Pharmacokinetics of gentamicin in hemodialysis patients: a comparative study between diabetic and non-diabetic patients

Diabetic nephropathy is one of the leading causes of end-stage renal disease (ESRD). There is some evidence that differences in extracellular fluid volume and capillary permeability do exist between diabetic and non-diabetic patients. This may have an impact on the gentamicin volume of distribution and clearance and thus dosing regimen. The pharmacokinetic parameters of gentamicin [volume of distribution (Vd), clearance (CL), elimination rate constant (K), and half life of elimination (t ½ )] were studied before hemodialysis in 20 non-diabetic patients (controls) and 20 diabetic patients, in addition to its hemodialysis clearance. There were no statistically significant differences in Vd, CL, K, and t ½ of gentamicin between the control and diabetic group. Therefore, a composite Vd of 0.25 l/kg and clearance of 0.063 ml/min/kg are suggested for dose calculation for both groups of patients. The mean hemodialysis clearance of gentamicin was higher in the diabetic (87.3 ml/min) than the control group (68.5 ml/min), comparing means by the unpaired t -test ( P = 0.018). In conclusion, the same method can be used to calculate the loading dose of gentamicin in ESRD patients between dialysis sessions in both controls and diabetics, whereas, diabetics are expected to receive a higher replacement dose after the end of dialysis.