Assessment of Renal Function in Duchenne Muscular Dystrophy Patients Treated with Gentamicin

Abstract

Recently, high dose gentamicin (GM) has started to be used for the treatment of Duchenne muscular dystrophy (DMD). Previously, since the intravenous infusion of GM for 1h once a week at a dose of 7.5 mg/kg/day had caused no significant adverse events in a course of therapy lasting 6 months, we decided to try conducting such therapy for four courses in the present study. We continuously assessed renal function by monitoring serum creatinine, serum cystatin C (Cys-C), serum urea nitrogen (BUN), urinary β₂-microglobulin and urinary N-acetyl-β-D-glucosaminidase (NAG) activity. Serum creatinine levels were found to be much lower than the normal range, while, at 0.65 to 0.78μg/mL, serum Cys-C levels, were within the normal range and so was BUN, suggesting that the glomerular filtration rate in the DMD patients receiving GM therapy was being maintained in the normal range. Therapeutic drug monitoring of GM indicated that it was being rapidly eliminated from the systemic circulation though a slight elevation of urinary NAG activity in 1 patient indicated the possibility of impaired renal proximal tubules. It will thus be necessary to optimize our patient management strategy.