Tobramycin

C. diff Risk

Low

Oral Bioavailability

NA

Approximate Cost

Dosing

Use Adjusted Body Weight for obese patients (BMI ≥30 kg/m2)

Once Daily Dosing
5-7 mg/kg IV every 24 hr

Multiple Daily Dosing
1.5-2 mg/kg IV every 8 hr

Recommend dosing per Pharmacy

Cystic Fibrosis
300 mg by inhalation every 12 hr

General Information

Common Usage

Pseudomonal and other gram negative infections.

Inhaled form used in cystic fibrosis.

Drug Monitoring

Lab

  • 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

Note: Trough level is 0-60 min before a dose (usually pre-4th), and peak is 30-60 min 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.

Clinical

  • Baseline and periodic hearing and vestibular function testing (particularly in those receiving prolonged therapy)

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: 3 hours

Urine penetration: Therapeutic

Lung penetration: Therapeutic

CSF penetration: Poor

Biliary penetration: Moderate