Hypoalbuminemia as a risk factor for amikacin nephrotoxicity

Hypoalbuminemia has been recently informed by us as a risk factor in aminoglycoside nephrotoxicity. Since amikacin has a low serum binding capacity to albumin, the present study was designed to determine if the higher risk of amikacin nephrotoxicity in patients with hypoalbuminemia was due to low serum albumin per se or to malnutrition. One-hundred and thirteen ward patients who received endovenous amikacin for greater than 36 hours were studied prospectively. All were evaluated for the following factors: age, sex, diagnosis, serum creatinine, serum albumin, and nutritional status. They were followed with serum creatinine twice a week until cessation of therapy. Amikacin pharmacokinetics was studied in 11 subjects: 6 patients had a serum albumin less than 3.0 g/dL and 5 greater than 3.0 g/dL, but there were no differences in age, sex, weight, diagnosis, arterial pressure and nutritional status. The overall incidence of toxicity was 11%. In patients with serum albumin less than 3.0 g/dL it was 17.3% and in those greater than 3.0 g/dL it was 2.2%, p less than 0.05. There was no difference in the nutritional status between toxicity and non-toxicity groups. In the pharmacokinetic study, the peak levels obtained one hour after amikacin administration were higher in patients with serum albumin less than 3.0 g/dL than in those with normal serum albumin (12.7 +/- 1.6 vs 9.0 +/- 1.2, p less than 0.002). In conclusion hypoalbuminemia is a risk factor in aminoglycoside nephrotoxicity regardless of the nutritional status.