FDA urges veterinarians to avoid ambiguity when writing prescriptions for pets

Human pharmacists may misinterpret veterinary medication and dosage instructions, agency says.


The U.S. Food and Drug Administration (FDA) Center for Veterinary Medicine (CVM) began to examine error reports for veterinary medications in 2008. Now, safety reviewer Linda Kim-Jung of CVM’s Division of Veterinary Product Safety says that the medication errors that occur in the prescription of medicine to pets are similar to those that happen in the treatment of people.

According to a release from the FDA, Kim-Jung says errors can start with simple abbreviations—especially now that some clients have their veterinary prescriptions filled at retail pharmacies. Although veterinarians are taught to use abbreviations to save time, abbreviations taught on the human side may be different from those veterinarians use. “Poor penmanship can add to the problem, too,” Kim-Jung says. This can lead to transcription errors at the pharmacy.

In its review of error reports, the CVM found that dosing abbreviations are often misread. For example, “s.i.d.” (once daily) has been misinterpreted as “b.i.d.” (twice daily) and “q.i.d.” (four times daily), leading to overdoses. Transcription errors can also occur as a result of misinterpreting abbreviations such as “U” (units) for “0” or “mcg” (microgram) for “mg” (milligram), or when prescriptions are written with leading or trailing zeroes.

“A 5-mg dose written with the trailing zero as 5.0 mg can be misread as 50 mg, or a 0.5 mg dose written without the leading zero as .5 mg can easily be mistaken for 5 mg, potentially resulting in a 10-times overdose,” Kim-Jung says.

To avoid prescription mixups, the CVM recommends that veterinarians adopt the following practices:

• Completely write out the prescription, including the drug name and dosage regimen. The full dosage regimen includes the dose, frequency, duration and route of administration.

• When writing out a dose, do not use a trailing zero and do use a leading zero.

• When calling in or writing out a human drug prescription for animals, verbally state or write out the entire prescription, because some pharmacists may be unfamiliar with veterinary abbreviations.

• Consider using a computerized prescription system to minimize misinterpretation of handwriting.

The CVM also says programs should be considered at the veterinary school level to teach students about the dangers of using abbreviations.