Comparative study of ototoxicity and nephrotoxicity in patients randomly assigned to treatment with amikacin or gentamicin.

Fifty-four patients treated with gentamicin and 52 patients treated with amikacin were evaluated for nephrotoxicity and ototoxicity in a prospective, randomized, blinded comparative trail. According to our definition of nephrotoxicity (an increase in serum creatinine levels to at least 50 percent and 0.5 mg/dl above the baseline value), nephrotoxicity occurred in eight (15 percent) of the patients who were treated with gentamicin and none of the patients who were treated with amikacin (p = 0.006). Using several other definitions of nephrotoxicity, the differences in incidence between the treatment arms were not significant. Nephrotoxicity appeared to be associated with impaired baseline renal function, greater age, and the presence of bacteremia. Ototoxicity occurred in six (11 percent) of the 54 gentamicin-treated patients; auditory toxicity occurred in three patients, and toxic changes were observed in three of the 33 patients who could also be evaluated for vestibular toxicity. Similarly, ototoxicity was observed in seven (13 percent) of the 52 amikacin-treated patients; auditory toxicity occurred in four patients, and of the 34 patients who could also be evaluated for vestibular toxicity, three exhibited vestibular toxicity without auditory toxicity are one experienced vestibular effects in addition to those affecting the cochlea. We observed a modest association of ototoxicity with nephrotoxicity and with an elevated mean trough aminoglycoside serum level. The results of this study indicate that amikacin may be less nephrotoxic than gentamicin in humans; however, the broad applicability of this finding to other patient populations is uncertain.