Pharmacy Times

Mix-Ups Between Methylphenidate and Methadone Impact Children and Adults

Author: Michael J. Gaunt, PharmD

To prevent errors, health care professionals should consider the risk-reduction actions presented here.
A community pharmacy inadvertently dispensed methadone to a 7-year-old boy who normally takes methylphenidate 10 mg twice a day. The patient’s bottle was labeled as methylphenidate 10 mg. The boy’s mother gave the medication as prescribed, and the child became lethargic and vomited after taking 1 dose. The same symptoms developed again after giving the child the twice-daily dose the following day. The child was taken to a hospital emergency department (ED), and naloxone injection was administered. The child was admitted to a pediatric intensive care unit where he received a naloxone infusion and recovered.

ISMP and the FDA have received multiple reports of confusion between methadone and methylphenidate. In an earlier event, a 43-year-old patient received methadone 10 mg instead of methylphenidate 10 mg. The prescription was entered into the pharmacy computer system as methylphenidate with the correct strength, quantity, and directions, but a pharmacy technician accidentally pulled from the shelf a stock bottle of methadone, which was located in the space designated for methylphenidate. The technician then counted the tablets and placed the pharmacy-generated label on the prescription vial. The pharmacist performed a final check of the prescription and paid particular attention to the strength and dosage form to make sure the technician had not selected the sustained-release form of methylphenidate. However, confirmation bias allowed him to read the stock bottle as methylphenidate even though it was methadone and to dispense the prescription as filled. Despite noticing the tablets were larger than tablets she had previously taken, the patient took 2 doses, began not feeling well, and went to the ED, where she was observed for 4 hours. The dangerous mix-up between methadone and methylphenidate has also happened in hospitalized children on methylphenidate.

The risk of error is increased because of the shared “meth” prefix and overlapping tablet strength of 10 mg. Both drugs are also available from the same manufacturer and may be stored near each other or appear together on computer selection screens during e-prescribing or pharmacy order entry.

Safe Practice Recommendations

To prevent errors, health care professionals should consider the following risk-reduction actions:
Dr. Gaunt is a medication safety analyst and the editor of ISMP Medication Safety Alert! Community/Ambulatory Care Edition.