ISMP Safe Medicine May/June 2010, Volume 8, Number 3. ©2010 ISMP
Brand name medicines appear in green;
generic medicines appear in red.
Use an oral syringe or dropper to measure children's medicines, not a dosing cup
Many children’s liquid medicines come with a special plastic cup to help measure the exact dose. However, a recent study shows that parents often make mistakes when using these dosing cups to measure their children’s medicine. The study was published in a February 2010 pediatric medical journal.1
The study involved more than 300 parents, mostly mothers. The parents were asked to measure 1 teaspoon (5 mL) of acetaminophen (Tylenol) using these measuring devices:
- A clear plastic dosing cup with markings (tsp, mL) printed in black
- A clear plastic dosing cup with markings (tsp, mL) etched into the plastic
- A dropper
- A dosing spoon
- An oral syringe with an adapter that fits onto the bottle of medicine
- An oral syringe without an adapter.
Acetaminophen is a medicine that parents often give to children. It is used to lower a fever or ease pain associated with childhood illnesses. Many different companies make acetaminophen for infants and children, but they do not all include the same type of measuring device. For example, acetaminophen infant drops include a dropper, while acetaminophen elixir for children includes a dosing cup, dosing spoon, or oral syringe. The different types of measuring devices used in the study match the different devices provided by companies that make acetaminophen.
Overall, the accuracy of measuring the dose in both the cup with printed markings and the cup with etched markings was poor. Using the cup with printed markings, three out of four parents (70%) made mistakes. Using the cup with etched makings, half (50%) of the parents made mistakes. Almost all of the mistakes involved measuring out too much medicine. More than a third of the mistakes were considered large overdoses, which can be very serious in children.
Parents who make mistakes when using dosing cups are often confused about the differences between teaspoons and tablespoons. (One teaspoon equals 5 mL, one tablespoon equals 15 mL.) Some mix up the “tsp” (teaspoon) and “tbsp” (tablespoon) markings because they look so similar. Others assume that the entire cup is the correct dose. However, the entire cup typically holds up to 30 mL.
Most parents in the study were able to accurately measure the dose using a dropper, oral syringe, or dosing spoon. Using a dropper, only 6% of the parents made mistakes while measuring the dose. Using an oral syringe, with or without an adapter, about 10% of parents made mistakes. Using a dosing spoon, 14% made mistakes. A dosing spoon is different than a kitchen teaspoon. A dosing spoon is designed to measure an exact dose of medicine, whereas the amount of liquid held by household teaspoons varies a lot.
The study also found that the ability to accurately measure doses using a dropper or oral syringe did not depend on how well informed the parents were about health issues in general (often referred to as “health literacy”). The dropper and oral syringe were found to be much easier for parents to use without prior experience or directions from their healthcare providers.
Here’s what you can do: Healthcare professionals use oral syringes and droppers to accurately measure medicine doses; so should parents. If your child’s medicine comes with a dropper, use it to measure the dose of medicine. If your child’s medicine comes with a dosing cup, it might be safest to ask your pharmacist to recommend an oral syringe for you to use. Never use a household teaspoon or tablespoon to measure the dose. If the liquid medicine does not come with a measuring device, ask your pharmacist to recommend one. Whether your child’s medicine is an over-the-counter (no prescription needed) or prescription medicine, it is always best to verify with your pharmacist that you know how to measure the correct dose.
Reference: 1) Shonna Yin H, Mendelsohn AL, Wolf MS, et al. Parents’ medication administration errors: role of dosing instruments and health literacy. Arch Pediatr Adolesc Med. 2010;164(2):181-186.