Look-alike, Soundalike Drugs: Why Confusion Happens and How Health Systems Can Prevent It

Look-alike, soundalike (LASA) medications are easily confused due to visual similarities in packaging, dosages, or phonetically similar nomenclature. These are responsible for approximately 6.2% to 14.7% of all medication errors.¹ LASA medication errors can occur in any health care setting, and can result in serious, potentially fatal consequences to patients.

Contributing Factors

Medication errors resulting from LASA medications are rarely the result of a single oversight. They stem from a combination of factors that come together during medication management.

Linguistic and Nomenclature Challenges

Orthographic similarity, the extent to which 2 words or strings of text resemble one another in their written form (eg, hydroxyzine vs hydralazine), can be especially dangerous if they have similar prefixes and/or suffixes.

Phonetically similar drug names (eg, Celexa vs Zyprexa) can be confused and lead to errors during verbal orders, particularly in noisy, high-stress environments like pharmacies.

The constant addition of new brand and generic names in the pharmacy field increases the risk of unfamiliarity with LASA medications. With thousands of existing medications, it is ever more difficult to name new drugs without creating more LASA medications.

Packaging and Visual Design Issues

Manufacturing companies often use a standardized commercial look for their products, leading to different drugs having the same or similar container size, cap colors, and label layouts.

Medication labels can be poorly designed, with small fonts, insufficient contrast, and important information placed in inconvenient locations, which can contribute to “grab-and-go” errors.

Similar delivery forms, such as vials of injectable medications, may look the same except for drug concentration or drug name. This is especially concerning in fast-paced settings such as anesthesia.²

Supply Chain and Operational Pressures

Drug shortages can force pharmacies to change manufacturers, purchase different strengths, or borrow from other pharmacies. This introduces unfamiliar packaging and new concentrations, which can add to LASA risks.³

Substitution risks arise when a preferred drug is unavailable, and the use of alternatives, often in different strengths, is required. This use of alternative drugs, dosage forms, or dosage strengths can account for harmful outcomes related to drug shortages.⁴

Although “just-in-time” inventory practices are beneficial to the bottom line, if a familiar product is substituted with a visually similar but different drug, the lack of backup stock prevents an easy double-check.

Environmental and Human Factors

When processing written words, humans read in “chunks.” This refers to breaking text down into small, manageable units. Therefore, similar beginnings or endings in drug names allow the human brain to fill in the rest of the word based on expectations.⁵

Workplace stressors such as heavy workloads, long shifts, and burnout reduce the cognitive bandwidth needed to apply detailed attention to filling prescriptions.

Frequent distractions and interruptions during prescription processing are leading contributors to anticipatory errors, selecting a drug that is expected rather than what is present.⁶

Technological and System Failures

Electronic health records that use alphabetical drug drop-down menus increase the risk of LASA drug selection errors. The wrong medication may be selected based on its proximity to its LASA counterpart.

Prescription processing systems that lack barcode verification or have insufficient alerts fail to provide the necessary elements to intercept manual errors.

Safety Strategies and Preventive Measures

Best practices for managing LASA medications incorporate behavioral changes, strict nomenclature standards, and advanced technological safeguards to reduce the risk of medication errors.

Tall-Man Lettering

Use of mixed-case or tall-man lettering, such as vinBLAStine vs vinCRIStine, is recommended on all electronic prescribing screens, automated dispensing cabinet displays, and smart infusion pump libraries.⁷

Brand/Generic Dual Listing

Systems are now configured to display brand and generic names for high-risk LASA medications to provide an additional point of verification.

Visual Aids

Many organizations incorporate bold fonts, color-coded highlighting, and auxiliary labels to differentiate drug names and strengths on shelves and/or automated dispensing cabinets.

Barcoding/Scanning

Best practices recommend the use of barcode medication administration during every stage of the medication administration process, including inventory restocking, pharmacy dispensing, and final patient administration.⁸

Enhanced Search Protocols

To decrease the risk of selecting similar-sounding medications from drop-down menus, digital systems often require a minimum of 5 letters during a drug search.⁹

Clinical Decision Support

Clinical decision support systems often contain tools that trigger alerts when high-risk LASA medications are selected, requiring providers to confirm the drug choice against the patient’s diagnosis.

Physical Segregation

Physical separation of high-risk LASA medications can be achieved by using different physical spaces or storage mechanisms; for example, storing one of the pair on the shelf and the other in a closed container.

Indication-Based Prescribing

Adding the indication to all prescriptions allows for additional verification that the drug aligns with the patient’s condition.

Standardized Concentrations

Limiting the available concentrations of high-alert injectable and liquid medications reduces the risk of selecting the wrong strength.¹⁰

Conclusion

The challenge of LASA medications remains complex, involving linguistic hurdles, manufacturing specifications, and human cognition. With the constant addition of new medications, confusion persists, placing patient safety at risk. Mitigation of LASA risks requires a multifaceted approach that integrates sophisticated tools to intercept errors before they reach the patient.

By combining standardized nomenclature, like tall-man lettering, with physical safeguards, such as physical segregation, and technological precautions, such as barcoding, organizations can build systems resilient to human error.

Ultimately, a culture of safety prioritizing transparency, continuous education, and patient advocacy is crucial. The goal is to shift from a reactive to a proactive approach, where medication systems are designed to guide practitioners to the correct product.

REFERENCES

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