An archaic dosing cup still used in some health care facilities that includes the measure drams caused a nurse to administer roughly 75 mg of morphine to an opioid-naive hospice patient. The nurse misread the scale marked drams as mL and gave the patient 1 dram of morphine sulfate solution instead of 1 mL. One dram is equivalent to 3.7 mL.

The fatal event was reported to the Institute for Safe Medication Practices’ (ISMP) National Medication Errors Reporting Program.

In an effort to prevent future mixups, multiple national organizations, including APhA, the American Society of Health-System Pharmacists, CDC, and others, are calling for the adoption of the metric system (milliliter) as the standard for prescribing and measuring doses of all liquid medications.

“Health care providers should stop using dosing cups that include a scale that measures in drams,” read a National Alert Network memo.

In place of these outdated measuring cups, available oral syringes that measure only in mL should be used whenever possible. If a dosing cup must be used, ideally it should allow measurement in mL only. The memo also warned that dosing cups that have printed, rather than embossed measurement scales, should be purchased because they are easier to read.