Please Read This If You Fill Your Pet's Prescriptions at Retail Pharmacies

By Dr. Becker

A few months ago, the Oregon Veterinary Medical Association (OVMA) conducted a survey to evaluate how frequently mistakes are made by retail pharmacies that fill veterinary prescriptions.

Thirty-five percent of Oregon veterinarians who responded to the survey had experience with retail pharmacy prescription errors. Typically, an online or retail pharmacy changed either the dosage or the medication itself without the DVM’s authorization.

Examples of Veterinary Prescription Errors

Seventeen percent of the vets with first-hand knowledge of prescription errors also had patients whose health suffered due to a medication error. Problems the veterinarians cited included:

• Multiple instances of substitutions of one type of insulin for another to save the client money. The pharmacists assumed the products were interchangeable. One pet suffered diabetic ketoacidosis as a result of this situation, and others received lower dosages than they required to treat their diabetes.
• Lowered doses of thyroid drugs without consulting the prescribing DVM. Apparently the pharmacists assumed absorption and metabolism of medication in pets is the same as it is in humans.
• A pharmacist told a pet owner the prescribed dose of anti-seizure medication was too high and recommended she cut it in half. The dog continued to have seizures for several weeks and ultimately had to be euthanized.
• A pharmacy substituted hydrocodone with acetaminophen for a medication prescribed for coughing in a dog with a collapsed trachea. In another case, a pharmacist advised a customer to give her dog high doses of Tylenol for arthritis pain. High doses of acetaminophen can cause irreversible liver damage in dogs, and there is no safe dosage of this drug for cats.
• A retail pharmacist dispensed azithromycin instead of the prescribed chemotherapy drug azathioprine. The animal relapsed and had to be euthanized.

Other reported problems included prescriptions dispensed at 10 times the correct dose, pharmacists ignoring prescription instructions reading “No substitution,” and pharmacists scaring pet owners by describing a drug’s side effects on humans, even though those side effects do not occur in animals.

I had one pharmacist insist the dose of thyroid medication I was prescribing was too high, and would not fill the prescription for my client over the weekend, instead suggesting the owner contact us Monday morning to report the error. I had to call the pharmacist and explain that dogs, pound for pound, require a much higher dose of thyroid medication than humans and that indeed, the prescription was correct.

Recommendations for Prescribing Veterinarians

In an effort to reduce veterinary prescription errors, the FDA’s Center for Veterinary Medicine (CVM) recommends prescribing veterinarians do the following:

• Avoid using abbreviations. Write out the full drug name and dosing instructions, including the dose, frequency, duration and route of administration.
• Do not use trailing zeros when writing out a dose, but do use a leading zero. A 5-milligram dose written as 5.0 can be misread as 50 mg. An 0.5 milligram dose written without the leading zero can be misread as 5 mg, which is 10 times the intended dose.
• When prescribing a human drug for an animal, verbally state (if the script is called in) or write out the entire prescription because some pharmacists are unfamiliar with veterinary abbreviations.
• Consider using a computerized prescription system to reduce the risk pharmacists might misread handwritten information.

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Other States to Evaluate the Problem

Other state veterinary medical associations have conducted or are planning to conduct similar research to determine the extent of the problem in their states.

Glenn Kolb, OVMA Executive Director, thinks veterinarians need to raise awareness among pet owners by telling them, “If a pharmacist suggests changing to a different drug or different dosage, please contact me right away.’”

“When a pharmacist counsels clients or makes changes to a prescription beyond the scope of their expertise, they’re in violation of their state practice act,” Kolb says. “We want to make sure that if pharmacists have any questions, they contact the veterinarian.”

What Pet Owners Can Do

The majority of human pharmacists get little to no training in veterinary pharmacy. Only a handful of pharmacy schools even offer a course in the subject. And most pharmacists aren’t knowledgeable about animal physiology.

If you plan to fill your pet’s prescription at a retail pharmacy or online, I recommend you do business only with pharmacies that are run by pharmacists familiar with veterinary prescriptions.  

As your pet’s advocate, I also recommend you speak personally with the pharmacist to insure he or she follows proper procedures when filling veterinary prescriptions.