Patient harm from taking methotrexate daily after wrong-drug error
Institute for Safe Medication Practices, Horsham, PA
A patient recently reported that they had been inadvertently taking 2.5 mg of methotrexate—an antineoplastic and immunosuppressant agent—daily for nearly 3 months instead of 10 mg of prasugrel, an antiplatelet agent that had been prescribed.
A community pharmacy dispensed the incorrect drug after applying the patient’s prasugrel prescription label to a manufacturer bottle of methotrexate. The patient experienced worsening adverse effects from the methotrexate, including arm and joint pain and hair loss. At the time of the report, the patient was still not feeling well.
Thankfully, the patient appears to have managed to avoid the serious harm (e.g., stomatitis, liver failure, renal failure, myelosuppression, GI bleeding, life-threatening pulmonary symptoms, and death) that other patients have suffered when methotrexate was inadvertently taken daily.
Also, the patient did not experience a thrombotic cardiovascular event despite not taking the prescribed prasugrel for 3 months.
While we do not know the details of how the error occurred, the patient indicated that the methotrexate bottle looked like the prasugrel bottle they routinely received. For example, Mylan uses unique blue-colored bottles for their medications, which may contribute to look-alike similarities. It is also plausible that the pharmacy staff was working on prescriptions for more than one patient at a time, increasing the risk of errors as manufacturer containers, pharmacy containers, and pharmacy labels could easily be mixed-up. Another possibility is that the methotrexate bottle was on the pharmacy counter because it was pulled in anticipation of using it for a different patient’s prescription.
What we do know is that despite the patient reporting this event to the pharmacy, they have only received a message stating that a district manager would be in contact. To prevent this type of error, it is critical that pharmacy staff generate prescription labels for one patient at a time and then fill that patient’s prescription(s) to avoid affixing the wrong label to a bottle of medication intended for another patient. Baskets or trays can be used to keep labeled containers, stock bottles, and documentation for one patient together until final verification.
When affixing the pharmacy label to a manufacturer’s container, avoid covering critical information, including the drug name and strength. Return unused or partially used medication bottles to the pharmacy shelves as quickly as possible to reduce the potential for wrong-drug errors. If you encounter look-alike containers, investigate ordering one of the containers from a different manufacturer.
If not already done, install and use barcode verification during production. Scan each package or container (e.g., bottle, carton) used to fill a prescription, including each manufacturer carton or bottle that may be dispensed to a patient. Standardized processes should be developed to guide the pharmacist’s final verification of a medication.
At the point-of-sale, have the patient review the pharmacy labels and contents of each prescription container to check that the medication is correct, even if this requires opening the bag. When a patient reports a potential or actual error, respond to the patient in a timely manner with transparency and honesty.
The goal is to correct the error, minimize any harm or negative impact to the patient, and work to regain their trust in the system. ■