Metformin HCl ER – Audit Considerations

Metformin HCl ER is indicated as an adjunct to diet and exercise to improve glycemic control in adults with type 2 diabetes mellitus. It is commonly prescribed for patients who have gastrointestinal side-effects when taking the original. non-ER. version of the medication. Unfortunately, the cost difference can be significant, leading to an increased risk for audit – especially when a patient is taking Glumetza® or Fortamet®.

To add to the confusion, there are three different versions of metformin HCl ER, with three different extended-release mechanisms.

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They are not interchangeable with one another and, consequently, have unique Therapeutic Equivalency (TE) codes to show which generic products can be substituted for a specific brand name. When there are multiple branded versions of an identical active drug ingredient, form, and route of administration, then the FDA must assign each brand an additional identifier such as AB, AB1, AB2 and AB3.

Brand Name Strengths (mg) FDA Orange Book TE Codes Extended-Release Format
Glucophage® XR 500, 750 AB, AB1 Dual hydrophilic polymer system
Fortamet® 500, 1000 AB2 Single-Composition Osmotic Technology (SCOT)
Glumetza® 500, 1000 AB3 Gastric Retention Technology

You may only dispense a generic formulation of the above if the TE code matches.

PAAS Tips:

  • Dispensing higher cost medications when lower cost alternatives are available is a red flag for PBMs and can lead to increased scrutiny
  • Auditors may require clarification from the prescriber when dispensing these higher cost medications
  • If switching a patient from metformin HCl to metformin HCl ER for clinical reasons, including side effects, document the rationale on the prescription
  • Switching a majority of your patients on metformin HCl to metformin HCl ER can also be a red flag for auditors
  • This could lead to accusations of solicitation and possible contract termination
  • Prescriptions written for generic metformin HCl ER should be clarified with the prescriber as to which version is preferred and make a clinical note on the prescription
  • Clinical notes should contain the date of the call, the name AND title of who you spoke with, what was discussed, and your initials
  • If substitution is required between versions that do not have the same TE code (e.g., Fortamet® to Glumetza®/AB2 to AB3), you will need to obtain prescriber approval and make a clinical note on the prescription
  • Prescriber approval is required even if the plan requires one formulation over another
  • TE codes can be identified by using the FDA Orange Book

Jenevra Azzopardi, CPhT
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