ABSTRACT

Background: Use of gentamicin places patients at risk of developing drug-induced nephrotoxicity, requiring special consideration to be given to serum creatinine monitoring and therapeutic drug monitoring (TDM).

Objectives: To evaluate the prevalence of nephrotoxicity without the availability of TDM.

Methods: A prospective study designed was used to recruit patients, 18 years and older who were to receive intravenous gentamicin administration between July 2013 and July 2014 at the University Hospital of the West Indies. Data collected included demographics, type of infection, gentamicin dose regimen, concomitant drugs and serum creatinine. Nephrotoxicity was defined as 1.5 times or more increase in serum creatinine concentration above baseline.

Results: A total of 11 patients were included in the study; 6(55%) were male, median age was 51 years (range: 33 - 84 years). All patient had normal baseline serum creatinine, median 56 (range: 22-94) µmol/L and had regular monitoring of serum creatinine during therapy.  The median gentamicin dose was 160 mg/day (range: 50-240 mg/day) and median treatment length was 8 days (range: 5-30 days).  Evidence of nephrotoxicity was observed in 6 (55%) patients by day 7 of therapy.  All patients had at least one risk factor predisposing them to nephrotoxicity including prolonged therapy (10/11), multiple daily dosing regimen (8/11), receiving concomitant nephrotoxic drugs (9/11) and age (6/11).   

Conclusion: Although vigilant monitoring of serum creatinine is useful for safety monitoring, with most patients experiencing some level of nephrotoxicity and having at least one predisposing risk factor, consideration should be given to the implementation of TDM.