Aim A previous study identified that prescribed doses of liquid medicines could not always be measured using a single syringe.¹ Our study aimed to identify whether electronic prescribing improves this and if so how different the prescribed dose would be compared to the BNFC/local dosage recommendations.

Method Liquid and parenteral medicine prescriptions prescribed using paper drug charts, with doses calculated manually, were reviewed on neonatal and paediatric wards during 2 days in July 2014. Electronic prescribing (Epic) was introduced in October 2014 with study observations repeated in April 2016. Patient weight, dose, strength and volume administered were recorded, with analysis of whether doses could be measured using a single syringe. Prescribed doses were compared with the exact calculated BNFC/local dose.

Results 381 liquid medicine doses were reviewed pre-electronic prescribing, and included 75 formulations. 99 (26%) doses were immeasurable. Of these, 42 (42.4%) doses would have been administered with less than 1% difference to the prescribed dose, 31 (31.3%) between 1%–2% difference and 26 (26.2%) between 2%–10% difference.

134 (35.2%) doses were calculated and prescribed exactly using BNFC/local recommendations. 139 (36.5%) doses were adjusted and prescribed with less than 2% difference to the exact calculated dose, 70 (18.4%) between 2%–5% difference and 38 (10%) with >5% difference.

365 liquid medicine doses were reviewed following electronic prescribing implementation, and included 105 formulations. 80 (21.9%) doses were immeasurable. Of these, 35 (43.8%) doses would have been administered with less than a 1% difference to the prescribed dose, 16 (20%) between 1%–2% difference and 29 (36.3%) between 2%–10% difference.

Following introduction of electronic prescribing 166 (45.5%) doses were calculated and prescribed exactly using BNFC/local recommendations. 140 (38.3%) doses were adjusted and prescribed with less than 2% difference to the exact calculated dose, 34 (9.3%) between 2%–5% difference and 25 (6.8%) with >5% difference.

Conclusion There was a small improvement in numbers of measurable doses prescribed using electronic prescribing, with an improvement in the final calculation of prescribed doses compared with BNFC/local doses. Although more doses were measurable using electronic prescribing, there was also an increase in the number of doses with >2% difference between the prescribed and administered dose. The World Health Organisation provide guidance on dose rounding and if prescribed doses do not correspond to available formulations, then doses may be amended while maintaining safety and efficacy, reviewing the therapeutic index of the medicine and patient characteristics.²

Further work now needs to be undertaken locally to identify specific drugs where the electronic prescribing build needs to be amended to allow measurable dose calculation which is as close as possible to the ideal calculated dose but still provides clinical efficacy.

References

1. Morecroft CW, Gill A, et al. Are prescribed doses of medicine for children measurable?Arch Dis Child2012;97:e1–21.

2. Fiftieth report of the WHO expert committee on specifications for pharmaceutical preparations. WHO technical report series (No 996) 2016.