Neonatal Drug Therapy Manual

Tobramycin

Disclaimer: Official controlled document is the CHEO and Ottawa Hospital online copy. It is the responsibility of user to ensure that any paper copy version is the same as the online version before use.

Alternate Name(s): 
Tobrex
Classification: 
Antibiotic (aminoglycoside)
Original Date: 
September 2003
Revised Date: 
December 2020
Indications: 
  • Treatment of documented or suspected infections caused by susceptible Gram (-) bacilli including Pseudomonas aeruginosa. 
Administration: 
  • IV Intermittent infusion: over 30 minutes
Dosage: 

Gestational Age and Post-Natal Age

Dose* Therapeutic Drug Levels

 

 

 

Preterm 

(< 36 weeks  GA)

0 - 14 days < 28 weeks GA 3 mg/kg/dose Q24h

Traditional Dosing (Pre and Post levels obtained after 48 hours if renal function remains normal)

 

 

  • Pre (0 - 30 minutes before dose): 0.5 - 2 mg/L

AND

  • Post (30 minutes after end of a 30 minutes infusion): 5 - 10 mg/L

 

29 - 36 weeks GA 3.5 mg/kg/dose Q24h
> 14 days < 28 weeks corrected GA 3 - 3.5 mg/kg/dose Q18h
> 29 weeks corrected GA 3 - 3.5 mg/kg/dose Q12h

 

Gestational Age and Post-Natal Age Dose* Therapeutic Drug Levels

 

 

 

Term (> 37 weeks GA)

 

 

0 - 7 days

3 - 3.5 mg/kg/dose Q18h

Traditional Dosing

(Pre and Post levels obtained after 48 hours if renal function remains normal)

 

  • Pre (0 - 30 minutes before dose): 0.5 - 2 mg/L

                           AND

  • Post (30 minutes after end of a 30 minutes infusion): 5 - 10 mg/L
0 - 7 days (Abnormal Renal Function **, Acute HIE/Asphyxia) 3 mg/kg/dose x 1 Random Tobramycin level 24 hours after initial dose, if < 2.0 mg/L may repeat dose. Consult pharmacist for further dosing interval recommendations

 

 

 

> 7 days

 

5 mg/kg/dose Q24h

Extended Interval Dosing (Preferred with normal renal function)

(Pre level only done prior to 3rd dose)

 

  • Pre (0 - 30 minutes before dose): < 0.3 mg/L
2.5 mg/kg/dose Q8h

Traditional Dosing

Pre and Post levels obtained on Day 3.  For dosage adjustment and timing of levels in renal impairment, consult pharmacist

* For frequency adjustment due to renal dysfunction, consult clinical pharmacist.

** This would include neonates with suspected, possible or confirmed hypoxic ischemic events, fluid imbalance, possible or suspected renal thrombosis, congenital renal anomalies or any other conditions that may be associated with transient or prolonged renal dysfunction.

Side Effects: 
  • Hematologic: anemia, granulocytopenia, thrombocytopenia
  • Otic: vestibular/auditory toxicity
  • Renal: nephrotoxicity, increase risk with concurrent use of nephrotoxic drugs (eg. furosemide, indomethacin) 
Parameters to Monitor: 
  • Renal: serum creatinine, urea, urine output
  • Therapeutic drug levels: see tables

** When checking level, administer next dose as scheduled. Do not wait for levels to be reported unless otherwise advised

Reconstitution and Stability: 

IV intermittent infusion:

CHEO:

  • Tobramycin 40 mg/mL (doses < 10 mg)
    • Take 1 mL (40 mg) and add to 39 mL D5W
    • Final concentration: 1 mg/mL
  • Tobramycin 40 mg/mL (doses > 10 mg)
    • Take 1 mL (40 mg) and add to 3 mL D5W or 0.9% NaCl
    • Final concentration: 10 mg/mL

TOH:

  • Tobramycin 40 mg/mL
    • Take 1 mL (40 mg) and add to 39 mL D5W

    • Final concentration: 1 mg/mL

Compatibility: 

- Solutions Compatible: D5W, D10W, 0.9% NaCl, dextrose-saline combinations

- Y-site Compatible: acyclovir, dexmedetomidine, fentanyl, fluconazole, heparin (low concentrations of 0.5 to 1 unit/mL that are used to maintain IV line patency), hydromorphone, midazolam, milrinone, morphine, TPN (amino acids- dextrose)

- Incompatible: heparin (concentration greater than 1 unit/mL), indomethacin, piperacillin/tazobactam, SMOF

  • Direct contact of a penicillin antibiotic (eg, ampicillin, piperacillin) with an aminoglycoside (gentamicin, tobramycin) may cause inactivation.  Rinse thoroughly between both administration if given via the same line. 

 

Notes: 

Traditional Dosing: Intermittent dosing initially based on gestational and post-natal age.  Dose modifications may be required based on pre and post levels obtained after 48 hours.

Extended Interval Dosing: Initial dosing based on Q24 hours schedule to achieve high peak levels in neonates > 7 days of age with no documented or possible abnormal renal function.  Dosage modifications may be required based on pre-dose level obtained at 72 hours.  This dosing is not to be used for preterm neonates.

References: 

-Taketomo CK, Hodding JH, Kraus DM. Pediatric and Neonatal Dosage Handbook 22nd Editions. Hudson: Lexi-Comp Inc.; 2015

- Low YS, Tan SL, Wan A. Extended-Interval Gentamicin Dosing in Achieving Therapeutic Concentrations in Malaysian Neonates. J Pediatr Pharmacol Ther. 2015. Mar-Apr, 20 (2): 119-127

-American Society on Health-System Pharmacists (ASHP). Handbook on Injectable Drugs. 19thEdition. Bethesda: American Society of Health-System Pharmacists; 2017

The information contained on this website is provided for informational purposes only, as a guide to assist physicians, nurses and other healthcare providers in deciding on the appropriate care required for a particular patient. At all times, physicians, nurses and other healthcare providers must exercise their independent clinical judgment, based on their knowledge, training and experience, taking into account the specific facts and circumstances of each patient, when deciding on the appropriate course of investigation and/or treatment to recommend in a particular clinical situation.

CHEO has made every effort to ensure that the information contained on this website is as current and accurate as possible. However, changes can occur due to ongoing research and the constant influx of new information. Where possible, hospitals and healthcare practitioners should verify the information before acting on it.

Reliance on any information in this website is at the user's own risk. CHEO is not responsible or liable for any harm, loss or other consequences from the use or misuse of the information on this website.