Variations in captopril formulations used to treat children with heart failure: a survey in the United Kingdom.

Background and objective: Different liquid formulations of a drug prepared for use in children cannot be assumed to have therapeutic equivalence. The objective of this study was to ascertain the interhospital constancy of unlicensed liquid captopril formulations used to treat children with heart failure in the UK. Design: A questionnaire-based telephone survey. Setting: 13 tertiary paediatric cardiac centres in the UK and 13 large hospitals referring patients to these centres. Participants: The study included pharmacists responsible for providing the pharmaceutical input to children with congenital heart disease or a pharmacist designated to cover paediatric services. Technical staff employed by ‘‘specials’’ manufacturers also participated. Results: Four hospitals dispensed captopril tablets for crushing and dissolving in water before administration; the remaining 22 used nine different liquid formulations of captopril. Only three cardiac centres and their referring hospitals were found to be using the same liquid captopril formulations; 10 centres and their referring hospitals were using completely different captopril formulations. Conclusions: This survey shows that paediatric cardiac centres and their referring hospitals use a variety of unlicensed liquid captopril formulations interchangeably. This degree of inconsistency raises issues about optimal captopril dosing and potential toxicity, such that its use may influence paediatric cardiac surgical and interventional outcomes.