
Dr Bowen J Fung
Senior Research Advisor
Liquid paracetamol is used for pain relief by most parents and caregivers for tamariki (children). Despite how commonly paracetamol is given to children, parents and caregivers can often forget about the possibility of paracetamol overdose if it isn’t administered carefully.
In fact, in Aotearoa New Zealand, overdoses of paracetamol are the leading cause of acute liver failure in children. Studies have shown that Māori children are overrepresented when it comes to hospital admissions for accidental poisoning.
Given the negative impact and disproportionate effect on certain communities, this study focused on developing solutions to prevent accidental paracetamol overdosing of tamariki Māori. The intention was that these findings could then also be translated to non-Māori children in Aotearoa, New Zealand.
The volume of paracetamol required for a therapeutic dose is based on a child’s weight. However, this can be difficult to calculate for parents and caregivers of rapidly growing children, many of whom might not have access to a scale or a weight-based dose calculator.
To further complicate things, liquid paracetamol is offered in two different strengths (250mg/5ml and 120mg/5ml) and households can often have unreliable access to accurate measurement equipment such as syringes to administer paracetamol.
In order to reduce the risk of paracetamol overdosing, we assembled a research team with members from the National Hauora Coalition, WēBē, the University of Otago and BIT.
The aim of our project was to investigate how paracetamol dosing was understood and administered by parents/caregivers of tamariki Māori and to create an intervention that would improve dosing accuracy.
The research team worked both with kaupapa-Māori aligned qualitative methods (e.g. the importance of whanaungatanga) and behavioural science, structured by BIT’s TESTS methodology. This enabled us to involve hundreds of caregivers, and centre their voices and ideas in the design and testing of solutions. The resulting research methodology was a participatory, mixed-methods approach, and included qualitative interviews, co-design workshops, and a randomised controlled trial (RCT). The study was Māori-led but undertaken by Māori, Pākehā, Pacific and tauiwi researchers.
From our sessions with whānau, the research team identified a number of promising solutions; including fridge magnets with a table of appropriate doses for corresponding weights, a paracetamol phone app containing useful functions to assist caregivers with safe paracetamol dosing, and an educational video clip.
However the two most promising solutions were:
As a result we devised a redesigned bottle label (see below) and examined the potential options for an accompanying syringe.
Whānau in our workshops and user testing interviews also suggested several improvements to existing syringes, including measurement markings that did not wash off, and colour coding. We also prototyped a novel 3D printed syringe that used a locking mechanism to prevent large overdoses. (Unfortunately this experimental design did not prove to be functional.)
Eventually for the RCT, we selected a slim, ElmPlastics 5mL syringe with 0.1ml markings that is distributed with over-the-counter Pamol (but not prescribed paracetamol). This syringe is longer and thinner than a regular syringe, and has measurements on the plunger rather than the barrel (see images below).
Finally, we evaluated the intervention syringe and an adapted label in a randomised control trial (RCT) with almost 1000 parents or caregivers across Aotearoa.
Approximately, half of the participants were asked to use the measurement device that they would usually use at home (i.e. a spoon, a measuring cup, the lid of the paracetamol bottle, a typical 5 mL syringe) – these participants acted as our control group. The intervention group used the ElmPlastics 5 mL dosing syringe.
Participants in the control group saw a label typical of those provided with prescribed paracetamol, while participants in the intervention group saw the revised, whānau-informed label.
Participants in the intervention group – who used the ElmPlastics 5mL syringe and were provided the adapted label – were 34% more accurate at dosing paracetamol than the control participants who used the apparatus that they would usually use at home.
As a result, the caregivers who used the intervention syringe were 70% less likely to make a clinically significant overdose (more than 50% of the relevant prescribed dose) than participants in the control group (see plot below).
While the design of our study doesn’t tell us if it was the intervention syringe or label that improved dosing precision, our findings suggest that, to reduce paracetamol dosing errors and overdosing, whānau would be well served to be enabled to use the intervention syringe and label.
We believe there is huge merit in scaling up the solutions arrived at in this study. Ideally, when health practitioners prescribe paracetamol to caregivers of younger tamariki, they should provide caregivers with a syringe and the intervention label on paracetamol dosing.
There are further improvements that could be made to both the syringe (and label) that could be worth exploring. These changes to the shape of the syringe to make it more practical and using engraved mL markings on the barrel to ensure syringes are reusable and the markings don’t rub off. If cost is not prohibitive, it is also worth exploring putting colour bands on syringe barrels.
When prescribing paracetamol, it is well worth health practitioners – pharmacists, GPs, or nurses – taking the time to give caregivers clear information about paracetamol, especially the risks and harms of giving too much, and then providing the space to ask questions about paracetamol dosing.
Senior Research Advisor
Associate Advisor
WēBē
National Hauora Coalition
National Hauora Coalition
National Hauora Coalition
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