Dosage in children

Children's doses in the BNF are stated in the individual drug entries as far as possible, except where paediatric use is not recommended, information is not available, or there are special hazards.

Doses are generally based on body-weight (in kilograms) or the following age ranges: first month (neonate) up to 1 year (infant) 1-5 years 6-12 years

Unless the age is specified, the term 'child' in the BNF includes persons aged 12 years and younger.

Prescription writing Prescriptions should be written according to the guidelines in Prescription Writing (p. 5) Inclusion of age is a legal requirement in the case of prescription-only medicines for children under 12 years of age, but it is preferable to state the age for all prescriptions for children.

It is particularly important to state the strengths of capsules or tablets. Although liquid preparations are particularly suitable for children, they may contain sugar which encourages dental decay. Sugar-free medicines are preferred for long-term treatment.

Many children are able to swallow tablets or capsules and may prefer a solid dose form; involving the child and parents in choosing the formulation is helpful. When a prescription for a liquid oral preparation is written and the dose ordered is smaller than 5 mL an oral syringe will be supplied (for details, see p. 2).

Dose calculation Many children's doses are standardised by weight (and therefore require multiplying by the body-weight in kilograms to determine the child's dose); occasionally, the doses have been standardised by body surface area (in m2). These methods should be used rather than attempting to calculate a child's dose on the basis of doses used in adults.

For most drugs the adult maximum dose should not be exceeded. For example if the dose is stated as 8mg/kg (max. 300 mg), a child weighing 10 kg should receive 80 mg but a child weighing 40 kg should receive 300 mg (rather than 320 mg).

Young children may require a higher dose per kilogram than adults because of their higher metabolic rates. Other problems need to be considered. For example, calculation by body-weight in the overweight child may result in much higher doses being administered than necessary; in such cases, dose should be calculated from an ideal weight, related to height and age (see inside back cover).

Body surface area (BSA) estimates are sometimes preferable to body-weight for calculation of paediatric doses since many physiological phenomena correlate better with body surface area. Body surface area can be estimated from weight. For more information, refer to BNFfor Children.

Where the dose for children is not stated, prescribers should consult BNFfor Children or seek advice from a medicines information centre.

ldrDose frequency Antibacterials are generally given at regular intervals throughout the day. Some flexibility should be allowed in children to avoid waking them during the night. For example, the night-time dose may to be given at the child's bedtime.

ibiWhere new or potentially toxic drugs are used, the crmanufacturers' recommended doses should be carefully a followed.

Was this article helpful?

0 0

Post a comment