Gentamicin

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General

  • Type: Aminoglycosides
  • Dosage Forms: IM; IV
  • Common Trade Names: Genticyn, Garamycin, Gentak

Adult Dosing

  • All: If obese, use Adjusted Weight = IBW + 0.4 x (ABW - IBW)
  • All: Adjust repeat dosing based on levels

General

  • Extended Interval
    • 5-7mg/kg IV q24h
    • First Dose: 5-7mg/kg IV
  • Conventional
    • 1-1.7mg/kg IM/IV q8h

Uncomplicated Gonococcal

  • 240mg IM x 1

Severe PID

  • 1.5mg/kg IM/IV q8h
    • Start 2mg/kg IM/IV x 1
  • Alt: 3-5mg/kg IM/IV q24h
  • Info: Give with clindamycin

Pediatric Dosing

  • All: adjust repeat dosing based on levels

General (<8 Days Old)

  • First Dose All: 2.5mg/kg IV/IM x1
  • <28 weeks gestation
    • 2.5mg/kg IV/IM q24h
    • Alt: 5mg/kg IV/IM q48h
  • 28-29 weeks gestation
    • 2.5mg/kg IV/IM q18h
    • Alt: 5mg/kg IV/IM q48h
  • 30-33 weeks gestation
    • 2.5mg/kg IV/IM q18h
    • Alt 1: 3.5mg/kg IV/IM q24hr
    • Alt 2: 4.5mg/kg IV/IM q36-48h
  • 34 weeks gestation
    • 2.5mg/kg IV/IM q18h
    • Alt 1: 3.5mg/kg IV/IM q24hr
    • Alt 2: 4mg/kg IV/IM q24-36h
  • 35-36 weeks gestation
    • 2.5mg/kg IV/IM q 12h
    • Alt 1: 3.5mg/kg IV/IM q24
    • Alt 2: 4mg/kg IV/IM q24-36h
  • Full Term
    • 2.5mg/kg IV/IM q12h
    • Alt: 4mg/kg IV/IM q24h

General (8 Days - 1 Month)

  • First Dose All: 2.5mg/kg IV/IM x1
  • <30 weeks gestation
    • 2.5mg/kg IV/IM q18h
    • Alt: 4mg/kg IV/IM q24-36h
  • 30-33 weeks gestation
    • 2.5mg/kg IV/IM q12h
    • Alt: 4mg/kg IV/IM q24
  • 34 weeks gestation
    • 2.5mg/kg IV/IM q12h
    • Alt: 4mg/kg IV/IM q18h
  • 35-36 weeks gestation
    • 2.5mg/kg IV/IM q8h
    • Alt: 4mg/kg IV/IM q12h
  • Full term
    • 2.5mg/kg IV/IM q8h
    • Alt: 4mg/kg IV/IM q24h

General (1 Month -6 Months)

  • 2.5mg/kg IV/IM q8h
  • Alt: 6.5mg/kg IV/IM q24h

General (>6 Months)

  • 2.5mg/kg IV/IM
  • Alt: 6.5-7.5mg/kg IV/IM q24h
  • Use IBW if >2yo

Special Populations

  • Pregnancy Rating: D
  • Lactation: Probably safe
  • Renal Dosing
    • Adult
      • Conventional interval dosing
        • CrCl 10-50: give q12-48h
        • CrCl <10: give q48-72h
        • Hemodialysis: give 1-1.7mg/kg after dialysis
      • Extended interval dosing
      • CrCl 30-60: increase dosing interval based on levels
      • CrCl <30: avoid use
    • Pediatric
      • Conventional interval dosing
        • CrCl 30-50: give q12-48h
        • CrCl: 10-29: Give q18-24h
        • CrCl <10: give q48-72h
        • Hemodialysis/peritoneal dialysis: give 2mg/kg after dialysis
      • Extended interval dosing
      • CrCl 30-60: increase dosing interval based on levels
      • CrCl <30: avoid use
  • Hepatic Dosing (Adult & Pediatric)
    • Not defined

Contraindications

  • Allergy to class/drug

Adverse Reactions

Serious

  • Ototoxicity[1]
  • Nephrotoxicity
  • Prolongation of neuromuscular blockers

Common

  • Nausea/vomiting
  • Irritation at injection site

Pharmacology

  • Half-life:2-3 hours
  • Metabolism:
  • Excretion: Urine excretion
  • Mechanism of Action: Binds to 30S and 50S ribosomal subunits, disrupting mRNA translation and interfering with bacterial protein synthesis[2]

Antibiotic Sensitivities[3]

Group Organism Sensitivity
Gram Positive Strep. Group A, B, C, G R
Strep. Pneumoniae R
Viridans strep X1
Strep. anginosus gp X1
Enterococcus faecalis S
Enterococcus faecium S
MSSA S
MRSA R
CA-MRSA X1
Staph. Epidermidis I
C. jeikeium R
L. monocytogenes S
Gram Negatives N. gonorrhoeae R
N. meningitidis R
Moraxella catarrhalis S
H. influenzae S
E. coli S
Klebsiella sp S
E. coli/Klebsiella ESBL+ S
E coli/Klebsiella KPC+ R
Enterobacter sp, AmpC neg S
Enterobacter sp, AmpC pos S
Serratia sp X1
Serratia marcescens S
Salmonella sp X1
Shigella sp S
Proteus mirabilis X1
Proteus vulgaris S
Providencia sp. X1
Morganella sp. X1
Citrobacter freundii X1
Citrobacter diversus X1
Citrobacter sp. X1
Aeromonas sp X1
Acinetobacter sp. R
Pseudomonas aeruginosa S
Burkholderia cepacia R
Stenotrophomonas maltophilia R
Yersinia enterocolitica S
Francisella tularensis S
Brucella sp. S+'
Legionella sp. X1
Pasteurella multocida X1
Haemophilus ducreyi X1
Vibrio vulnificus I
Misc Chlamydophila sp R
Mycoplasm pneumoniae R
Rickettsia sp R
Mycobacterium avium X1
Anaerobes Actinomyces R
Bacteroides fragilis R
Prevotella melaninogenica R
Clostridium difficile R
Clostridium (not difficile) X1
Fusobacterium necrophorum R
Peptostreptococcus sp. R

Key

  • 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

See Also

References

  1. https://www.drugs.com/monograph/gentamicin-systemic.html
  2. Chaves BJ, Tadi P. Gentamicin. [Updated 2022 May 1]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK557550/
  3. Sanford Guide to Antimicrobial Therapy 2014