Nephrotoxicity in patients treated with aminoglycoside therapy

Clinical monitoring for nephrotoxicity is required for all patients being treated with aminoglycoside therapy.

Historic data have demonstrated lower rates of nephrotoxicity associated with tobramycin than with gentamicin when used as directed therapyFeig 1982Schentag 1981Smith 1980. However, there are no high-quality recent data to support this.

Aminoglycoside-induced nephrotoxicity is usually associated with prolonged treatment courses (longer than 5 to 7 days) and pre-existing kidney impairment. Multiple-daily dosing aminoglycoside regimens have a higher risk of nephrotoxicity. Aminoglycoside-induced nephrotoxicity is generally reversible.

Review the patient’s kidney function before starting an aminoglycoside; however, if the patient is critically ill, it is appropriate to administer an initial empirical dose without ascertaining kidney function. If therapy is ongoing, assess kidney function 2 to 3 times each week. More frequent monitoring may be required if kidney function is unstable or if there are signs of drug accumulation (ie increasing plasma concentrations). Decreasing aminoglycoside dosage requirements can be an early indicator of deteriorating kidney function.

If aminoglycoside-induced nephrotoxicity is suspected, stop the aminoglycoside and seek expert advice.