Concentration labeling changed for epinephrine, two other medications

Three human-use pharmaceuticals used in veterinary medicine will be sold with labels containing revised descriptions of drug concentrations.

The Food and Drug Administration, in a June 20 notice, said veterinarians should be aware of the changes to labels for epinephrine injection, isoproterenol hydrochloride injection, and neostigmine methylsulfate injection. The agency is requiring that drug manufacturers remove ratios to express drug concentrations, such as 1:1,000, and instead use only the amount of drug per unit volume, such as 1 mg/mL.

"There have been several reports of medication errors indicating that ratio expressions are confusing to healthcare providers and contributed to the errors," additional FDA information states. "Some of the medication errors resulted in serious adverse outcomes, including death."

Another organization, the Institute for Safe Medication Practices, had found that ratio expressions could be difficult to differentiate in small print, especially when numbers were typed without commas, the FDA information states. That organization also found that health care providers misunderstood the concentrations represented by ratios.

The observations by the ISMP led to evaluation of the ratio expressions by the United States Pharmacopeia, a standard-setting scientific nonprofit. The USP implemented a new standard, effective May 1, 2016, on concentration labeling for single-entity drug products, and federal law requires that drug products named in the USP or National Formulary be packaged and labeled as described in that compendium, FDA information states.