Tobramycin Drug Monitoring

Note

Monitor creatinine at least weekly and more often if concentrations are elevated or other signs of renal dysfunction arise

Discontinue if any signs of ototoxicity (tinnitus, fullness in ears, dizziness)

Serum Concentration Monitoring

  • For most patients and indications, no concentrations are necessary, unless patient suspected at high risk for development of nephrotoxicity or renal dysfunction, or duration of treatment more than 5 days

    • In these cases check trough concentration prior to any dose to ensure that it is less than 1 mg/L
  • In cases where there is concern regarding treatment efficacy due to lack of response or severe infection treated with monotherapy, for cystic fibrosis (CF) or febrile neutropenia:

    • Draw TWO concentrations, one 2 to 3 hours and one 6 to 8 hours after first dose

If plan is to discontinue tobramycin pending 48-hour culture results, no concentrations are required unless indicated for renal dysfunction

If plan is to continue antibiotics beyond 48 h culture results, draw a 22 hour concentration on all neonates regardless of ordered dosing interval

  • If 22 h concentration is:
    • 1.2 mg/L or less: Give every 24h
    • 1.3 to 2.6 mg/L: Give every 36h
    • 2.7 to 3.5 mg/L: Give every 48h
    • 3.6 mg/L or more: Hold next dose, repeat concentration in 24 hours. Base interval on time to reach trough concentration less than 2 mg/L. Repeat 22h concentration if therapy continues beyond 7 days

Obtain drug concentrations with the third or fourth dose. Peak serum concentrations are drawn 30 minutes after the end of an IV infusion or one hour post-IM injection

  • Peak concentration are: 5 to 10 mg/L and 12 to 15 mg/L in cystic fibrosis

  • Trough concentrations are drawn just prior to the next dose and should be less than 2 mg/L

Concentrations are typically not required

If done, targets are:

  • Peak 3 to 5 mg/L and trough less than 2 mg/L