(12-09-2009) Mistaken letters and numerals play a large part in errors when reading handwritten drug names and doses. Cursive writing is most susceptible to illegibility and carries the greatest vulnerability to error, as the various symbols often lack distinctiveness. A few examples of misinterpreted alphanumeric (letters and numerals) symbols that happened when reading handwritten medication orders follow.

·         A nurse misread an order for 2 mg of AMARYL (glimepiride) as 12 mg The lower case l at the end of the drug name, along with insufficient space between the last letter of the drug name and the dose, led the nurse to misread the dose as 12 mg.

·         While reviewing an order for a newly admitted patient, a pharmacist read "IODINE" in the space for allergies. Another pharmacist thought the allergy listed was LODINE (etodolac). The pharmacist contacted the patient's physician who identified Lodine as the actual allergy

Electronic medical records, medication administration records, and computerized prescriber order entry can help overcome many problems with handwritten information. However, even typed or computer-generated physician orders may not prevent confusion among certain alphanumeric symbols. For example, even a clearly typed prescription for 25 mcg of LEVOXYL (levothyroxine) could be misread as 125 mcg if it appears without proper spacing as Levoxyl25 mcg, especially since both strengths are available for this medication.

Research conducted by Bell Laboratories found that some symbols are more vulnerable than others to misidentification.The symbols l and 1, O and 0, Z and 2, and 1 and 7 accounted for more than 50% of the errors caused by symbol misidentification.

There are various ways to help cope with the inadequacies of alphanumeric symbols that are prone to confusion. Such as the following:

• Lower case letters or mixed case letters.
• Block printing on lightly lined forms
• Symbolic differentiation
• Space between the drug name and dose
• Drug and dose make sense

For more information on these strategies visit this link