Neonatal dosing

Aciclovir IV

AgeStarting dose
Neonates younger than 34 weeks post menstrual age20mg/kg/dose every 12 hours
Neonates 35 weeks post menstrual age or older20mg/kg/dose every 8 hours

Ampicillin IV (or Amoxycillin IV)

AgePost natal ageStarting dose
Neonates < 29 weeks post menstrual agePostnatal age 0 to 28 days50mg/kg/dose every 12 hours
Neonates < 29 weeks post menstrual agePostnatal age > 28 days50mg/kg/dose every 8 hours
Neonates 30 to 36 weeks post menstrual agePostnatal age 0 to 14 days50mg/kg/dose every 12 hours
Neonates 30 to 36 weeks post menstrual agePostnatal age > 14 days50mg/kg/dose every 8 hours
Neonates 37 to 44 weeks post menstrual agePostnatal age 0 to 7 days
50mg/kg/dose every 12 hours
Neonates 37 to 44 weeks post menstrual agePostnatal age > 7 days50mg/kg/dose every 8 hours
Neonates > 45 weeks post menstrual ageAll50mg/kg/dose every 6 hours

Benzylpenicillin IV

AgePost natal ageStarting dose
Neonates <29 weeks post menstrual agePostnatal age 0 to 28 days60mg/kg/dose every 12 hours
Neonates <29 weeks post menstrual agePostnatal age >28 days60mg/kg/dose every 8 hours
Neonates 30 to 36 weeks post menstrual agePostnatal age 0 to 14 days60mg/kg/dose every 12 hours
Neonates 30 to 36 weeks post menstrual agePostnatal age >14 days60mg/kg/dose every 8 hours
Neonates 37 to 44 weeks post menstrual agePostnatal age 0 to 7 days
60mg/kg/dose every 12 hours
Neonates 37 to 44 weeks post menstrual agePostnatal age > 7 days60mg/kg/dose every 8 hours
Neonates > 45 weeks post menstrual ageALL30-60mg/kg/dose every 6 hours

Cefotaxime IV

Age Starting dose
Neonates <29 weeks post menstrual agePostnatal age 0 to 28 days50mg/kg/dose every 12 hours
Neonates <29 weeks post menstrual agePostnatal age >28 days50mg/kg/dose every 8 hours
Neonates 30 to 36 weeks post menstrual agePostnatal age 0 to 14 days50mg/kg/dose every 12 hours
Neonates 30 to 36 weeks post menstrual agePostnatal age >14 days50mg/kg/dose every 8 hours
Neonates 37 to 44 weeks post menstrual agePostnatal age 0 to 7 days50mg/kg/dose every 12 hours
Neonates 37 to 44 weeks post menstrual agePostnatal age >7 days50mg/kg/dose every 8 hours
Neonates >45 weeks post menstrual ageAll50mg/kg/dose every 6 hours

Flucloxacillin IV

Post menstrual agePost natal ageStarting dose
Term/Premature neonatesPostnatal age 0 to 7 days50mg/kg/dose every 12 hours
Term/Premature neonatesPostnatal age 8 to 20 days50mg/kg/dose every 8 hours
Term/Premature neonatesPostnatal age 21 to 28 days50mg/kg/dose every 6 hours

Gentamicin IV

Age Starting dose
Neonates younger ≤ 29 weeks post menstrual agePostnatal age 0 to 7 days5mg/kg/dose every 48 hours**
Neonates younger ≤ 29 weeks post menstrual agePostnatal age 8 to 28 days4mg/kg/dose every 36 hours**
Neonates younger ≤ 29 weeks post menstrual agePostnatal age 29 days or older4mg/kg/dose every 24 hours**
Neonates 30 to 34 weeks post menstrual agePostnatal age 0 to 7 days
4.5mg/kg/dose every 36 hours**
Neonates 30 to 34 weeks post menstrual agePostnatal age 8 to 28 days4mg/kg/dose every 24 hours**
Neonates 35 weeks post menstrual age or olderAll ages
4mg/kg/dose every 24 hours**

Metronidazole IV

Age Starting dose
Neonates <29 weeks post menstrual agePostnatal age 0 to 28 days7.5mg/kg/dose every 48 hours
Neonates <29 weeks post menstrual agePostnatal age >28 days7.5mg/kg/dose every 36 hours
Neonates 30 to 36 weeks post menstrual agePostnatal age 0 to 14 days7.5mg/kg/dose every 24 hours
Neonates 30 to 36 weeks post menstrual agePostnatal age >14 days7.5mg/kg/dose every 12 hours
Neonates 37 to 44 weeks post menstrual agePostnatal age 0 to 7 days

7.5mg/kg/dose every 24 hours
Neonates 37 to 44 weeks post menstrual agePostnatal age > 7 days7.5mg/kg/dose every 12 hours
Neonates >45 weeks post menstrual ageAll7.5mg/kg/dose every 8 hours

Vancomycin IV

Therapeutic drug monitoring required**

Age Starting dose
Neonates younger ≤ 29 weeks post menstrual agePost natal age 0 to 14 days15mg/kg/dose IV 18 hourly**
Neonates younger ≤ 29 weeks post menstrual agePost natal age >14 days15mg/kg/dose IV 12 hourly**
Neonates >29 to 36 weeks post menstrual agePost natal age 0 to 14 days15mg/kg/dose IV 12 hourly**
Neonates >29 to 36 weeks post menstrual agePost natal age >14 days15mg/kg/dose IV 8 hourly**
Neonates 36 to 44 weeks post menstrual agePost natal age 0 to 7 days15mg/kg/dose IV 12 hourly**
Neonates 36 to 44 weeks post menstrual agePost natal age >7days15mg/kg/dose IV 8 hourly**
Neonates 44 weeks post menstrual age or olderAll ages15mg/kg/dose IV 6 hourly**

Definitions

Postmenstrual age:
The time elapsed between the first day of the last menstrual period and birth (gestational age) plus the time elapsed after birth (postnatal age).

Renal function and drug elimination are most strongly correlated with Postmenstrual Age.