The U.S. Food & Drug Administration is requiring labeling changes to three critical care medications that are approved for use in people and are also used in animals in the practice of veterinary medicine. Veterinarians who use these products in animals should be aware of these changes.

The labeling changes affect epinephrine injection, isoproterenol hydrochloride injection and neostigmine methylsulfate injection for use in people. FDA is requiring drug manufacturers to remove ratio expressions of strength (such as 1:1,000 and 1:10,000) from the labeling of these products. Strength will now be expressed only as the amount per unit of volume (mg/mL). For example, once these changes are made, the labeling for "Epinephrine Injection, USP, 1:1,000" will state "Epinephrine Injection, USP, 1 mg/mL."

Several reports of medication errors in human patients indicated that medication strength expressed as a ratio on product labeling was confusing to health care providers and contributed to the errors, FDA said.

These products are approved for use in people, but veterinarians are legally allowed to use approved human drugs for extra-label uses in animals under specified conditions. Extra-label use means using an approved drug in a way that isn’t in accordance with the approved labeling. It is sometimes called off-label because the use is “off the label.”

FDA provided the following additional information:

* Single Entity Injectable Drug Products;

* The Ins and Outs of Extra-Label Drug Use in Animals: A Resource for Veterinarians;

* Veterinary Medication Errors.