ISMP calls for elimination of dosage cups with multiple scales

July 6, 2015

The Institute for Safe Medication Practices (ISMP) issued a warning in June to stop using dosing cups for liquid medicine that are embossed with scales for drams, ounces, teaspoon, and tablespoon measures. These measurement scales can be easily confused with the milliliter dosing scales.

The Institute for Safe Medication Practices (ISMP) issued a warning in June to stop using dosing cups for liquid medicine that are embossed with scales for drams, ounces, teaspoon, and tablespoon measures. These measurement scales can be easily confused with the milliliter dosing scales.

My most serious pharmacy mistake

In a recent report to the ISMP National Medication Errors Reporting Program, a nurse confused the archaic measure of drams with milliliters. The nurse gave an opioid-naïve hospice patient close to 75 mg of morphine sulfate oral solution, instead of 20 mg/mL. One dram is equivalent to 3.7 mL. The patient died.

“To prevent mix-ups between variable systems, multiple national organizations have called for the adoption of the metric system (milliliter) as the standard for prescribing and measuring doses of liquid medications,” ISMP reported. These organizations included the American Society of Health-System Pharmacists, the American Pharmacists Association, FDA, ISMP, and others.

ISMP recommends that cups with multiple dosing scales be replaced with oral syringes that measure only in milliliters. If a dosing cup is used for liquid medications, the scale should only contain the milliliters scale.

“Make sure your purchasing group or department knows what type of cup to purchase. Also, only purchase dosing cups that have printed, rather than embossed, measurement scales, so they are easier to read,” ISMP recommended.