Markings on Oral Syringes Can Be Confusing
(Be Sure to Measure Liquid Medicines Accurately)
An oral syringe is a useful tool for measuring the correct dose of a liquid medicine.
- Oral syringe with scales for measuring teaspoons on the left and millilitres on the right.
Most oral syringes are marked with two scales. One scale is for measuring the dose in
millilitres (mL). The second scale is for measuring the dose in teaspoons. One
teaspoon is the same as 5 mL.
ISMP Canada has received a report about markings on an oral syringe that caused
confusion and led to a medication error. A doctor prescribed a liquid antibiotic for a
baby. The medicine came with an oral syringe for measuring the dose. The prescribed
dose was 2 mL, but the child's caregiver mistakenly measured a dose of 2 teaspoons.
As a result, the baby received 10 mL of the antibiotic—5 times the intended dose.
After receiving this incorrect dose, the baby suffered vomiting and diarrhea over the
next 24 hours.
If you must take a liquid medicine, or if you are giving a liquid medicine to someone
else, be sure you know how to measure the dose accurately. The best time to start
thinking about how to measure a liquid medicine is when you have the prescription
filled. If a measuring device is provided with the medicine, take the time to examine it
with the pharmacist before you leave the pharmacy. Show the pharmacist how
you would measure the medicine. Repeat back any special instructions in your
own words. This will help the pharmacist to know if you have understood the
Never measure liquid medicines with household spoons or with measuring spoons
designed for cooking. These utensils are not accurate enough to measure medicine.
Using them could cause you to take (or give) a dose that is too high or too low. Instead
of using your household spoons, always use the measuring device provided with your
medicine. If a measuring device is not provided with your medicine, ask your
pharmacist for help in selecting a suitable measuring device. You can also ask
the pharmacist for a demonstration. Devices for accurately measuring medicine
that are available from your pharmacy include oral syringes, medicine cups, and
Measurement errors with medicine can have serious consequences. Protect yourself
and your family by taking steps to measure liquid medicines accurately!