If you have been in practice long enough, you have likely seen patients make dosing errors because they misunderstood something. Some are understandable, others may be surprising. For instance, would you suspect that a patient or caregiver would intentionally use a syringe to withdraw insulin from an insulin pen and then administer a dose from that syringe?
The practice may seem counterintuitive in the sense that the pen should eliminate, rather than encourage, the patient’s or caregiver’s need or desire to draw a dose with a syringe. However, the FDA received 138 cases between January 2012 and May 2017 submitted to the agency’s Adverse Event Reporting System that describe withdrawal of insulin from prefilled pens using U-100 insulin syringes, sometimes with serious consequences. However, keep in mind that the number of reports we receive does not project the error’s prevalence, as errors often go unreported.
Extracting a dose from a pen into a syringe has been reported with several brands of insulin-containing pens. So, this is not a product-specific issue. This practice can result in dangerous overdoses of insulin, particularly if a syringe calibrated for U-100 insulin is used to dose a concentrated insulin (U-200, U-300 or U-500 insulin, for example), which are often available as prefilled pens.
Why would a patient or caregiver do this? The error reports we have received at FDA indicate multiple reasons, but the most common include difficulty using the device, user preference or the lack of pen needles. For example, one report indicated that the patient’s visual problems made use of a pen difficult so the caregiver withdrew the doses into a syringe for the patient. As this patient was using concentrated insulin, she received three times the intended dose before the error was caught.
A lack of pen needles is a fixable problem. When prescribing insulin pens, make sure the patient or caregiver knows that they will also need to obtain pen needles and must have an ample supply. Insulin pens are not supplied with pen needles in the carton, so they must be purchased separately. In addition, some states require a separate prescription for the needles.
Prescribing insulin pens offers important patient education opportunities:
- Remind patients that using a syringe to draw medicine from an insulin pen is an unsafe practice. Advise them to contact their health care provider or the product manufacturer if they have trouble using the pen.
- Remind patients or caregivers to always use a new needle for each dose and to never share their insulin pens with other people. Shared pens can spread infections, even if the pen needle has been changed.
FDA does not currently have safety concerns specific to a particular prefilled insulin pen. However, we acknowledge that the risk for serious consequences associated with this error are higher with concentrated insulins. FDA will continue to monitor safety reports for this dosing error. Prescribers are uniquely qualified to help patients avoid this potentially dangerous behavior by counseling patients and providing needles intended to be used with insulin pens. Working together we can protect public health and enhance patient care.
- For more information:
Hina Mehta, PharmD, is team leader in the Division of Medication Error Prevention and Analysis, Office of Surveillance and Epidemiology, Office of Medication Error Prevention and Risk Analysis at the FDA.
Ariane O. Conrad, PharmD, BCACP, CDE, FISMP, is a safety evaluator in the Division of Medication Error Prevention and Analysis, Office of Surveillance and Epidemiology, Office of Medication Error Prevention and Risk Analysis at the FDA.
Disclosures: Conrad and Mehta report no relevant financial disclosures.