Introduction
In recent years, governments and researchers in different countries have spent a great deal of resources on studying medication errors and have raised concerns about medical errors. Much of this research has been conducted in the adult population. In paediatric medicine, drug doses are usually calculated individually based on the patient's age, weight and surface area leading to increased opportunities for error and relatively high risk of dosing errors. We therefore conducted a systematic review to establish the strength of the evidence that dosage errors were a significant problem in paediatric practice.

Method
A systemic search of studies that investigated the incidence and nature of dosing errors in paediatrics was performed using different databases. A number of keywords were used in this search, which was limited to the English language. The search produced 165 references; 118 were excluded and 47 deemed relevant to the search. The reference lists of the selected papers were also reviewed to identify other relevant studies; only one additional paper was identified.

Results
Sixteen of 48 studies specifically investigated the incidence of medication errors in children and also reported the incidence of dosing errors. It was found that in 11 of the 16 studies, dosing errors were the most common type of medication error in children; while in three of the remaining studies, they were the second most common type. The incidence of dosing errors varies; for example it ranges from 0.03 per 100 admissions in the UK (1) to 2 per 100 admissions in the US (2) using spontaneous reporting.

Discussion
There was great variation in the dosing error rates reported in the literature. This variation was likely to be due to the differences in methodologies employed. The evidence so far suggests that dosing errors are the most common type of paediatric medication error regardless of the methodologies or definitions employed. In addition, the information available shows that dose errors are not uncommon and 10-fold or greater overdose caused by calculation errors have led to serious consequences. Using the most conservative of our estimates the projected number of paediatric dosing error cases would be 50,000 in England alone in the 2001-2002 financial year.

Conclusion
The limited literature on paediatric medication errors suggests that dosing errors are probably the most common medication errors in this population and there is an urgent need to research appropriate interventions to reduce this type of error.

Reference
1. Ross LM, Wallace J, Paton JY. Medication errors in a paediatric teaching hospital in the
UK: five years operational experience. Archives of Disease in Childhood. 2000; 83:492-7.
2. Raju TN, Kecskes S, Thornton JP, Perry M, Feldman S. Medication errors in neonatal and
paediatric intensive-care units. Lancet. 1989; 2:374-6.