Doctors urged to remember the importance of careful counselling around dosing instructions for a medication prescribed to those with ADHD after a recent study found poisonings had increased.
University of Sydney researchers found the number of Australians poisoned by ADHD medications in 2023 was four times what it was a decade earlier.
While the number of people diagnosed with ADHD has increased, that increase is not proportionate to the increase in poisonings, researchers said.
The study showed there were 3,242 such poisonings in 2023 compared to 795 in 2014, a quadrupling during a time when diagnoses only doubled.
Using nationwide data from the NSW Poisons Information Centre, researchers found more than half of the 17,000 self-reported cases in the period surveyed resulted in hospital admission, with more than 9,000 having involved children under 15 years of age.
Clonidine was initially designed to treat hypertension and is often prescribed as a quarter or a half dose of a tablet for those using it to treat symptoms of ADHD, with researchers warning that this raises the risk of dosing errors.
PhD candidate and lead author of the study Amy Thomson said: “While the sharp rise in the number of poisonings over the last decade can be partly explained by the rise in ADHD diagnoses, clonidine poisonings are outstripping diagnosis rates.”
“While medications are an effective way of managing ADHD, these drugs can pose a serious risk if accidentally or intentionally misused.
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“Just one double dose of clonidine can put a child in hospital and with side-effects this serious it’s vital that both families and healthcare professionals are aware of the dangers and providing families with guidance.”
Chair of the RACGP WA ADHD Working Group Dr Sean Stevens said clonidine was used in the strengths the medication currently comes in when being used as a blood pressure medication, but for ADHD it is often prescribed in parts of a tablet.
He said for that reason “it’s very easy for the doses to be inadvertently mixed up”.
Specialists initiate prescriptions for ADHD medicines in WA at the moment; however, a small cohort of GPs are currently in training to be able to do so as of next year.
Dr Stevens said it was important that specialists were clear in their discussions around medications and their instructions.
He said while GPs may not be initiating these medications to their patients, they could play an educational role.
“Making sure that it’s used appropriately and as prescribed, making sure that it’s out of reach of kids, making sure that people understand the risks of overdose,” he said.
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Clonidine is one of six medications used for the treatment of ADHD; the others are atomoxetine, dexamphetamine, guanfacine, lisdexamphetamine and methylphenidate.
National data from the NSWPIC showed clonidine and methylphenidate (branded as Ritalin) were the two most common medications involved in poisonings, each resulting in 35% of all reports.
They also accounted for the highest number of hospital presentations.
Children and adolescents were the most likely to have an adverse exposure to ADHD medication, with 72% of accidental poisonings taking place among children aged under 15 years.
Ms Thomson said as well as mix-ups over quarter and half doses, another reason behind some of the poisoning events had been miscommunication within families.
“Typically, where both parents give their child a dose of medication, not realising the other has already done it,” she said.
“Children can also be curious and ‘try out’ their siblings’ medication, underscoring the importance of storing medicines safely out of reach.”
While the research revealed that 60% of poisonings were accidental, more than a third, (38.5%) of poisonings were the result of deliberate misuse.
The researchers warned that because the data from the NSWPIC was self-reported, the scale of the problem could be much bigger.
“The self-reported data captures only those who phoned the poisons hotline or who presented to hospital with symptoms of poisoning,” Ms Thompson said.
“The true scale of the problem could be much more significant, which is why we want those with ADHD and their families to be better informed about the risks.”
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