Objective To determine the type and frequency of manipulations of drug dosage forms required to administer smaller doses for children and the drugs involved.

Methods An experienced paediatric clinical pharmacist estimated the requirement to manipulate a medicine to achieve accurate dose administration from prescription data in all neonatal and paediatric inpatients collected over 5-day periods and information on drug dosage form availability in a regional children's hospital (RCH) and regional paediatric intensive care unit (RPICU), a regional neonatal intensive care unit (RNICU) and paediatric and neonatal wards of a district general hospital (DGH) using paper-based prescribing systems. Doses were expressed by weight. Ward stock supply with some intravenous drugs ready-to-administer was provided. The main outcome measures were the estimated requirement for dosage form manipulation, nature of the manipulation and drug name.

Results Of 5375 evaluated drug administrations, 542 (10.1%) were judged to require manipulation or measurement of a small volume (<0.2 ml). The most frequent manipulation was measurement of oral dose in volumes of 0.1 to <0.2 ml in the DGH. Requirement to measure doses of <0.1 ml (oral and intravenous) accounted for 25.2% of all manipulations, with the need to measure intravenous doses of <0.1 ml being most frequent in the RNICU and RPICU (60.4% and 31.9% of manipulations, respectively). Hydrocortisone was the drug most frequently judged to require manipulation with both measurement of small volumes for intravenous injection (RPICU and RNICU) and segmentation of tablets (RCH).

Conclusions Manipulation of medicines (including measurement of very small volumes) to provide accurate smaller doses for children is common in the hospital setting.