Procedure Logs

C3.1 R4(e): Perform & document an aminoglycoside pharmacokinetic interpretation

BG is a 40+4/7 week baby who presented with risk factors for sepsis (mom had fever during labour/delivery, BG had fetal tachycardia, and ongoing meconium staining). BG presented with an elevated temperature (38.4C), tachycardic (HR: 190 bpm), fussy, and an elevated CRP (=72.4). BG was started on ampicillin + gentamicin for neonatal sepsis empiric coverage, blood cultures were taken and gentamicin levels were taken around the 3rd dose. The plan was to continue the gentamicin for 5-7 days based on the clinical signs and symptoms and maternal blood cultures (that were taken at the time of labour and delivery). Gentamicin dose is 8.2 mg IV Q12H (=2.5mg/kg/dose) which is appropriate empirically based on the FH neonatal PDTM dosing guidelines for gentamicin (based on GA and day of life).

  • Levels were taken on Oct 3, pre (taken 30 minutes late) = 1.5 mg/L [aim for <2]
  • Oct 2, post (taken 1.5 hours late) = 5.5 mg/L [aim for 5-10mg/L]


Based on this I wrote the following note in the chart:

Clinical Pharmacist Note re: gentamicin levels:

Patient is receiving gentamicin 8.2 mg IV Q12H. Levels taken on Oct 3 around the 3rd dose (dose given at 22:30):

  • 22:24: 1.5 mg/L [range <2 mg/L], extrapolated min = 1.48 mg/L
  • 0105: 5.5 mg/L [range 5-10mg/L], extrapolated max = 7.4 mg/L
  • Patient t1/2 = 5 h [aim for 3-11.5h]
  • Vd = 0.4 L/kg [aim for 0.35-0.55 L/kg]
  • Creatinine = 54 umol/L, Urine output = 2.36 ml/kg/hour

Suggest no change to gentamicin regimen at this time as all pharmacokinetic values are within normal range. No further levels required at this time.

– Iona Berger, Pharmacy Resident

This was an interesting case to practice as the peak level was taken more than 30 minutes apart from the desired time. This was also an interesting patient to work on, as I relied heavily on the maternal cultures and lab values (the mom was readmitted for sepsis workup) to help guide my decisions for antibiotic therapy.

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