Prescription medication errors are reported to be the most common type of error in human medicine, with a similar trend emerging in veterinary medicine as reporting and evaluation of errors become more common.1,2 In a study on self-reported medical errors in 3 veterinary hospitals, >54% of reported errors were drug related.1 Another study addressing medication-related errors in a large animal teaching hospital found 58.4% of identified errors occurred in the prescribing phase.2
Sending prescriptions to a pharmacy outside the clinic (eg, community pharmacy) increases the risk for errors because of possible miscommunication and training differences between pharmacists and clinicians. Following are tips from the author to help ensure patient safety by recognizing and avoiding key sources of prescription errors.
1. Limiting Opportunities for Misinterpretation
Human prescriptions are typically submitted to a pharmacy electronically, limiting misinterpretation caused by handwriting, abbreviations, or misspellings. Veterinary electronic medical record and practice information management systems do not currently offer electronic submissions to community pharmacies, but many of these systems can generate a printed prescription, which can eliminate misinterpretation of handwriting and incorrectly transcribed phoned-in prescriptions as well as provide a clear record. If a printed prescription is not available, using clear handwriting or spelling the name of the medication over the phone and having the recipient read it back can save time and prevent medical emergencies. For example, azathioprine and azithromycin are easily mistaken for one another, which can have serious effects.3 Techniques such as tall man lettering can help prevent errors involving drugs with names that look and/or sound alike.
Abbreviations and misuse of decimals should be avoided, particularly in handwritten prescriptions. The frequency abbreviation SID is not taught in most pharmacy schools and, because it is not recognized in human medicine, does not appear on the Institute for Safe Medication Practices list of abbreviations to avoid.4 SID has been misinterpreted as BID and QID, leading to significant overdoses.5 Administration frequency should be spelled out fully (eg, once daily) or expressed in hours (eg, every 24 hours). Unseen decimals can likewise have a significant impact. A helpful rule for decimals on prescriptions is Always lead, never follow, meaning a zero should always be included before a decimal (eg, 0.5) to ensure the decimal is seen but never after a decimal (eg, 5.0) because the decimal may be missed.
2. Understanding Formulation Differences & Availability
Veterinary nomenclature for suspensions and combination products can differ significantly from human medicine (Table). Veterinary product concentrations are often combined (eg, amoxicillin/clavulanate, trimethoprim/sulfamethoxazole), but human products are identified by the concentration of a single ingredient or the concentration of each ingredient separately, and the ratio of ingredients can vary. In addition, suspensions in human medicine are typically labeled with the concentration per teaspoon (ie, 5 mL) instead of per milliliter. Drug information resources should be referenced for product information when converting between human- and veterinary-labeled products.
Table: Examples of Nomenclature Differences of Commonly Prescribed Equivalent Medications
Although most drugs labeled for veterinary use are not available in community pharmacies, those that are available may be known by a different brand name or be similar to a different drug in human medicine, possibly leading to dispensing errors. For example, Zeniquin, the veterinary brand name for marbofloxacin, is similar to and can be confused with Sinequan, the human brand name for doxepin, especially because these medications are both available in 25 mg, 50 mg, and 100 mg forms. Prescriptions should be typed or clearly written, and generic drug names (with or without the brand name) should be used, particularly for veterinary-only products.6
3. Rechecking Dosages & Calculations
When administering medication in the clinic, veterinary staff are often familiar enough with a drug to recognize whether a dose seems unreasonably large or small for the size of the patient before giving the medication. Risk for dosage and calculation errors is increased in community pharmacies because of the lack of veterinary training and experience with veterinary drugs.
Dosage calculations for prescriptions that will be sent to a community pharmacy should be performed twice and reviewed by a second person. Decimals can be easily missed or misplaced, resulting in significant miscalculation (over or under) of the dose. Patient species and weight should be included on the prescription so pharmacists can calculate and verify the dosage with a veterinary reference.
4. Establishing a Relationship With a Local Pharmacy
Engaging with a community pharmacy not accustomed to working with veterinary patients can be challenging. These pharmacies typically request an NPI number, which identifies doctors for insurance billing in human medicine but is not legally available for veterinary clinicians, as prescriptions for animals cannot be billed to human insurance. In addition, veterinary drug dosages can be significantly higher than human dosages of the same product and may cause concern for the pharmacy. For example, an 88-lb (40-kg) dog could receive up to 400 mg of trazodone every 8 hours, whereas a human adult generally should not receive >400 mg every 24 hours.
Building a relationship with a local pharmacy can benefit the clinic and the pharmacy by creating an open line of communication, sharing information, avoiding repeated phone calls and stressful interactions, and increasing confidence that prescriptions are being filled correctly. Although pet owners may prefer a specific pharmacy, suggesting use of a location experienced with veterinary prescriptions may be helpful.
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Conclusion
Veterinary prescriptions filled by community pharmacies are likely to become more common as the price of medications increases and pet owners search for cost-effective options. Although risk for error is increased when prescriptions are sent to an outside pharmacy, clinicians can help pet owners manage budget concerns and maintain patient safety by using conscientious prescribing practices.
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