How to Differentiate Between Look-Alike Sound-Alike Drugs

A new study reveals that drug indications data from a drug knowledge base can differentiate between many look-alike-sound-alike (LASA) drugs that are easily confused. The finding may add impetus to the push to add indications to prescriptions.

“It can be easy to confuse two LASA drugs. Having the indication for a drug can help pharmacists recognize potential LASA drug errors, particularly if the indications for two LASA drugs are very different,” says Christine Cheng, PharmD, lead author of the study.

Related article: ISMP Issues Alert, Urges Pharmacist Intervention

Cheng, a clinical pharmacist in the Disease Decision Support Group at First Databank Inc., says the study sought to determine to what extent LASA drugs on the Institute for Safe Medication Practices’ (ISMP) list of easily confused drug names could be differentiated by high-level/general indications from a commercial knowledge base. A knowledge base is an advanced type of database.

Results of the study were published in the May 2018 issue of the Journal of the American Medical Informatics Association. Cheng says that the study used ISMP’s list of easily confused drugs names as its list of LASA drugs. The source for indications was a commercial knowledge base (First Databank MedKnowledge Indications Module) that includes both FDA-approved and off-label indications for drugs.

The study excluded certain drugs from the ISMP list. For example: drugs no longer marketed or not marketed in the United States, medical supplies, medical devices, and dietary supplements. It evaluated 278 pairs of drugs with LASA names involving 452 unique drugs. There were 165 (59%) LASA pairs with no overlap in high-level indications, 58 (21%) LASA drug pairs with partial overlap, and 55 (20%) LASA drug pairs with complete overlap.

“This means that the majority of LASA drug pairs on the ISMP list could be differentiated with even high-level general indications. Had we used more granular indications, we likely would have been able to differentiate even more LASA pairs.

Patient Safety

Cheng said if pharmacists and physicians know what the purpose of the drug, it’s easier to see if the dosing is right, if it’s the right regimen, and if the patient carries the correct diagnosis.

Related article: The Case for Indications on Prescriptions

She added that it’s a good idea for pharmacists to confirm that the patient knows the purpose for each of the drugs they’re taking. “It’s empowering them to know they’re taking each of their medications and to ask questions.”