This column was prepared by the Institute for Safe Medication Practices (ISMP), an ECRI affiliate.

The Institute for Safe Medication Practices (ISMP) has received a report from an outpatient pharmacy regarding a close call with a product called InPen a Bluetooth-connected “smart” insulin pen system for mealtime insulins that is prescribed with either insulin aspart (NovoLog® or Fiasp®) or insulin lispro (Humalog®) U-100 cartridges.

Once the pen is loaded with the cartridge, InPen is used along with a smart phone app to interface with continuous glucose monitoring systems, remind patients to use their insulin, and log and track insulin doses. It can also administer half-unit doses.

The report indicates that an electronic prescription was received for “InPen (for Novolog or Fiasp) subcutaneous.” Shortly afterwards, a prescription for the same patient was received for three NovoLog U-100 3 mL cartridges. When a pharmacy technician went to the pharmacy’s wholesaler website, there were six different InPen devices listed, each with a description of their color (blue, gray, or pink). The technician incorrectly assumed that the pens differed by color. The pen labeled “InPen/blue/Lilly” was ordered, along with NovoLog cartridges. However, when the InPen arrived, pharmacists noticed a label on the product that stated, “For use with Humalog 3 mL U-100 insulin cartridges.”

Upon further investigation, it was found that of the six pens available there are only two different models of the InPen, and each model is available in three colors. One model is used with Humalog while the other model is for NovoLog or Fiasp. The models are not interchangeable due to the size differences between the respective insulin cartridges. The choice in colors appears to be for patient-preference and does not indicate which type of insulin is being used. Upon discovery of the error, the correct InPen device was ordered and replaced prior to dispensing the pen and insulin cartridges to the patient. It was noted by the reporter that the wholesaler’s information online regarding the InPen device was confusing and contributed to the ordering error. It is not clear why three different color pens are needed. This type of error would be less likely to occur if each model was one unique color.

Mitigation strategies include educating pharmacy staff on the availability and details of these new products, the packaging differences between NovoLog and Fiasp cartridges and Humalog cartridges; adding warnings in the computer system to alert pharmacy staff to verify that the InPen device selected is compatible with the patient’s insulin cartridges; and clearly naming each InPen in the computer system with the name of the insulin with which it is compatible. At the pharmacy counter, show the InPen and insulin cartridges to the patient and have both the patient and pharmacy staff person independently verify that the device and cartridge are compatible.

For more information on dispensing InPen devices and their specific national drug codes and compatibilities, visit: