When Measuring Medicines, Not All Spoons are Created Equal

Using kitchen spoons to measure liquid medication can lead to significant overdosing or underdosing, reports a new study from Cornell University. Published in a recent issue of the Annals of Internal Medicine, the study found that 70% of people who take liquid medicine use silverware spoons to measure doses.

In the Cornell study, almost 200 college students who had recently visited their university health center were asked to pour liquid medication into a kitchen spoon. The researchers found that the students underdosed by more than 8% when using medium-size spoons, and overdosed by an average of almost 12%—up to 20%— when using larger spoons. Yet, participants were confident that they had poured correct doses in all the test cases.

"Although these educated participants had poured in a well-lit room after a practice pour, they were unaware of their biases," said consumer behavior expert Brian Wansink, who led the study.

Over the course of a day or days, taking medication every four to six hours, this error in dosing adds up, Wansink said. "It can lead to overdosing, or also to underdosing, potentially to beneath the point of effectiveness." He added that the college-student study participants poured the medication in midday when well rested in a well-lighted room. "But in the middle of night, when you're fatigued, feeling miserable or in a rush, the probability of error is undoubtedly much greater," he said.

Since a medicine's efficacy is often linked to its dose, consumers should use a measuring cap, dosing spoon, measuring dropper or a dosing syringe, "rather than assume they can rely on their pouring experience and estimation abilities with tablespoons," concluded Wansink.

Source: Cornell University. Koert van Ittersum of Georgia Tech's College of Management co-authored the study.

To Learn More

When it comes to medications, seniors are especially vulnerable to both overdosing and underdosing. For more information about the safe use of medicines, see "Senior Medication Problems: Home Care Can Help" in the January 2009 issue of Caring Right at Home.

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