Tuesday July 15 2014
Many parents misinterpreted dosage instructions
“Using a spoon to measure medicine for children can lead to potentially dangerous dosing mistakes,” the Daily Mail reports.
Parents have long been instructed to provide liquid medication to their children in dosages measured using teaspoons and tablespoons. The rationale behind the advice is that this provides a quick and easy way for parents to calculate the correct dose.
However, a new study suggests that many parents misinterpret this advice, leading to either under or overdosing, which could be potentially harmful for a child.
The study involved 287 parents of children aged under nine years who were prescribed a daily oral liquid medication for two weeks or less.
After the end of the medication course, parents were asked about the dose of medication they were supposed to be giving their child and how they measured it.
The researchers found that dosing errors of medications are common, with nearly a third of parents making an error in knowledge of the prescribed dose. Around one in six parents used a kitchen spoon rather than a teaspoon or tablespoon to measure out liquid medicines.
The researchers found that errors were less common when the unit of measurement used to describe the dose was millilitre rather than teaspoon/tablespoon.
The researchers conclude that this suggests moving to a millilitre-only standard – which can be delivered using a dropper, oral syringe or dosing spoon – as this could reduce confusion and decrease medication errors.
Where did the story come from?
The study was carried out by researchers from New York University School of Medicine, Bellevue Hospital Center and Woodhull Medical Center in New York, and Pennsylvania State University College of Medicine.
It was funded by the US National Institutes of Health, the National Institute of Child Health and Human Development and Nation Center for Research Resources.
The study was published in the peer-reviewed journal Pediatrics.
The research was well reported by the Daily Mail.
What kind of research was this?
This was a cross-sectional study, with information gathered at one point in time.
The researchers were concerned about the lack of standard units of measurement for oral liquid medications for children.
Instead, parents may be told to measure doses in:
- millilitres (ml)
- cubic centimetres
Understandably, this can lead to confusion.
In addition, the researchers were also concerned about expressing doses in teaspoons and tablespoons, because if parents mix-up these units it can lead to children being given either a third or three times the intended dose. One teaspoon is equivalent to 5ml and one tablespoon is equivalent to 15ml.
Furthermore, expressing doses in this way may lead to kitchen spoons being used to measure doses, and these vary widely in size and shape.
What did the research involve?
The researchers studied 287 parents of children aged under nine years who were prescribed a daily oral liquid medication for two weeks or less at one of two hospital paediatric emergency departments in New York.
Between four days and eight weeks after the end of the prescribed medication course, parents were asked to report the dose they gave their child, and the researchers performed a dosing assessment.
In the dosing assessment, researchers watched parents after they were asked to dose the medication as they would at home.
They were given a standard medication bottle and asked to use the dosing instrument they used or to select a comparable one from a range provided. The range consisted of a kitchen teaspoon, kitchen tablespoon, dosing spoon, measuring spoon, dosing cup, 5ml dropper, acetaminophen (the US term for paracetamol) infant dropper, ibuprofen-specific dropper and 1-, 3-, 5-, 10- and 12-ml oral syringes.
The researchers compared the results with the prescribed dose to see if there was an error:
- in knowledge of the child’s prescribed dose
- in measurement compared to the parent’s intended dose (dose the parent reported giving)
- in measurement compared to the child’s prescribed dose
To be classified as an error the difference had to be more than 20%.
The researchers looked at if the likelihood of an error depended on:
- whether parents used a nonstandard dosing instrument (kitchen teaspoon or tablespoon)
- the unit of measurement used
The researchers adjusted their analyses for child and parent age and gender, parent-preferred language, ethnicity, level of education, socioeconomic status, parent health literacy and child’s chronic disease status.
What were the basic results?
The researchers found that:
- nearly a third (31.7%) of parents made an error in knowledge of the prescribed dose
- about 40% (39.4%) made an error in measurement of dose compared to the parent’s intended dose
- about 40% (41.1%) made an error in measurement of dose compared to the child’s prescribed dose
- around one in six parents (16.7%) used a kitchen spoon rather than a standard measurement instrument (oral syringe, dropper, dosing cup or spoon, or measuring spoon)
The researchers found that units of measurement in the child’s prescription, on the medication bottle, and that the parent reported often did not correspond, with the bottle label not containing the same units as the prescription more than a third of the time (36.7%), and parents not using the unit listed in the prescription or label. The researchers thought that parents were likely to have been exposed to different units as part of verbal instructions from the clinician prescribing the medication.
Units of measurement on the prescription or the bottle were not associated with errors in knowledge or measurement; however, the unit reported by the parent was associated with both types of error:
- Compared with parents who used ml only, parents who used teaspoons or tablespoons were more likely to make errors in measurement compared to their intended dose (adjusted odds ratio [AOR] 2.3; 95% confidence interval [CI], 1.2 to 4.4) and to the prescribed dose (AOR = 1.9; 95% CI, 1.03 to 3.5)
- Parents who reported their dose using teaspoon or tablespoon units were more likely to use a nonstandard instrument than those who used ml.
- Parents using a nonstandard instrument had more than twice the odds of making an error in measurement compared with both their intended (AOR = 2.4; 95% CI, 1.1 to 5.0) and prescribed (AOR = 2.6; 95% CI, 1.2 to 5.5) doses.
How did the researchers interpret the results?
The researchers conclude that their findings "support a millilitre-only standard to reduce medication errors”.
This US cross-sectional study has found that parent dosing errors of medications for children are common. Around one in six parents use a kitchen spoon rather than a standard measurement instrument to measure out liquid medicines.
It also found that errors were less common when the unit of measurement was ml rather than teaspoon/tablespoon.
A limitation of this study was that parents were assessed between four days and eight weeks after the end of the child’s prescribed medication course, meaning that memory could have had an impact. There is also the possibility that the accuracy was actually even worse than they observed, as the parents are likely to have been paying full attention to measuring the medication during the supervised assessment, rather than having distracting children around. There would also be a likelihood that they would not have wanted to “fail” the test.
In addition, as this is a cross-sectional study, it cannot show that the unit of measurement caused the errors in measurement.
However, overall, the main findings of the study would certainly seem to support the researchers’ call for a standard unit of measurement to avoid potential confusion.
In the UK, many of the leading manufacturers of liquid medication for children provide oral syringes or droppers with the medication, so this may be less of a problem than in the US.
If in doubt about any aspect of the use of children’s medication, ask your pharmacist for advice.
Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter. Join the Healthy Evidence forum.