April 30, 2011: Muscle Relaxant Cyclobenzaprine Ordered as “Cycloprine” and Interpreted as Immunosuppressive Agent Cyclosporine
An order for “cycloprine 10 mg po qhs”, which was intended to refer to the muscle relaxant cyclobenzaprine, was entered into a pharmacy system as “cyclosporine 10 mg po qhs”. Fortunately, the error was caught, and cyclosporine was not dispensed.Cycloprine is not a generic drug name. The name of the generic drug cyclobenzaprine has been truncated to “cycloprine” in certain brand names (e.g., Riva–Cycloprine).
This term “cycloprine” resembles the drug name cyclosporine. Furthermore, cyclobenzaprine and cyclosporine are both available in a 10 mg dose form.
As noted above, cyclobenzaprine is a muscle relaxant, whereas cyclosporine is an immunosuppressive agent. As such, a mix–up between these 2 drugs could lead to patient harm. Although the incorrect medication did not reach the patient in the case summarized here, the incident became an important impetus for change. ISMP Canada contacted the manufacturers of generic cyclobenzaprine to seek their commitment to change any drug names containing the word “cycloprine”. One manufacturer, Laboratoire Riva Inc., was very receptive to the suggestion and is changing the name of its product. Teva Canada has changed the name of its product in the course of product rebranding (i.e., Novo–Cycloprine has been changed to Teva–Cyclobenzaprine). These newly renamed products will be available once existing stocks are depleted.
ISMP Canada reminds practitioners that removing the prefix (e.g., an abbreviated manufacturer’s name) from a brand name to identify the official generic medication name may not always work. During the course of this review, other brand names with truncated versions of the generic drug name were noted. ISMP Canada encourages all manufacturers to avoid using truncated versions of generic drug names within product brand names. As the incident described above illustrates, this practice can lead to confusion and unanticipated look–alike, sound–alike drug names.
