Gentamicin: Dose adjustment for renal impairment

  • Dosing recommendations are based on creatinine clearance calculated using the Cockcroft-Gault equation.
  • Do not use eGFR estimates (available on PAS) for drug dosing purposes (for more information  click here )
  • To calculate creatinine clearance (CrCl) using the Cockcroft-Gault equation, use the creatinine clearance calculator :
  • Accurate estimation of CrCl is only possible in patients with STABLE renal function. In patients with rapidly changing renal function (i.e. ACUTE renal failure), the serum creatinine levels will no longer provide a true reflection of renal function.
  • Dose adjustment may not be appropriate in ACUTE renal impairment secondary to SEPSIS. In this case it is important to treat the infection aggressively for the first 24hrs and re-check renal function before reducing the dose accordingly.
  • (In 'acute on chronic' renal impairment the initial dose should correspond to the previous level of chronic renal impairment).

Which gentamicin dosing regimen is being used?

Once Daily Dosing (preferred - unless contraindicated see local policy)

For bd or tds dosing when once-daily dosing not appropriate i.e.

  • Endocarditis
  • Pregnancy
  • Major burns
  • Ascites
  • Osteomyelitis
Crcl (ml/min) Dose
20 – 50

80mg every 12 hours (60mg if <60kg)

10 – 20

80mg every 24 hours (60mg if <60kg)

<10 80mg every 48 hours (60mg if <60kg)


Close monitoring of serum levels recommended and adjust dose accordingly

Refer to renal pharmacist for advice on dosing in haemodialysis and peritoneal dialysis.

Refer to critical care pharmacist for advice on dosing in CVVH.