The Institute for Safe Medication Practices (ISMP) has long recognized the frequency of mix-ups resulting from the non-standardization of units utilized in measuring volume of oral liquid medications. Since 2009, ISMP has strongly encouraged all practitioners to solely utilize the metric system for measuring oral liquid doses.
The National Council for Prescription Drug Programs (NCPDP) supports the use of the milliliter (mL) as the standard unit of liquid measure for prescription oral liquid medications. In addition to encouraging the use of the milliliter unit alone for such products, NCPDP stresses that dose amounts should always include leading zeros before the decimal point when the amount is less than one milliliter and should not include trailing zeros after a decimal point. For instance, directions for eight tenths of a milliliter should be written as 0.8 mL and never .8 mL where the decimal point can be overlooked and the dose misinterpreted as 8 mL. Similarly, utilize 2 mL rather than 2.0 mL which can be confused as 20 mL. Altogether avoid the use of the teaspoon or other non-metric measurements for all patient instructions.
Always ensure that patients have a measuring device marked clearly in milliliters only to prevent errors. For further patient safety, ISMP recommends that patients and/or caregivers be coached on use and cleaning of oral liquid measuring devices, utilizing the “teach back” approach to ascertain whether or not training is understood.
- NCPDP recommendations and guidance for standardizing the dosing designations on prescription container labels of oral liquid medications. http://www.ncpdp.org/Education/Whitepaper. March 2014
- ISMP 2014-15 targeted medication safety best practices for hospitals, best practice 5. ismp.org/tools/bestpractices/TMSBP-for-Hospitals.pdf.