EpiPen Jr dose confusion


A mother picked up her child’s EpiPen Jr (epinephrine) autoinjector at a local pharmacy. Her child’s doctor had prescribed the autoinjector to use in an emergency caused by a severe peanut allergy. The mother was confused by the instructions printed on the pharmacy label: “Inject 0.3 mL intramuscularly one time as needed for anaphylaxis.” However, the strength of the EpiPen Jr autoinjector is displayed on the carton as 0.15 mg (Figure 1). The child’s mother was not sure why the pharmacy label said “0.3” while she was holding a carton that stated “0.15.”

The mother confused the units “mg” with “mL” and mistakenly thought the child’s emergency dose was 0.3 mg, not 0.3 mL. So, she thought she needed to use both pens in the carton (2 x 0.15) to administer the dose printed on the pharmacy label (0.3). Thankfully, she reached out to a relative who happened to be a pharmacist. Her relative explained that each pen holds 0.15 mg of epinephrine per 0.3 mL of medicine. (The amount of medicine [mg] per volume [mL] is called the concentration.) So, the child’s dose in an emergency would be the contents of one pen (0.3 mL, or 0.15 mg), not two pens. It should be noted that, on the side of carton, the concentration of the EpiPen Jr is listed as 0.15 mg/0.3 mL. However, this may not be noticed or helpful to consumers.   

figure 1 epi

In this case, the child did not receive the wrong dose. However, confusion related to the pharmacy instructions for using a medicine has contributed to many similar errors. Normally, instructions for oral liquid medicines would include the number of milliliters (mL) to take for each dose, as oral dosing devices (cups, oral syringes, droppers) are typically marked in mL. However, injectable medicines are typically labeled in milligram (mg) strengths. So, errors have occurred when pharmacy instructions list the dose to take in mL instead of mg. Confusion between mg and mL is common. The pharmacy should include instructions that clearly explain how to take the medicine, matching the most prominent dose listed on the package and device (pen, cup, syringe, dropper).

Here’s what you can do: When you pick up a medicine from the pharmacy, ask the pharmacist to go over the instructions for taking the medicine. This is critical to safely using an epinephrine autoinjector during an emergency. Specifically show the pharmacist how you will use the auto-injector to be sure you understand the instructions for use.

Created on October 30, 2020

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