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Pharmacy relations 101: Common sources of error and prevention strategies

dvm360dvm360 June 2021
Volume 56

Serious prescription errors have been reported when pet prescriptions are filled at community pharmacies. Awareness of why these errors might occur and strategies for prevention will help protect patient health and improve working relationships between veterinarians and community pharmacists.

pharmacist filling prescription

Viewfinder / stock.adobe.com

As the market for pet prescriptions expanded rapidly beyond the veterinary clinic, awareness of serious prescription errors has grown. There are numerous potential sources and causes of error, each with its own potential consequences. Although it can be frustrating for veterinarians to learn that an error has occurred with a patient’s medication, it is essential to remember that errors are not typically made with malicious intent. Similar errors can—and do—happen in a veterinary clinic.

Colleagues in the pharmacy work hard to fulfill their legal and ethical obligations to patient health and safety when filling prescriptions. Unfortunately, pharmacists receive minimal training in veterinary pharmacology. Results from a 2017 survey of pharmacists in North Carolina found that 91% of respondents reported no previous training in the subject.1 Because there can be large differences in use, route of administration, doses, and adverse effects for many medications among different species, the potential for errors is high when pharmacists lack species-specific knowledge or resources.

Understanding when and why errors occur and strategies for error prevention is essential for patient health and maintaining good working relationships between veterinarians and community pharmacists.

Potential prescription errors

In 2012, the Oregon Veterinary Medical Association (OVMA) conducted a member survey to collect data on the frequency of prescription errors when utilizing community pharmacies. Four other VMAs performed similar surveys in 2012 and 2013. In total, over 700 veterinarians responded, with approximately one-third reporting dispensing errors and 10% reporting harm to patients due to these errors.2

Dispensing of incorrect medication due to substitutions

One of the most serious potential errors that can occur is the dispensing of incorrect medication. Multiple cases were documented in the OVMA’s 2012 survey of prescription errors.3 The 2 primary reasons for this are miscommunication and inappropriate substitutions.

Medications with similar-sounding names, such as azathioprine and azithromycin, pose the largest risk of miscommunication. In extreme cases, these errors can result in patient death due to a lack of improvement (eg, prescription filled for azithromycin instead of azathioprine for an immune-mediated disease in a dog) or adverse effects of the wrong medication (eg, prescription filled for azathioprine instead of azithromycin for a cat, leading to bone marrow suppression).3

Regarding substitutions, there is more of a gray area. Pharmacists can legally substitute a generic medication for the brand name product or interchange manufacturers unless the prescriber specifies otherwise. Often, pharmacists make these substitutions to help clients save money.

A legal substitution could be problematic in a veterinary patient if one manufacturer’s product contains a toxin, such as xylitol, whereas another does not. If a veterinarian prescribed the specific manufacturer without specifying “no substitutions,” a pharmacist could legally dispense a different generic gabapentin suspension, resulting in potential toxicity to the patient.

Although some substitutions are legal, illegal substitutions are sometimes made, such as dispensing a drug related to but not interchangeable with the prescribed medication. While the prescribing doctor should approve these types of substitutions before dispensing the medication, this does not always happen. Examples that could be especially problematic for veterinary patients include:

  • cyclosporine (Sandimmune) in place of modified cyclosporine (Atopica, Neoral, or Gengraf). Although the unmodified product would provide cost savings, it is not as bioavailable in veterinary patients, leading to reduced efficacy. Technically, this is an illegal substitution because modified cyclosporine is considered a different drug.
  • prednisone in place of prednisolone. Veterinarians are well aware of the inability of cats to convert prednisone into the active form prednisolone and therefore, exclusively prescribe prednisolone. Humans can convert the prednisone prodrug into prednisolone without issue. However, pharmacists may be unaware of the difference between the 2 drugs for feline patients and might dispense prednisone if prednisolone is not in stock.4
  • an opioid in combination with acetaminophen in place of the opioid alone (eg, hydrocodone plus acetaminophen in place of Hycodan).

Alterations to medication strength or dose

Pharmacists are legally required to verify the accuracy and validity of each prescription they receive. If pharmacists are unaware of species-specific dose differences between humans and veterinary patients, they may advise clients that the dose prescribed by their veterinarian is too high or recommend a dose reduction. In a 2019 survey of veterinarians in Pennsylvania regarding prescription errors, 73% of respondents reported that a pharmacist had questioned the strength or dose of the prescribed medication.5

If the pharmacist is concerned about the dose and contacts the veterinary office before filling the medication, no patient harm occurs. However, this may put a strain on the relationship between the veterinary office and community pharmacy.

Concerns arise when pharmacists counsel owners to give a reduced dose or express their concern directly to the client. This can result in upset clients who are under the impression that their veterinarian made an error, or clients who do not administer the medication as prescribed. For a drug such as phenobarbital, the patient may experience complications because of the subtherapeutic dosing. In fact, the OVMA survey results included the case of a dog that was euthanized because of ongoing seizures after a pharmacist advised the owners to administer a reduced dose.3

Another common drug that raises concerns for pharmacists is levothyroxine. There is a large difference in dosing between humans (dosed in micrograms) and canines (dosed in milligrams) owing to differences in bioavailability, daily requirements, and half-life.4

Clients advised of incorrect adverse-effect profiles

Pharmacists play an essential role in the health care team for human patients and are required to offer counseling to patients on possible adverse effects and drug interactions. Because of a lack of training in veterinary pharmacology, pharmacists may counsel pet owners about adverse effects that are not applicable to animal patients. In humans, respiratory depression is a major concern with opioid medications but is rarely seen with oral opioids in veterinary medicine. Although this rarely results in direct harm to the patient, owners may become alarmed by the potential adverse effects, which may not be pertinent to their pet. The owners may elect not to have the prescription filled or administer the medication prescribed. In addition, veterinary offices may receive calls from clients who are upset the vet team did not advise them about these adverse effects.

Strategies for error prevention

Veterinary teams can help prevent prescription errors by ensuring clear communication and script transmission, building relationships with the pharmacy team, and educating clients.

Communication and script transmission

First and foremost, providing clear prescriptions is essential for reducing errors. Providing a written script is the best way to avoid communication errors and the most reliable way to track where an error occurred (ie, whether at the veterinary office or pharmacy), as a copy of the script can be kept in the patient’s chart.

When providing written scripts, typewritten is preferred. If a script is handwritten, ensure it’s legible. Avoid abbreviations, as they can be misinterpreted, especially “SID” instead of “once daily,” as this is not an abbreviation recognized in human medicine.6 Furthermore, be sure to denote “no substitutions” or “brand medically necessary” when substitutions are inappropriate.

Take additional steps to reduce errors, such as writing “no xylitol” for suspensions or orally disintegrating tablets, so the pharmacist is aware of the need to check this. Consider including additional information about patients, such as the weight, which may help the pharmacist when verifying doses, as a Chihuahua and Great Dane will have widely different doses for the same medication.

It is legal to provide a prescription over the phone for everything except Schedule II controlled medications; however, as the communication is verbal, tracking the source of an error is more difficult. Although it may be easier to leave a message, it is always better to speak to a live person who can confirm prescription instructions. Documentation of who received the prescription at the pharmacy and the exact instructions relayed should be made. Spell out information, especially drug names, and ask the pharmacist or pharmacy technician to repeat the order to verify accuracy.

Relationship-building with the pharmacy team

Building relationships with community pharmacists can go a long way toward reducing errors. Reaching out to local pharmacies to establish a relationship as an expert and invite them to call the office with any questions. Consider donating an old copy of an animal drug reference to a local pharmacy, as many do not have access to veterinary references. More tips on relationship-building with community pharmacists are available here.

Client education

The final strategy for reducing prescription errors is to make sure clients are well educated before leaving the office with a prescription. Clients should be made aware of what medication they will receive at the pharmacy and how it should be administered. Including written discharge instructions offers a way for the client to double-check whether they have received the right medication and that the dosing instructions match what they have received from the pharmacy. In most medical records systems, adding a discharge note to the bottom of an invoice only takes a few seconds.

In addition, for medications with large dosing differences between animals and humans, inform the client that the pharmacist may express concerns regarding the dose when they pick up the medication. Assure clients that the dosing is appropriate for their pet and encourage them to refer any concerns the pharmacist might express back to the office. The same can be done for any adverse effects that may not be applicable to veterinary patients.

What comes next

In the next article, other types of errors that may occur related to toxic ingredients and over-the-counter medications, concerns with insulin and insulin syringes, and how to report errors if they occur will be discussed.

Kate Boatright, VMD, is a 2013 graduate of the University of Pennsylvania, a practicing veterinarian, and a freelance speaker and author in western Pennsylvania. She is passionate about mentorship, education, and addressing common sources of stress for veterinary teams and recent graduates. Outside of clinical practice, Boatright is actively involved in organized veterinary medicine at the local, state, and national levels.

Lauren Forsythe, PharmD, DICVP, is a 2015 graduate of the University of Findlay, College of Pharmacy. She completed her veterinary pharmacy residency at Purdue University Veterinary Teaching Hospital. After her residency, she spent 3 years as a veterinary clinical pharmacist at the University of California Davis Veterinary Medical Teaching Hospital and is now the medication dispensary coordinator at the University of Illinois Veterinary Teaching Hospital. She is a diplomate of the International Society of Veterinary Hospital Pharmacists. In addition to her full-time veterinary pharmacy career, Forsythe has experience working in a retail pharmacy.


  1. Young NW, Royal KD, Park M, Davidson GS. Pharmacists’ knowledge of veterinary pharmacotherapy and the impact of an educational intervention. J Pharm Technol. 2018;34(6):244-251. doi:10.1177/8755122518794023
  2. Cima G. Substitution errørs. J Am Vet Med Assoc. 2014;245(5):462-465. doi:10.2460/javma.245.5.462
  3. Kolb G. Veterinary Prescriptions & Retail Pharmacies Summary - Membership Survey. Oregon Veterinary Medical Association, September 2012. Accessed August 22, 2018. https://www.ftc.gov/sites/default/files/documents/public_comments/request-comments-and-announcement-workshop-pet-medications-issues-project-no.p121201-560891-00569/560891-00569-84588.pdf
  4. Frankel G, Kusno A, Louizos C. Five things every community pharmacist should know when dispensing for 4-legged patients. 2016 Mar;149(2):NP1]. Can Pharm J (Ott). 2016;149(2):99-106. doi:10.1177/1715163516628543
  5. Unpublished data from a 2019 survey of Pennsylvania veterinarians regarding prescription errors when using retail pharmacies. Conducted by Dr. Brian Langlois, past president of PVMA.
  6. Kim-Jung L. A microgram of prevention is worth a milligram of cure: preventing medication errors in animals. FDA. Accessed April 4, 2021. https://www.fda.gov/AnimalVeterinary/ResourcesforYou/ucm214772.htm#FDA_s_Initiative
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