The FDA notified healthcare providers and patients that insulin pens and insulin cartridges are never to be shared among patients. Sharing of insulin pens may result in transmission of hepatitis viruses, HIV, or other blood-borne pathogens. Insulin pens are not designed, and are not safe, for one pen to be used for more than one patient, even if needles are changed between patients because any blood contamination of the pen reservoir could result in transmission of already existing blood-borne pathogens from the previous user. The FDA is working with the Centers for Disease Control and Prevention, professional societies and healthcare organizations to reinforce patient and healthcare provider education about proper and safe use of insulin pens.

Source: U.S. Food and Drug Administration