What are common medication errors pharmacists can make regarding drug mix-ups?

From the Guidelines

Pharmacists can make serious medication mix-ups, including confusing similarly named medications, dosage errors, label mix-ups, and formulation errors, which can be prevented with strategies such as barcode scanning, "tall man" lettering, and separate storage for look-alike medications. These mistakes can occur due to factors like cognitive overload, similar drug names or packaging, poor handwriting on prescriptions, and fatigue during long shifts 1. According to a study published in the British Journal of Pharmacology in 2009, inaccurate medication histories can lead to prescribing errors, such as duplication of drugs or unintended discontinuation of medications, with consequent unwanted interactions, failure to detect drug-related pathology, and loss of efficacy of established therapy 1.

Common Errors

Some common errors include:

• Confusing similarly named medications, such as hydroxyzine (for anxiety) with hydralazine (for blood pressure), or metformin (for diabetes) with metronidazole (an antibiotic)
• Dosage errors, such as dispensing 50mg instead of 5mg of warfarin, which could cause dangerous bleeding
• Label mix-ups, such as placing eye drop labels on ear drops or vice versa
• Formulation errors, such as dispensing extended-release versions when immediate-release is needed, dramatically altering how quickly medication takes effect

Prevention Strategies

Prevention strategies include:

• Using barcode scanning to verify medications
• Implementing "tall man" lettering to distinguish between similar drug names
• Maintaining adequate staffing to reduce cognitive overload and fatigue
• Utilizing separate storage for look-alike medications to prevent mix-ups
• Implementing IT systems to provide methods of avoiding medication errors, as recommended by a consensus meeting published in the British Journal of Pharmacology in 2009 1

Role of Pharmacists

Pharmacists play a vital role in optimizing medication treatment and preventing errors, as highlighted in a narrative review published in Thrombosis Research in 2023 1. They can review prescriptions, alert physicians to potential errors, and provide management options to ensure patient safety. The most effective way to prevent medication errors is to implement a combination of these strategies, including barcode scanning, "tall man" lettering, and separate storage for look-alike medications, as well as utilizing IT systems and pharmacist-led anticoagulant stewardship programs.

From the FDA Drug Label

Both the physician and pharmacist should emphasize to the patient that the recommended dose is taken weekly in rheumatoid arthritis and psoriasis, and that mistaken daily use of the recommended dose has led to fatal toxicity.

• Fatal toxicity can occur due to mistaken daily use of the recommended dose of methotrexate.
• Pharmacists should be aware of the potential for fatal toxicity when dispensing methotrexate and ensure that patients understand the correct dosing schedule.
• Mistaken daily use of methotrexate can lead to serious adverse effects, and pharmacists should take steps to prevent this, such as clearly labeling prescriptions and providing patient education 2.

From the Research

Medication Errors in Pharmacy Settings

• Medication errors can occur due to various factors, including incorrect dosing, administration route, or drug interactions 3, 4
• Double-checking high-risk medications can help reduce errors, and having two people verify the entire process can enhance safety 4
• Methotrexate toxicity is a significant concern, and errors in dosing or administration can lead to severe consequences 3, 5, 6

Methotrexate-Related Errors

• Methotrexate toxicity can be exacerbated by renal impairment, and incorrect dosing or administration can lead to increased toxicity risks 3
• Folinic acid is used to counteract methotrexate toxicity, but the required dosage differs for low-dose and high-dose methotrexate toxicities 3, 6
• Glucarpidase is a recombinant bacterial enzyme that can decrease serum methotrexate concentrations, but its use is limited by cost and availability 3

Preventing Medication Errors

• Double-checking medications, particularly high-risk ones like methotrexate, can help prevent errors 4
• Understanding the pharmacokinetics and pharmacodynamics of medications like methotrexate and folinic acid is crucial for safe administration 6
• Metformin has been shown to ameliorate methotrexate-induced genotoxicity in vitro, but further research is needed to confirm its clinical significance 7