What is the recommended dose and administration frequency of amikacin (every 12 or 24 hours)?

Amikacin Dosing and Administration Frequency

The recommended dose of amikacin for adults with normal renal function is 15 mg/kg/day (maximum 1.0 g/day) administered as a single daily dose, with dose reduction to 10 mg/kg/day (maximum 750 mg) for patients over 59 years of age. 1

Standard Dosing for Adults with Normal Renal Function

• Single daily dosing (preferred): 15 mg/kg/day IV or IM as a single daily dose 2, 1

  • Maximum: 1.0 g/day
  • For patients >59 years: 10 mg/kg/day (maximum 750 mg)

• Alternative dosing regimens (per FDA label) 3:

  • 7.5 mg/kg every 12 hours (divided twice daily)
  • 5 mg/kg every 8 hours (divided three times daily)

Pediatric Dosing

• Children: 15-30 mg/kg/day as a single daily dose 2
• Neonates: Dosing varies based on weight and postnatal age 1

Dosing in Renal Impairment

Amikacin requires dose adjustment in renal impairment due to increased risk of ototoxicity and nephrotoxicity 2, 3:

1. Maintain dose but extend interval:

   • Keep dose at 12-15 mg/kg
   • Reduce frequency to 2-3 times weekly
   • If serum creatinine is available but creatinine clearance is not: multiply serum creatinine by 9 to determine dosing interval in hours 3

2. Reduce dose but maintain interval:

   • Start with normal loading dose (7.5 mg/kg)
   • Reduce maintenance dose proportional to reduction in creatinine clearance 3

Monitoring

Therapeutic drug monitoring is essential for amikacin therapy 1, 3:

• Target levels:

  • Peak (30-90 min after injection): 25-35 μg/mL
  • Trough (just before next dose): <5-10 μg/mL
  • Avoid peak levels >35 μg/mL and trough levels >10 μg/mL

• Baseline assessment:

  • Audiogram
  • Vestibular testing
  • Romberg testing
  • Serum creatinine

• Ongoing monitoring:

  • Monthly renal function
  • Monthly assessment of auditory/vestibular symptoms
  • Repeat audiogram if eighth nerve toxicity symptoms develop

Clinical Pearls and Pitfalls

• Single daily dosing advantages: Higher peak concentrations enhance concentration-dependent bactericidal effect while allowing longer drug-free periods to reduce toxicity 2, 1

• Common pitfalls:

  • Underdosing in critically ill patients: Standard doses may be insufficient to reach therapeutic levels 4
  • Failure to adjust for renal impairment: Can lead to accumulation and toxicity 5
  • Inadequate monitoring: Failure to measure drug levels can lead to subtherapeutic treatment or toxicity 3

• Special populations:

  • Burn patients may require more frequent dosing (e.g., 7.5 mg/kg every 6 hours) due to altered pharmacokinetics 6
  • Patients with severe sepsis may benefit from higher loading doses (25-30 mg/kg) to achieve therapeutic targets 4

Administration

• Amikacin can be administered intramuscularly or intravenously
• IV administration should be infused over 30-60 minutes 1, 3
• For patients on dialysis, administer after dialysis session 2

The evidence strongly supports once-daily dosing of amikacin as the preferred regimen for most patients with normal renal function, with appropriate dose adjustments for special populations and those with renal impairment.