Prepared by Dr Mariam Buksh, Amy Chan, Brenda Hughes &
Elizabeth Oliphant
Reviewed by Dr Andrew Liley, Clinical Leader, Acute Pain Service, Starship Children’s Health, Auckland City Hospital
February 2011
Administration Newborn Drug Protocol Index Newborn Services Home Page

Dose and Administration

Postmenstrual Age
Maximum Dose
<32/40 7.5 8 22.5 mg/kg/day
32/40 7.5 6 30 mg/kg/day


Intravenous Paracetamol use should be reviewed daily on ward rounds.

It is recommended to use a suitable oral or rectal analgesic treatment as soon as practicable.



Clinical Pharmacology

Paracetamol has analgesic and antipyretic actions but only weak anti-inflammatory properties. It inhibits prostaglandin biosynthesis in conditions associated with low levels of cellular peroxides (pain, fever).

Due to metabolic immaturity, neonatal clearance of paracetamol is different from adults. Sulphate conjugation is well developed in a neonate and is the major metabolic pathway for paracetamol clearance. Glucuronidation clearance is not well developed and plays a minor role in paracetamol clearance in neonates. With maturation these clearance pathways for paracetamol change. The usual adult ratio of 2:1 glucuronide to sulphate conjugates of paracetamol is achieved by 12 years of age.

The enzyme systems P450 CYP2E1, 1A2, 3A4 are responsible for forming paracetamol toxic metabolites. Despite a low activity of P450 CYP 2E1 in neonates, toxic metabolites can still be formed.

In neonates, the half life of intravenous paracetamol is approximately 3.5 hours.

Possible Adverse Effects

Special Considerations