• Type: Aminoglycoside
  • Dosage Forms: IV
  • Common Trade Names: Tobrex

Adult Dosing

Infection, bacterial

  • 1-1.7 mg/kg IM/IV q8h
  • For extended interval dosing:
    • 5-7 mg/kg IV q24h

Pneumonia, Hospital-acquired

  • 5-7 mg/kg IV q24h x7 days

Respiratory infections, Cystic fibrosis pts

  • 10-12 mg/kg IV q24h
  • Alt: 2.5-3.5 mg/kg IV q8h

Endocarditis, Gram positive synergy

  • 3 mg/kg IV q24h for at least 2 weeks as part of multi-drug regimen

Pediatric Dosing

Infection, bacterial

  • <8 days old
    • 2 mg/kg IV/IM q12h
  • >8 days old
    • 2-2.5 mg/kg IV/IM q8h

Respiratory infections, Cystic fibrosis pts

  • >1 mo
    • 10-12 mg/kg IV q24h

Febrile neutropenia, post-stem cell transplant

  • <5 yo
    • 9 mg/kg IV q 24h
  • 5-11 yo
    • 8 mg/kg IV q24h
  • 12+ yo
    • 7 mg/kg IV q24h

Endocarditis, Gram positive synergy

  • 3-6 mg/kg IV divided q8h as part of multi-drug regimen

Special Populations

  • Pregnancy Rating: C
  • Lactation: May use, no known risk based on drug properties
  • Renal Dosing
    • Adult
      • CrCl 50-70: Give q8-24h
      • CrCl 10-50: Give q24-48h
      • CrCl <10: Give q48-72h
      • HD: Give 50% usual dose after dialysis
      • PD: Give supplement
    • Pediatric
      • CrCl 30-50: Give q12-18h
      • CrCl 10-29: Give q18-24h
      • CrCl <10: Give q48-72h
      • HD/PD: 2 mg/kg x1 then adjust dose based on serum
  • Hepatic Dosing
    • Adult
      • Not defined
    • Pediatric
      • Not defined


  • Allergy to class/drug
  • Caution:
    • Hypersensitivity to sulfites
    • Renal Impairment
    • Dehydration
    • Concurrent nephrotoxic/ototoxic agent
    • Impaired auditory/vestibular fxn
    • Neuromuscular dz
    • Prolonged use

Adverse Reactions


  • Ototoxicity, auditory or vestibular
  • Nephrotoxicity, Neurotoxicity
  • Neuromuscular blockaed
  • Superinfection
  • C. Diff associated diarrhea
  • Anaphylaxis
  • Hypersensitivity rxn
  • Exfoliative Dermatitis
  • Toxic epidermal necrolysis, Stevens-Johnson Syndrome
  • Erythema multiforme



  • Half-life: 2h
  • Metabolism: Minimal to none
  • Excretion: Renal (100% unchanged)
  • Mechanism of Action: Binds to bacterial 30S ribosomal subunit, inhibiting protein synthesis

Antibiotic Sensitivities[1]

Group Organism Sensitivity
Gram PositiveStrep. Group A, B, C, GR
Strep. PneumoniaeR
Viridans strepX1
Strep. anginosus gpX1
Enterococcus faecalisS
Enterococcus faeciumR
Staph. EpidermidisI
C. jeikeiumR
L. monocytogenesS
Gram NegativesN. gonorrhoeaeR
N. meningitidisR
Moraxella catarrhalisS
H. influenzaeS
E. coliS
Klebsiella spS
E. coli/Klebsiella ESBL+S
E coli/Klebsiella KPC+R
Enterobacter sp, AmpC negS
Enterobacter sp, AmpC posS
Serratia spX1
Serratia marcescensS
Salmonella spX1
Shigella spS
Proteus mirabilisX1
Proteus vulgarisS
Providencia sp.X1
Morganella sp.X1
Citrobacter freundiiX1
Citrobacter diversusX1
Citrobacter sp.X1
Aeromonas spX1
Acinetobacter sp.R
Pseudomonas aeruginosaS
Burkholderia cepaciaR
Stenotrophomonas maltophiliaR
Yersinia enterocoliticaS
Francisella tularensisS
Brucella sp.S+'
Legionella sp.X1
Pasteurella multocidaX1
Haemophilus ducreyiX1
Vibrio vulnificusI
MiscChlamydophila spR
Mycoplasm pneumoniaeR
Rickettsia spR
Mycobacterium aviumX1
Bacteroides fragilisR
Prevotella melaninogenicaR
Clostridium difficileR
Clostridium (not difficile)X1
Fusobacterium necrophorumR
Peptostreptococcus sp.R


  • S susceptible/sensitive (usually)
  • I intermediate (variably susceptible/resistant)
  • R resistant (or not effective clinically)
  • S+ synergistic with cell wall antibiotics
  • U sensitive for UTI only (non systemic infection)
  • X1 no data
  • X2 active in vitro, but not used clinically
  • X3 active in vitro, but not clinically effective for Group A strep pharyngitis or infections due to E. faecalis
  • X4 active in vitro, but not clinically effective for strep pneumonia


  1. Sanford Guide to Antimicrobial Therapy 2014
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