Common errors when prescribing simple analgesics to children
The most likely error that occurs when analgesics are prescribed is overdose.5 This is of particular concern
as most of these medicines have a high likelihood of serious adverse events. One of the reasons that analgesics are associated
with dosing error is that they are often prescribed “prn” which increases the potential for overdose.
Paracetamol is the preferred first-line analgesic for children for fever and mild to moderate pain. It has few adverse
effects when dosed correctly, however serious, and sometimes even fatal, liver toxicity can occur with acute and chronic
The weight-based dose for paracetamol in children is generally 10�15 mg/kg, every four to six hours (maximum of four
doses in 24 hours).11,12
The BNF for children states:11
Paracetamol 120 mg/5 mL
- Infants 1�3 months: 30�60 mg, eight hourly (maximum 60 mg/kg/day in divided doses)
- Infants 3�12 months: 60�120 mg every 4�6 hours (maximum 4 doses/24 hours)
- Children 1�5 years: 120�250 mg every 4�6 hours (maximum 4 doses/24 hours)
Paracetamol 250 mg/5 mL
- Children 6�12 years: 250�500 mg every 4�6 hours (maximum 4 doses/24 hours)
Lack of awareness of the strengths of different paediatric formulations e.g. 120 mg/5 mL or 250 mg/5 mL, and use of
more than one preparation containing paracetamol, may lead to dosage errors and toxicity.
Error example: A mother is used to giving her five-year-old child 10 mL of paracetamol 120 mg/5 mL.
When her child is then prescribed a higher strength formulation (i.e. 250 mg/5 mL), the change in dosing instructions
was not carefully explained to her, she does not read the label and gives the usual 10 mL.
Error example: A child presents to the practice with symptoms of a respiratory infection. The GP diagnoses
viral upper respiratory infection and explains that antibiotics are not necessary and that cough and cold preparations
are not recommended. The GP writes a prescription for paracetamol 120 mg/5 mL, 5 mL, four times per day.
The mother returns with the child the next day, concerned because he is lethargic and sweaty. She reveals that she
gave the child the paracetamol as instructed, but also had some “Pamol” at home and gave that too. In addition,
as she was advised against giving “cough mixture” she made the child a warm “Lemsip” drink. The
mother was not aware that all of these products contained paracetamol.
Over the past 24 hours the child had four 5 mL doses of paracetamol 120 mg/5 mL, four 5 mL doses of Pamol (paracetamol
250 mg/5 mL) and one sachet of Lemsip (paracetamol 500 mg). In total this is 1980 mg of paracetamol, giving a dose of
198 mg/kg in the 10 kg child.
The child was referred to secondary care with suspected paracetamol toxicity. Although the mother herself made many
errors, this example highlights the importance of carefully explaining medicines to parents, including generic and trade
names they might know them by. Also instruct parents how to read labels of over-the-counter medicine preparations and
know what medicines they contain.
Ibuprofen is an alternative to paracetamol for the management of pain (e.g. musculoskeletal pain) and fever. It is
associated with an increased risk of gastrointestinal bleeding. There have also been reports of renal toxicity and aspirin-like
sensitivity reactions.14 Ibuprofen should not be used if the child is dehydrated or has acute renal failure.
All NSAIDs have the potential to worsen asthma, either acutely or as a gradual worsening of symptoms.11 Therefore
children with asthma should preferably use paracetamol.
Always use the lowest effective dose, for the shortest possible duration, and preferably administer after
food. For infants and children the usual oral dose is 20 mg/kg/day, in divided doses (if over 7 kg and a severe condition,
this can be up to 30 mg/kg/day). In children weighing less than 30 kg, the total daily dose should not exceed 500 mg.11
The BNF for children states:11
Ibuprofen 100 mg/5 mL:
- Infants 1�6 months: 5 mg/kg, three to four times daily
- Infants 6�12 months 50 mg, three times daily
- Children 1�2 years 50 mg, three to four times daily
- Children 2�7 years 100 mg, three to four times daily
- Children 7�18 years 200 mg, three to four times daily
Error example: A 10-year old child is prescribed 200 mg ibuprofen (100 mg/5 mL), with the instruction “use
as required”. The doctor is running late and does not weigh the child. The child is of lean build and weighs 27
kg. The child’s parents give her five doses of medicine during the day (every four hours), equalling a total dose
of 1000 mg.
- The doctor did not weigh the child for a more accurate dose
- The doctor did not provide clear dose instructions, with dosing intervals and maximum daily dose
- The pharmacist did not double-check the dose and explain the dosing instructions to the parents
- The maximum recommended daily dose of 500 mg in a child weighing less than 30 kg was exceeded.
Aspirin should not be used in children aged less than 12 years, although some countries, including the UK, do not recommend
use under age 16 years. Although it is a well-documented analgesic, anti-inflammatory and antipyretic, aspirin is associated
with Reye’s syndrome in children.14
Given that other effective analgesics are available, it is usually not necessary to prescribe aspirin to a child of
any age for pain relief in general practice.
See Correspondence “Aspirin
in children”, BPJ 17 (Oct, 2008) and BPJ 27 Quiz Feedback “What
is Reye’s syndrome” for further information.