59 ml/min). There were 372 prescription entries for 73 patients with renal impairment. Dose adjustment was required in 31 % (115/372) of prescription entries and fifty eight (51 %) prescription entries requiring dose adjustment were found to be inappropriate. Of 73 patients, 54 patient received ≥ 1 drug that required dose adjustment (median 2; range 1-6). Fifteen (28 %) patients had all of their drugs appropriately adjusted while twenty two (41 %) patients had some drugs appropriately adjusted, and seventeen (31 %) of patients had no drugs appropriately adjusted. No patients were documented to have received dialysis.
Conclusion: The findings indicate that dosing errors were common among hospitalized patients with renal impairment. Improving the quality of drug prescription in patients with renal impairment could be of importance for improving the quality of care.