Physicians are being warned to pay close attention to how they prescribe oral methotrexate for the treatment of rheumatoid arthritis and other conditions in order to avoid fatal overdosing.

The Institute for Safe Medication Practices has reported cases of accidental daily administration of the drug where weekly dosing was intended with some cases resulting in death. Two such incidences have occurred within the past month, one resulting in death and the other in apparent permanent disability.

Mistakes in dosing methotrexate have been all too frequent because few medications are taken on a weekly basis and physicians and patients are much more familiar with daily drug dosages. Also, methotrexate is sometimes prescribed on a daily basis for oncology treatment with patients being properly monitored.

The Institute for Safe Medication Practices recommends the following safeguards to help reduce the risk of error when oral methotrexate is prescribed:

• Physicians should include a specific clinical indication (e.g. rheumatoid arthritis, psoriasis, etc.) within the prescription directions;
• Alerts should be built in to electronic prescribing systems and pharmacy computers to warn clinicians whenever oral methotrexate is entered so indication and dosing frequency can be assessed;
• If the purpose of the medication is not made apparent, pharmacists should speak directly to the prescribing physician to determine the reason for the use of the drug and verify the proper dosing schedule;
• A system should be established that ensures patients are given counseling when picking up new prescriptions and refills (e.g. mark the bag with a red flag to alert clerical staff that counseling is required versus optional);
• Pharmacists should always review prescription labels with the patient or caregiver to assure accuracy;
• Written drug information leaflets should be given to patients that contain clear advice about the weekly dosage schedule. Patients should have clearly written instructions that name a specific day of the week for taking the drug. The use of Monday should be avoided as it could be misread as "morning." Instructions should be easy to read for elderly patients;
• Patients should be warned that taking an extra dose of methotrexate could be dangerous and the drug should not be taken on an "as needed" basis; and
• Methotrexate should be prescribed and dispensed as a dose pack (e.g. Rheumatrex by Stada Pharmaceuticals) to help reinforce the weekly dosing schedule.

Other sources: Institute for Safe Medication Practices