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The Medical Minute: Metric units make for more accurate medication doses

Before giving a child medication, don't reach into the kitchen drawer and grab a spoon. Instead, use a syringe that uses metric units and be sure the dose is accurate.

The American Academy of Pediatrics (AAP) recently issued a set of recommendations on how orally-administered medications should be both prescribed and given to a child. Penn State Hershey Children's Hospital pediatrician Dr. Ian Paul was the lead author of these recommendations as part of the academy's Committee on Drugs.

“It's important to educate people that  medication errors and overdoses are common, but most are preventable,” Paul said. Each year, more than 70,000 emergency department visits occur due to unintentional overdoses.

The AAP recommends that pediatricians write prescriptions in metric units using milliliters (mL), which will help children receive a more precise amount of medication.

“There's a variation in tablespoons and teaspoons that people use at home,” Paul said. “People sometimes confuse tablespoons and teaspoons, and give their child too much medicine. Parents should administer both over the counter and prescription medications with a syringe that has metric units, preferably one that has a flow restrictor.”

Syringes are available at any drug store and should be provided free with prescription medication upon request. A dosing cup with metric markings is an acceptable alternative, but a syringe is preferred.

The AAP's recommendations for health care providers, caregivers and the medication industry include:

  • Orally administered liquid medications should be dosed exclusively by using metric-based dosing with milliliters (mL) to avoid confusion and dosing errors associated with common kitchen spoons.
  • The only appropriate abbreviation for milliliter is “mL,” and the use of alternatives (eg, ml, ML, cc) for dosing orally administered liquid medications should be avoided.
  • Milliliter-based dosing should include leading zeros preceding decimals for doses less than 1 mL (eg, 0.5 mL) to avoid 10-fold dosing errors.
  • Trailing zeros after decimals should not be included when dosing in whole number units to avoid 10-fold dosing errors.
  • The concentration (strength) of all orally administered liquid medication (eg, in milligrams per milliliter [mg/mL]) should be clearly noted on prescriptions to enable accurate calculation of the medication dose administered.
  • Pediatricians should review milliliter-based doses with patients and families at the time that orally administered liquid medications are recommended or prescribed to ensure adequate health literacy for metric dosing units.
  • Pharmacies, hospitals, and health centers should dispense orally administered liquid medications with metric dosing on the label and should distribute appropriate-volume milliliter-based dosing devices with all orally administered liquid medications.
  • Syringes (optimally, those designed to partner with flow restrictors) are the preferred dosing device for administering oral liquid medications. Cups and spoons calibrated and marked in milliliters are acceptable alternatives.
  • Dosing devices should not bear extraneous or unnecessary liquid measure markings that may be confusing to caregivers.
  • When possible, dosing devices should not be significantly larger than the dose described in the labeled dosage to avoid twofold dosing errors.
  • Manufacturers should eliminate labeling, instructions, and dosing devices that contain units other than metric units.
  • Researchers should study the effect of caregiver health literacy on dosing precision to determine the best strategies to prevent unintended dosing errors among minorities, immigrants, and those with low health literacy.

The Medical Minute is a weekly health news feature brought to you by Penn State Milton S. Hershey Medical Center. Articles feature the expertise of Penn State Hershey faculty physicians and staff, and are designed to offer timely, relevant health information of interest to a broad audience.

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