Revision of Tobramycin-2024 from Oct 7, 2024

Dosing: Adult Antimicrobial Dosing, Non-dialysis

For UCSF pharmacists, access the pharmacy guidance manual click here

Do not use high-dose extended interval dosing strategy (using Hartford nomogram) in the following populations:

- Cr Cl ≤ 20 ml/min

- Aminoglycoside t ½ > 4.5 hours

- Patients with burns > 20% total burn surface area (TBSA)

- Ascites

- Cystic Fibrosis (CF) patients

- Pregnancy (outside of surgical prophylaxis)

- Spinal cord injury

High-dose extended dosing strategy (Hartford nomogram):

Indication CrCl > = 60 mL/min 40-59 mL/min 21-39 mL/min CrCl < = 20 mL/min Comments
Cystitis  5 mg/kg x 1  5 mg/kg x 1 5 mg/kg x 1 Use conventional/traditional dosing No nomogram or levels needed
Other infecions (exclude CF) 7 mg/kg IV q24h 7 mg/kg IV q 36h 7 mg/kg IV q 48h Use conventional/traditional dosing

Obtain 6-14 hour random gentamicin level after first dose to inform future dosing interval

Consider consulting pharmacy to assist with suggested dosing and monitoring

Use Harford dosing nomogram

Do not use this dosing in CF patients

Hartford dosing nomogram (gentamicin/tobramycin 7 mg/kg)

hartford.jpg

Urban Craig (5 mg/kg) dosing nomogram:

 

Chart

Description automatically generated

Conventional/traditional dosing:

Please consult pharmacy to help with dosing and monitoring plan.  Below are suggested peak and trough goals based upon infection:

Conventional/traditional dosing

Gentamicin/Tobramycin 

Infection 

Extrapolated  

Peak Goal  

Extrapolated  

Trough Goal  

Abdominal Infections (including peritonitis)  

6-8 

< 1 (0.5) 

Bacteremia 

6-8 

< 1 (0.5) 

Empiric therapy for Cystic Fibrosis (if cannot do high-dose extended interval dosing)

Extended interval preferred but if impaired renal function consider 8-12 for peak and < 1 (0.5) for trough  

Endocarditis 

Gram positive (‘synergy in divided doses’) * 

Gram negative 

 

3-4 

8-10 

 

< 1 (0.5) 

< 1 (0.5) 

Neutropenic Fever 

6-10 

< 1 (0.5) 

Pneumonia 

8-10 

< 1 (0.5) 

Skin and soft tissue 

infections 

6-8 

< 1 (0.5) 

Urinary tract infections (including pyelonephritis) 

4-6 

< 1 (0.5) 

 

 

 

 

Cystic fibrosis (CF) patients:

Prior to choosing a dosing regimen the clinical pharmacist should review the patient’s previous aminoglycoside  regimen(s) to determine if information from previous courses of therapy can aid n selecting dosing for a new course of treatment.  Please contact pharmacy for assistance.  If no history of previous doses and levels, then follow the below:

Indication CrCl > = 60 mL/min 40-59 mL/min 21-39 mL/min CrCl < = 20 mL/min Comments
CF exacerbation 10 mg/kg IV q 24h 10 mg/kg IV q 36h 10 mg/kg IV q 48h Use conventional/traditional dosing

Do not use Hartford nomogram

With first dose, obtain two serum concentrations 2 hours and 6 hours (10 hours in impaired renal function, elderly), counting from the start of the infusion. This typically allows for 2 half-lives to pass between levels. Periodically, it may help to have a third level (trough) if needed for additional calculations.  Consult pharmacy to assist.

Aminoglycoside for CF Target peak Target trough
Tobramycin 20-35 mcg/mL*  < 1 mcg/mL  

*There may be instances (e.g., elevated MIC) where the targeted peak may need to go up to 40- 60 mcg/mL - contact adult ID pharmacist.   

Dosing: Antimicrobial Dosing in Intermittent & Continuous Hemodialysis

Indication

Intermittent Hemodialysis

Continuous Hemodialysis
All indications

Use conventional/traditional dosing 

Consult pharmacy to assist 

Consult pharmacy to assist with dosing strategy

Dialysis Notes

Intermittent HD assumes high-flux hemodialysis. CRRT assumes CVVHD with ultrafiltration rate 2L/h and residual native GFR < 10 mL/min.

References: