Renal function impairment gentamicin

Gentamicin is an aminoglycoside. All aminoglycosides tend to be nephrotoxic and ototoxic. The dose must be reduced and serum concentrations must be monitored in patients with impaired renal function. Concomitant administration of aminoglycosides and other nephrotoxic drugs, such as certain diuretics, ciclosporin, teicoplanin and vancomycin should be avoided. 

The normal half-life of aminoglycosides in serum is 2-3 hours, increasing to 24-48 hours in patients with significant impairment of renal function. Aminoglycosides are only partially and irregularly removed by hemodialysis—eg, 40-60% for gentamicin—and even less effectively by peritoneal dialysis. 

Careful tailoring of the dose can prevent nephrotoxicity. In 89 critically ill patients with a creatinine clearance over 30 ml/minute who were treated with gentamicin or tobramycin 7 mg/kg/day independent of renal function, with subsequent doses chosen on the basis of the pharmacokinetics of the first dose, signs of renal impairment occurred in 14% in all survivors renal function recovered completely and hemofiltration was not needed (104). 

The decision of which regimen to use depends on the perceived risk versus benefit. For example, a 2-week course of gentamicin in an elderly patient with renal impairment may be associated with ototoxicity, worsening renal function, or both. Furthermore, the 2-week regimen is not recommended for patients with complications such as extracardiac foci. On the other hand, a 4-week course of penicillin alone generally entails greater expense, especially if the patient remains in the hospital. Monotherapy with once-daily ceftriaxone offers ease of administration, facilitates home health care treatment, and may be cost-effective. ... 

Other reports similarly describe unusually low gentamicin levels in patients with impaired renal function, given carbenicillin, piperacillin," or ticarcillin. > >" The half-life of gentamicin has been reported to be reduced by carbenicillin or piperacillin by about one-half or one-third. >">" Similarly, unusually low tobramycin levels have been reported in patients with impaired renal function, who were given carbenicillin, piperacillin or ticarcillin."... 

Information is limited, but patients should be monitored for increased digoxin effects if gentamicin is given, especially those with diabetes or any other patient with impaired renal function. Initially, checking pulse rate is probably adequate. There seems to be no information about other parenteral aminoglyeosides. 

Drug overdose After massive gentamicin overdose in a 14-month-old girl, who received gentamicin 56 mg/kg for empirical treatment of fever, the peak serum gentamicin concentration was 89 mg/1 [24 ]. She was treated with 4 horns of hemodialysis 4 hours after the overdose her renal function remained stable throughout and there was no evidence of renal or hearing impairment 3 months later. 

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