Risk factors for toxicity in elderly patients given aminoglycosides once daily

OBJECTIVE:To determine the risk factors for aminoglycoside toxicity in the elderly. DESIGN:Prospective observational study. SETTING: Acute care teaching hospital serving predominantly veterans. PARTICIPANTS: Consecutive patients aged 70 years and over receiving aminoglycosides. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Thirteen (15%) of 88 patients developed aminoglycoside-related nephrotoxicity and 3 (3.4%) developed otovestibular toxicity. Multivariate analysis showed that increasing duration of aminoglycoside therapy was the only factor significantly associated with development of toxicity. Elevated baseline serum creatinine level (p = .02) and use of allopurinol (p = .03) were risk factors specifically for nephrotoxicity. Only 2 (3.9%) of 51 patients receiving aminoglycosides 7 or fewer days developed nephrotoxicity, as compared with 11 (30%) of 37 receiving the drugs for 8 to 14 days and 4 (50%) of 8 treated for more than 14 days. CONCLUSIONS:Although toxicity is common in elderly patients treated with aminoglycosides, limiting the duration of aminoglycoside therapy to less than a week can substantially reduce risk of toxicity.