The U.S. Food and Drug Administration (FDA) is requiring labeling changes to three critical care medications used for people and animals.

On June 20, the FDA announced the labeling changes that affect epinephrine injection, isoproterenol hydrochloride injection, and neostigmine methylsulfate injection. Drug manufacturers must remove ratio expressions of strength from the labeling of these products. Ratio expressions of strength are a way to express the strength of a solution or liquid preparation. The ratio 1:1,000 represents 1 gram of epinephrine in 1,000 mL of solution.

The change is being made due to several reports of medication errors in human patients that indicated using the ratio expression of strength was confusing to healthcare providers. Errors including giving undiluted epinephrine 1:1,000 (1 mg/mL) to patients instead of the 1:10,000 (.1 mg/mL) concentration. Ratio expressions can be hard to differentiate and the error of a mistaken ratio can lead to serious adverse outcomes.

Changes may already be present on medication in the market, and the FDA will continue to work with manufacturers to change labels.

Strength will now only be expressed as the amount per unit of volume (mg/ML). For example, the labeling for epinephrine injection, USP, 1:1,000 will now read epinephrine injection, USP, 1 mg/mL.

Veterinarians should start prescribing, communicating, dispensing, and labeling these drugs in mg/mL rather than ratios. In addition, practices should review systems, processes, and storage areas that are affected by this labeling standard.

The Institute for Safe Medical Practices (ISMP) has created a checklist to help with successful transition and that checklist can be found here.

For information on the changes, you can go to the FDA’s website.

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