LAUSR

Aim The angiotensin-converting enzyme inhibitor, enalapril, is considered a first-line treatment for chronic heart failure in children. However, there is a lack of an age-appropriate formulation and tablet splitting, although not recommended, is common, in an attempt, to provide suitable doses for paediatric use. An analysis of currently available UK brands explored the accuracy of splitting low-dose tablets of enalapril. Method Four different commercially available enalapril tablets were evaluated: Innovace® enalapril 2.5 mg and 5 mg, (both Organon Pharma UK), generic enalapril 5 mg (Ria Generics Ltd) and generic enalapril 2.5 mg (Dexcel Pharma Ltd). Five tablets from each brand/dose were split manually where possible. For unscored tablets, a sharp knife or metal spatula was used to replicate the home environment. Tablet fragments were weighed. Using high-performance liquid chromatography, the percentage of the theoretical 1.25 mg or 2.5 mg dose contained within the half-tablet fragments was analysed (percentage label claim [%LC]) and the uniformity of dosage units was calculated (acceptance value [AV]), where an AV of ≤15 is considered to meet the acceptance criteria. Results Manual splitting proved relatively easy only with the deep-scoring of the Innovace 5 mg tablets; 0.007 to 0.483 mg of material was lost across the five replicates, the mean%LC (SD) was 97.5% (4.3) and the AV was 11.3. The unscored Innovace 2.5 mg tablets split less easily; 0.113 to 0.627 mg of material was lost, mean%LC (SD) was 99.9% (10.7) and the AV was 25.7. The soft 5 mg Ria Generics tablets split with high variability: 0.609 to 13.488 mg of material was lost, mean%LC (SD) was 96.0% (17.9) and AV was 45.5. Dose variation was also high with 2.5 mg Dexcel tablets, with 1.097 to 13.801 mg of material lost, mean%LC (SD) of 95.9% (11.7) and an AV of 30.7. Conclusion In general, splitting low-dose tablets of enalapril for paediatric use results in inaccurate dosing. Acceptable dosing was only achieved with the scored 5 mg tablets. Accurate doses below 2.5 mg were not achieved. An age-appropriate dosage formulation of enalapril to provide dosing below 2.5 mg is needed.