Medication Dosing Error and Contributing Factors among admitted Patients with Renal Impairment in Jimma University Specialized Hospital, Southwest Ethiopia

Abstract

Medication dosing errors are among the frequently encountered medication problems in patients with renal impairment. Dose adjustment becomes very important when dealing with medications with potential nephrotoxicity and/or elimination through renal excretion or metabolism. Objective: The aim of this study was to assess the medication dosing errors with drugs of potential nephrotoxicity and/or elimination through renal excretion or metabolism and contributing factors among admitted patients with renal impairment in Jimma University Specialized Hospital. Methodology: A cross-sectional quantitative study was carried out at pediatrics, surgical and medical wards of Jimma University Specialized Hospital from February 7 to April 10, 2011. Patients‟ clinical, laboratory findings and medications prescribed to patients with renal impairment were abstracted from their medical cards using pretested data abstraction format. Calculated creatinine clearance < 50 ml/min was considered for selection of patients with renal impairment. Appropriateness of dosing was evaluated based on standard drug treatment guidelines. Subjective data were also collected from prescribers in the selected wards using self administered questionnaire to assess contributing factors for medication dosing error. The data obtained was analyzed using SPSS version 16.0. Descriptive statistics and logistic regression were undertaken to assess medication dosing errors and their contributing factors. The significance level for the analysis was 0.05. Results: A total of 86 patients with calculated creatinine clearance <50 ml/min were included in the study. They were prescribed a total of 406 lines of prescription, of which 371(91.38%) were medications with potential nephrotoxicity and/or elimination through renal excretion or metabolism from which 85 (22.91%) lines of prescriptions were inappropriately dosed. Moreover, 52(60.5%) of the patients had at least one medication dosing error. Forty seven (55.29%) of the 85 dosing errors were associated with increase or decrease in frequency of the drug regimen; the rest being associated with dose or both dose and frequency errors. The most inappropriately dosed medications were furosemide, diclofenac, salbutamol, amlodipine and digoxin. Sex of the patient, hospital stay, and complexity of the regimen were significantly associated with the medication dosing error. Conclusion and recommendation: In our present study, medication dosing errors were prevalent (22.91%) among admitted patients with renal impairment. Errors were mainly associated with dosage frequency of cardiovascular drugs such as furosemide, amlodipine and digoxin. Continued medical education in the field of clinical pharmacokinetics and renal drug dosing is required.