A practical approach enabling staff pharmacists to prospectively review and dose aminoglycoside therapy

Abstract

A simple and effective approach for staff pharmacists to prospectively review and dose aminoglycoside therapy is presented. A departmental policy was established requiring pharmacists to review each adult aminoglycoside order for appropriateness by means of a written audit form. Specific patient data and the aminoglycoside dose is obtained from an antibiotic order form and the patient's creatinine clearance is estimated using a modified Cockcoft and Gault equation. Proper initial dosage regimens are assessed by use of a modified Sarubbi and Hull nomogram or an in-house developed pharmacokinetic software program. The results demonstrate pharmacists were required to intervene in 26.8% of adult aminoglycoside orders. To determine if the percentage of pharmacist intervention changed over time, the results were compared to a sample period selected almost two years later. The percentage of pharmacists intervention was almost identical (25.3%). In both groups, over 90% of the pharmacists's dosing recommendations were accepted by the physician. The outcome of pharmacist's reviews were analyzed during the first study period. In courses of therapy with dosages recommended by pharmacists, therapeutic, non-toxic concentrations of gentamicin and tobramycin (peak 5-10 micrograms/ml, trough less than 2 micrograms/ml) comprised 47/54 (87%) of the interpretable levels. Patients judged by the pharmacist to have an appropriate dose during the initial review had 85/119 (71.4%) of interpretable serum levels in the therapeutic, non-toxic range. Without benefit of a formalized pharmacokinetic service, this program enables all staff pharmacists to perform a review of aminoglycoside therapy which ensures an appropriate initial dosage regimen. The completed aminoglycoside initial audit form serves as a communication tool as well as documentation for the department's quality assurance program.