Comparing the effect of multiple - dose and once - daily regimens of gentamicin therapy on fraction excretion of magnesium

This study was designed to compare the influence of ordinary (multiple-dose) and once-daily administration of gentamicin on tubular nephrotoxicity based on the urinary excretion of magnesium (Mg) as an indicator for this type of side effect. Thirty-two hospitalized patients, who were assigned to receive at least 5-days treatment with gentamicin at the infectious disease ward of Imam Hospital in Tehran, were prospectively studied. Seventeen patients received multiple-doses of gentamicin per day and 15 patients received once-daily regimen. At the beginning and at the end of of gentamicin therapy, blood urea, serum creatinine (Cr) and Mg levels were measured. Additionally 24-hour urine samples were collected for measurement of urinary volume, creatinine and Mg excretions. In both treatment groups serum Mg concentration was significantly lower and fraction excretion of (FEMg) were considerably higher at the end of gentamicin therapy compared with the beginning of the treatment. However, the serum and urinary creatinine levels did not change significantly in the two groups