C. diff Risk


Oral Bioavailability


Approximate Cost



Height Males Females
150.0 cm 50.0 kg 45.5 kg
152.5 cm 52.3 kg 47.8 kg
155.0 cm 54.6 kg 50.1 kg
157.5 cm 56.9 kg 52.4 kg
160.0 cm 59.2 kg 54.7 kg
162.5 cm 61.5 kg 57.0 kg
165.0 cm 63.8 kg 59.3 kg
167.5 cm 66.1 kg 61.6 kg
170.0 cm 68.4 kg 63.9 kg
172.5 cm 70.7 kg 66.2 kg
175.0 cm 73.0 kg 68.5 kg
177.5 cm 75.3 kg 70.8 kg
180.0 cm 77.6 kg 73.1 kg
182.5 cm 79.9 kg 75.4 kg
185.0 cm 82.2 kg 77.7 kg
187.5 cm 84.5 kg 80.0 kg
190.0 cm 86.8 kg 82.3 kg

General Information

Unacceptable Uses

Tobramycin is not indicated for synergy in Gram positive infections

Common Usage

Pseudomonal and other gram negative infections.

Inhaled form used in cystic fibrosis.

Drug Monitoring

Serum creatinine whenever initiating any aminoglycoside.

Creatinine and trough level should be monitored AT LEAST twice weekly; more often if unstable renal function or addition
of nephrotoxic medications.

Order appropriate trough level for dosage regimen used

Once Daily/Extended Interval Dosing
Order 6 hour pre-dose level
Target level: less than 1 mg/L

Multiple Daily Dosing
Order tobramycin trough level (0-60 min before a dose)
Desired result: less than 2 mg/L

Tobramycin Peaks
Are not used in once daily/extended interval regimens

For multiple daily dosing regimens, Peaks not commonly measured but if required are collected 30-60 min after dose infused

Adverse Effects


  •  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


  •  Contrast dye

  •  Vancomycin

Increased ototoxicity

  •  Furosemide

Neuromuscular blockade agents - Respiratory paralysis.

Tablet/Capsule Strengths

Nebules: generic are open benefit
TOBI brand require Special Authorization (CF)

Additional Information

IV Administration
Dilute in 100 mL D5W or NS and administer over 30-60 min. (*60 min for extended interval dosing)

EH Prescribing Restrictions
None (Pharmacist review of therapy)

Community IV Formulary (Metro area

See EH Intranet for Full Aminoglycoside dosing policy:
PHA-124: Aminoglycoside Antibiotic Monitoring (Adult)


Antimicrobial class: Aminoglycoside

Pregnancy category: D

Average serum half life: 3 hours

Urine penetration: Therapeutic

Lung penetration: Therapeutic

CSF penetration: Poor

Biliary penetration: Moderate

Route of Elimination: Renal