Evaluation of an extended-interval gentamicin dosing protocol in neonates ≤ 33 weeks gestational age

A project presented to the Department of Physician Assistant of Wichita State University in partial fulfillment of the requirements for the degree of Master of Physician Assistant.We evaluated a simple, weight-based, extended-interval dosing (EID) gentamicin protocol specifically in neonates with gestational age ≤ 33 weeks, and its impact on sub-therapeutic peaks, elevated troughs, and simplification of dosing and monitoring as compared to a weight-based, multiple daily dose (MDD) protocol. Methodology. This study evaluated all infants with GA ≤ 33 weeks receiving gentamicin 1-year before EID protocol implementation in Jan 2002, and 1-year after. The MDD protocol used 2.5mg/kg every 8, 12, 18, or 24 hrs based on weight and age groupings. The EID protocol uses 3mg/kg q24 hours if weight < 1500gm and 4mg/kg if weight ≤ 1500gm. Desired trough was ≤ 2.0 mcg/ml and peak was 5 – 12 mcg/ml. Results. Characteristics were similar for the 123 MDD and 98 EID patients reviewed. The percentage of patients with at least 1 sub-therapeutic peak was lower with EID (7% vs. 20%, p