1229. Extended interval dosing of aminoglycosides in renal transplant patients
Session: Poster Abstract Session: Transplant Screenings and Evaluation and Empiric and Pre-Emptive Therapy
Friday, October 9, 2015
Room: Poster Hall
Background: Gram-negative infections have become a growing concern in transplant patients due to the limited number of treatment options with negative side effect profiles. Given the increase in antimicrobial resistance, aminoglycosides are antibiotics that are frequently used for the treatment of gram-negative infections. The extended interval dosing of aminoglycosides offers clinicians a method of monitoring aminoglycosides while maximizing bactericidal effects and minimizing toxicities. However, populations such as transplant patients were excluded from the nomogram. Our study evaluated the use of extended interval dosing of aminoglycoside antibiotics in renal transplant patients.

Methods: Patient electronic medical records were retrospectively reviewed to identify those who had received gentamicin or tobramycin from January 1, 2009 to September 30, 2014. Those who were ≥18 years of age, received a dose of aminoglycoside post renal transplant, and were not on renal replacement therapy were included. The primary outcome was aminoglycoside treatment related nephrotoxicity defined by features of the RIFLE criteria as indicated by increases in serum creatnine (SCr) and decreases in glomerular filtration rate (GFR) or urine output (UOP). The secondary outcome was the pharmacokinetic analysis of aminoglycoside treatment.

Results: A total of 28 patients were included in the analysis with a median baseline GFR of 50.2 mL/min/1.73 m2. There was no statistically significant difference in median GFR at end of therapy compared to the pre-treatment GFR prior to aminoglycoside exposure (30.9 mL/min/1.73 m2 vs. 33.6 mL/min/1.73 m2, p>0.05). Applying the RIFLE criteria to the change in GFR at end of therapy did not result in any risk or injury to patients. The median expected population elimination rate according to the equation Ke = (0.00239 x CrCl) + 0.014 was significantly higher than the median calculated Ke, (0.086 vs. 0.041, p<0.05).

Conclusion: The results of this study suggest extended interval dosing of aminoglycosides did not increase injury in renal transplant patients; however, the median elimination rate was reduced. Larger studies are required to confirm these results.

Arnold Decano, PharmD1, Tiffany Bias, PharmD, BCPS, AAHIVP1, Alden Doyle, MD, MPH2 and Gregory Malat, PharmD, BCPS3, (1)Pharmacy, Hahnemann University Hospital, Philadelphia, PA, (2)Division of Nephrology, Drexel University College of Medicine, Philadelphia, PA, (3)Surgery, Hahnemann University Hospital, Philadelphia, PA


A. Decano, None

T. Bias, None

A. Doyle, None

G. Malat, None

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