Tobramycin

C. diff Risk

Low

Oral Bioavailability

NA

Approximate Cost

~ $15.00/day

Dosing

No adjustment necessary

General Information

Common Usage

Pseudomonal and other gram negative infections.

Inhaled form used in cystic fibrosis.

Drug Monitoring

Monitor creatinine at least 3 times/week. Discontinue if any signs of ototoxicity.

For Multiple daily dosing: Target Peak 4-10 ug/mL, Trough 1-2 ug/mL.

For Once daily: Target Trough <1 ug/mL.

NB: Trough level is 0-30min before a dose (usually pre-4th), and peak is 30-60min after dose infused (usually post-3rd).

In critically ill patients, check peak level after the 1st dose as volume of distribution and renal function may change rapidly.

Adverse Effects

Nephrotoxicity (non-oliguric)

  •  Avoid concomitant nephrotoxins

  •  Less common with once daily dosing

  •  Greater toxicity with longer duration and supratherapeutic trough levels

Vestibulocochlear toxicity

  • Irreversible

  • Require audiology testing if prolonged use

Can exacerbate neuromuscular blockade

  •  Contraindicated in patients with myasthenia gravis.

Major Interactions

Increased nephrotoxicity

  •  Amphotericin B

  •  Cyclosporine

  •  Cisplatin

  •  NSAIDS

  •  Contrast dye

  •  Vancomycin

Increased ototoxicity

  •  Furosemide

Neuromuscular blockade agents - Respiratory paralysis.

Additional Information

Formal audiology assessment if planning to use aminoglycoside for >7d or if symptoms develop.

Inform patient of risk of ototoxicity and to report any symptoms.

Pharmacology

Antimicrobial class: Aminoglycoside

Pregnancy category: D

Average serum half life: 2-3 hours

Biliary penetration: Moderate

CSF penetration: Poor

Lung penetration: Therapeutic

Urine penetration: Therapeutic