Aim For several drugs available as licensed liquids, multiple concentrations exist. Four different propranolol concentrations are available: 1 mg/mL, 2 mg/mL, 8 mg/mL and 10 mg/mL.¹ Existence of multiple concentrations increases the chance of dosing errors. The Neonatal and Paediatric Pharmacists Group (NPPG) and the Royal College of Paediatrics and Child Health (RCPCH) recommend standard concentrations for some unlicensed liquid medicines², but no such recommendation exists for drugs available as licensed products. The British National Formulary for Children (BNFC) advocates that propranolol 1 mg/mL be used to manage infantile haemangioma, but no recommendation is made for other indications.¹ This study aimed to characterise the use of the various propranolol liquid concentrations and determine how closely the recommendation to use 1 mg/mL for haemangioma is followed.

Method A Survey Monkey^® questionnaire was created and distributed to NPPG members by email, remaining open for two weeks. Respondents were asked whether the recommendation to use 1 mg/mL for haemangioma is followed in their centres. Where this recommendation was not followed, respondents indicated the alternative concentration used. Use of alternative concentrations for other indications was also probed, plus the rationale for the use of more than one concentration. Centre name was requested to identify duplicate responses, with the plan to subsequently present the data in an anonymised form. Ethical approval was not required.

Results 64 responses were received. Three centres provided duplicate responses; in two of these cases the answers given matched, but in one the answers conflicted. Where the duplicates matched, data was included in the analysis only once for each centre. Where the response conflicted, it was excluded from analysis. Responses from 60 centres were analysed: 57 from the United Kingdom (UK) and 3 from elsewhere. 31 (52%) of centres use 1 mg/mL for treatment of infantile haemangioma, reflecting BNFC recommendations. For those not following the recommendation, 9 used only a 2 mg/mL concentration and 17 used only 10 mg/mL. Two centres used different concentrations according to the dose prescribed; none reported using 8 mg/mL and one non-UK centre reported use of 20 mg/mL. 26 (43%) centres reported using more than one concentration of propranolol liquid. One cited reason included trying to follow both the BNFC recommendation to use 1 mg/mL for haemangioma whilst also trying to meet regional cardiac centre requests to use 10 mg/mL. Deviating from the recommended 1 mg/mL for haemangioma due to patients being unable to tolerate large dose volumes was raised, as was excipient load in some 1 mg/mL products. Respondents expressed a desire to standardise to a single concentration, though the recommendation to use 1 mg/mL for haemangioma was highlighted as a barrier. Treatment of both adults and children within individual institutions was also considered a complicating factor.

Conclusions The recommendation to use 1 mg/mL when treating haemangioma is not followed in just under 50% of centres. Over 40% of centres reported having more than one concentration of propranolol in use. There is a desire to adopt a single standardised concentration for all indications, although there are a number of potential barriers. Further work is needed to establish the best approach for standardisation.

References

1. Propranolol. Joint Formulary Committee. British National Formulary for Children (Online). London: BMJ Group and Pharmaceutical Press. Available from: http://www.medicinescomplete.com [Accessed June 2022].

2. Using Standardised Concentrations of Liquid Medicines in Children. Neonatal and Paediatric Pharmacists Group and Royal College of Paediatrics and Child Health. Available from http://nppg.org.uk/standardised-strengths-of-liquid-medicines-for-children/ [Accessed June 2022].