Overview: Methotrexate, a high-alert medication, has been associated with an alarming number of wrong-frequency errors, the Institute for Safe Medication Practices (ISMP) warns. Overdoses have resulted in vomiting, serious skin lesions, liver failure, renal failure and death.
What you can do: ISMP suggests several preventive measures to avoid errors around medication reconciliation, transitions of care, misunderstood instructions and look-alike, sound-alike issues.
More needs to be done to prevent wrong-frequency errors involving oral methotrexate, according to a new alert from ISMP.
Originally approved to treat cancer, methotrexate is a folic acid antagonist that is also used for non-oncologic indications, such as psoriasis, rheumatoid arthritis, ectopic pregnancy and multiple sclerosis. Typically, patients receive a low dose once or twice weekly. But because weekly doses of any medication are unusual, accidental daily dosing of oral methotrexate occurs frequently.
The wrong-frequency errors originate at all stages of the medication use process, from prescribing to self-administration, and have resulted in vomiting, serious skin lesions, liver failure, renal failure and death.
6 ways to prevent methotrexate dosing errors
Most of the errors associated with methotrexate can be prevented by fully implementing the following, according to ISMP:
- Default to a weekly dosing schedule in prescriber and pharmacy order entry systems.
- Require verification and entry of an appropriate oncologic indication in order entry systems for daily orders.
- Educate patients and provide them with verbal and written instructions that specify the weekly dosing schedule and which emphasize the danger of taking daily or extra doses.
- Validate patients’ understanding by asking them to repeat back the instructions for taking oral methotrexate.
- Verify the dose and frequency of all medication lists and discharge instructions.
- Limit the prescription quantity to a 30-day supply (e.g., dispense just eight 2.5 mg tablets for a 5 mg weekly dose would reduce the risk of a serious overdose).