Tobramycin

C. diff Risk

Low

Oral Bioavailability

NA

Approximate Cost

Dosing

Multiple Daily Dose (MDD) 2mg/kg IV load then 1.7mg/kg IV q8h Once Daily (OD) 5-7mg/kg IV q24h IV

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 MDD: Target Peak 4-10 ug/mL, Trough 1-2 ug/mL.

For OD: Target Trough <1 ug/mL

NB: trough level is 0-60min 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)- less common with once daily dosing; greater toxicity with longer duration and supratherapeutic trough levels; avoid concomitant nephrotoxins

Vestibulocochlear toxicity (irreversible)- require audiology testing if prolonged use

Can exacerbate neuromuscular blockade- e.g. contraindicated in patients with myasthenia gravis.

Major Interactions

Increased nephrotoxicity with: 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 to report any symptoms

Contraindicated in patients with myasthenia gravis

Pharmacology

Antimicrobial class: Aminoglycoside

Pregnancy category: D

Average serum half life: 3.0

Biliary penetration: Moderate

CSF penetration: Poor

Lung penetration: Therapeutic

Urine penetration: Therapeutic