Accuracy and Stability of Enteral Paediatric Nifedipine Doses Roshni Kankali Dr Daniel Kirby Astrid Gerrard

What We Already Know Lack of suitable paediatric dosage formulations Manipulation of solid and liquid dosage forms – unlicensed use Nifedipine susceptible to photodegradation and hydrolysis Variation in clinical response to administered doses

Aim To determine the reproducibility and accuracy of methods used by nursing staff to prepare fractional doses of enteral nifedipine in liquid form in clinical practice and make recommendations to standardise this procedure.

Phase 1 Single tertiary hospital - 3 wards Nurse observation Informal nurse interviews Questionnaire on manipulation methods Phase 2 Dose uniformity of simple manipulations Laboratory based re-production of identified manipulation methods Target doses 5 mg, 1 mg, 0.5 mg Limited short term stability studies

Even simple manipulation leads to significant variation in dose.

Tablet and liquid suspensions destabilise to less than 90% of intended concentration within minutes.

Tablet Manipulation Split 10mg tablet in half (guillotine tablet splitter) Crush 10mg tablet (screw top tablet crusher) Resuspend in beaker Technique 1 Resuspend within the syringe Technique 2 Resuspend within the pill crusher Technique 3 Resuspend in beaker Technique 4

Dispersion of halved tablet in syringe (technique 2) achieved reproducible results with 93-95% of intended dose for 5 mg and 1 mg doses but marked overdoses for 0.5 mg doses (143 – 144%) 5 mg dose 1 mg dose 0.5 mg dose

Drop Manipulation Measure required nifedipine liquid using oral syringe Instil required number of nifedipine drops Use separate syringes Mix in beaker Technique 1 Dilute within the same syringe Technique 2 … into beaker and dilute with water Technique 3 … directly into patients mouth * Technique not used for 0.5mg dose Technique 4

No single technique currently used by nursing staff achieved accurate reproducible results for all doses. 5 mg dose 1 mg dose 0.5 mg dose

Limitations Small project Single operator Laboratory-based

Conclusions Wide variation of intended doses ? Impact on clinical outcomes Need child-friendly formulations Review drug choice – round doses Standardise manipulation methods ? monographs