Using the slashed zero to avoid discrepancies
Hospital pharmacy staff noticed a discrepancy with the lot numbers when repackaging enoxaparin injection by Amphastar Pharmaceuticals. The lot number printed on one label appeared to read "E0073G1," with two zeros after the letter "E." At the same time, another enoxaparin injection label from the same manufacturer clearly clearly read "E0O73G1" with a slashed zero, indicating that the second character is the letter "O" and the third character is the digit "zero," (see Lot number by comparison). This could be a safety issue in the event of a medication recall of enoxaparin injection, particularly those in packages with labels that don't clearly distinguish the letter "O" from the number "zero."
Using a slashed zero through it (O) helps make a clear distinction between "zero" ("0") and the Latin script letter "O." This strategy, which is used in other fields such as computer programming as well as in scientific and engineering applications, would be beneficial if widely adopted by drug companies.
Caution with look-alike tablets with nearly identical imprints
A pharmacist verifying a patient's medication from home discovered two brown, round tablets that had nearly identical imprints, "I 2" and "I-2," mixed in the same container. The pharmacist searched to know whether these look-alike tablets were the same medication, but found that they were different medications-amitriptyline and ibuprofen (see Look-alike tablets). The tablet with the "I 2" imprint was amitriptyline hydrochloride 25 mg, a tricyclic antidepressant; the tablet marked "I-2" was ibuprofen 200 mg.
Misidentification of these tablets could pose a critical safety issue. For example, an ED patient with a tricyclic antidepressant overdose-which is associated with severe cardiovascular, anticholinergic, and central nervous system adverse reactions-could be mistaken as overdosing on a nonsteroidal anti-inflammatory drug.
ISMP has reported this issue to the FDA. While the Code of Federal Regulations (CFR [S] 206.10) requires code imprints that, in conjunction with the product's size, shape, and color, permit the unique identification of the product, it does not mention specific instructions to make sure that solid oral dosage forms don't look too similar. ISMP has asked the FDA to determine whether the CFR requires modification. At one point, the United States Pharmacopeia (USP) explored the development and promotion of standardized imprint coding for solid oral dosage forms. USP members agreed that the current system for identifying oral dosage forms needed improvement. This effort was abandoned due to the cost considerations and uncertainty regarding the most optimal solution. Healthcare professionals and consumers can refer to resources like Medline-Plus Drugs, Herbs, and Supplements (http://www.ismp.org/ext/811) and DailyMed (http://www.ismp.org/ext/812) to learn more about container labels and package inserts for marketed drugs; however, these resources do not provide pill identification.