Methadone Dispensing: Learning from Recent Incidents

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In recent months, the College has received several complaints and reports related to medication incidents involving community pharmacies providing Methadone Maintenance Treatment (MMT). Many of these incidents involved a ten-fold increase in the dispensed dose compared to the intended prescribed dose. This is a significant risk to patient safety, with a high potential to cause harm due to overdose.

Upon analysis of these reports, some similar themes have been identified as potentially contributing to these errors. The information highlighted below is intended to be a learning opportunity for registrants to help prevent future incidents and reduce the risk of harm for patients.

  • Equipment limitations for low dose methadone prescriptions. For example, a dispensing pump system may have a minimum setting so a dose that is lower may be measured using an alternate, less accurate method of measurement.
  • Wide range of therapeutically appropriate doses. A pharmacist may not identify a large dose as a red flag as it could still be therapeutically valid, when it is actually ten times the intended dose. For example, the prescribed dose is 11 mg but the patient is dispensed 110 mg due to the amount being misread (e.g., a decimal is missed) and/or erroneously entered into the system.
  • Misinterpretation of the prescription. For example, if a prescriber states a volume for the dose and the pharmacist does not confirm the dose, it’s possible the prescriber is basing it on a concentration of 1mg/mL but the pharmacy dispenses the volume using the 10mg/mL solution. Alternately, if a prescriber states the dose in mg, the volume would have to be calculated based on the solution being used, and could be done incorrectly (e.g., 20mg using 10mg/mL = 2mL, not 20mL).
  • Pharmacists who are acting in a temporary or relief position at the pharmacy may not be familiar with MMT. They may also not be as aware of best practices and recommended doses for methadone dispensing and/or the policy and procedures of the individual pharmacy. The Designated Manager is responsible for ensuring all personnel are trained and competent.

Methadone Incidents Recorded in AIMS

Data from the Assurance and Improvement in Medication Safety (AIMS) Program also show that there have been 154 events related to methadone reported in 2022. Eighty-five per cent of the events reported were incidents, meaning that they reached the patient.

Sixty-one percent of the events reported in 2022 were categorized as either an incorrect quantity or an incorrect concentration.

Learnings for Pharmacy Professionals

Using the themes from the reports received directly by the College, and the anonymous data that can be analyzed from the AIMS Pharmapod platform, Designated Managers, pharmacists and pharmacy technicians who prepare and dispense methadone are expected to assess their own practice and identify any areas for improvement. This could include:

  • Creating, amending and/or reviewing written policies and procedures specifically to prevent issues that may arise with the dispensing of methadone and to ensure consistency. For example, the pharmacy can establish a procedure documenting the proper use of alternate equipment and the steps required to prepare accurate doses that are less than the current pump calibration.
  • Designing the dispensing workflow to allow for multiple checks to verify correct entry, dose preparation and labelling. For example, ensuring that the prescribed dose is written in the instructions for use as mg, not mL, and that the dose is appropriate based on a review of previous prescriptions. It is best practice to have two staff members independently verify the accuracy of a prescription regardless of the medication being dispensed but is particularly important with methadone as an error could lead to serious consequences, such as overdoses. Pharmacy professionals should also be aware of the possibility of confirmation bias (i.e., assuming that 90 mg is appropriate for this patient because 90 mg was a commonly dispensed dose that day).
  • Ensuring that every prescription has been assessed for therapeutic appropriateness prior to being dispensed and that standards of practice on patient assessment and documentation are met. As with all prescriptions, the pharmacy should develop a workflow whereby pharmacy staff (i.e., pharmacy technician, assistant) ensure a therapeutic check is completed by the pharmacist prior to releasing the medication. With methadone, a pharmacist must also do a clinical assessment of the patient prior to ingestion of the observed dose.
  • Verifying that staff have the necessary and up-to-date knowledge, skills and judgment to provide MMT before they engage in dispensing, particularly when those staff are providing temporary or relief coverage at the pharmacy. The College’s Opioid Policy requires that pharmacists providing opioid agonist treatment have the necessary knowledge and training. Staff should also be aware of the specific pharmacy’s policies and procedures related to methadone preparation and dispensing. As explained in the College’s Designated Manager – Professional Supervision of Pharmacy Personnel policy, Designated Managers must ensure that their staff are provided with the appropriate tools and resources to deliver safe and effective patient care.

The College’s Key Requirements for Methadone Maintenance Treatment (MMT) fact sheet outlines the necessary steps for a pharmacy to engage in MMT, including notifying OCP, obtaining required references, adhering to the Opioid Policy, ensuring staff are trained, developing policies and procedures and accounting for doses.

As with any prescription, medication incidents or near misses involving methadone must be recorded in the AIMS Pharmapod platform to enable proper analysis of the error and the development of learnings to share with staff, which may include changes to training, policies, procedures or equipment.

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Download the Methadone Dispensing Incidents: Contributing Factors, Key Learnings and Important Resources pdf


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