Antibiotic Dosing

Extended Dosing of Aminoglycosides  -  Gentamicin or Tobramycin

Initial dose is based on body weight.

Normal weight patients: 7mg/kg, based on actual body weight.

Obese patients (more than 20% above ideal body weight): 7mg/kg based on adjusted body weight:
Obese Dosing Weight = IBW + 0.4 (Actual BW - IBW)

Initial dose interval is based on patient's creatinine clearance.

Creatinine Clearance	Dosing Interval
>=60 ml/min	7 mg/kg every 24 hours
40-60 ml/min	7 mg/kg every 36 hours
20-40 ml/min	7 mg/kg every 48 hours
<20 ml/min	7 mg/kg then follow serial levels, give next dose when level <2 ug/ml.

Dosing based on serum levels:

Obtain a single serum level 6-14 hours after starting infusion of the first dose.

Use the nomogram to determine the interval for subsequent doses.

If the level is above the Q48 hr region of the nomogram, follow serial levels and give the next dose when the level is <2 ug/ml.