Table 1

Paediatric age groups and body weights used for assessing dose adaptability*

Child groupAge†Body weight‡
Neonates0–27 days0.5 kg, preterm; 3.5 kg, term; up to 4.5 kg at 27§ days
Infants28 days to 11 months4.5–10 kg
Toddlers1–2 years10¶–14 kg
Young children3–5 years14–18 kg
Older children to6–11 years≈20**–39 kg
  • The upper and lower body weights limits in table 1 were used to calculate the required dose range needed for each age group.

  • It was assumed that dose rounding (0%–15%) would be employed in practice, depending on the drug’s therapeutic index and doses in the MFc were adjusted accordingly to see if they would match the formulation strength listed in the EMLc.

  • Doses for medicines known to have a narrow therapeutic index (eg, digoxin, levothyroxine, carbamazepine, methotrexate and warfarin) were not rounded.

  • *Recently, the use of age bands for clinical trials and for drug dosing has been challenged38 since relevant physiological development is a continuum that does not always match discrete age bands. Most research has related ability to manage different formulations to age. Hence, we grouped children into age bands for this study report.

  • †Completed days, months and years.

  • ‡Source: BNFc (2011–2012).19

  • §3.5 kg only (BNFc 2019–2020).

  • ¶9 kg (BNFc 2019-2020)

  • **18 kg (BNFc 2019–2020).20

  • BNFc, British National Formulary for Children; EMLc, Essential Medicine List for children; MFc, Model Formulary for children.