The GoodRx Prescription Savings Blog

The latest updates on prescription drugs and ways to save from the GoodRx medical team

Diabeta vs Micronase: What’s the Difference?

by The GoodRx Pharmacist on February 6, 2014 at 3:12 pm

As you may already know, there are two different forms of glyburide, regular nonmicronized glyburide (Micronase, Diabeta) and micronized glyburide (Glynase) that can’t be substituted for each other. So, what about Diabeta and Micronase? Both have glyburide as an active ingredient, both are used type 2 diabetes to improve glycemic control and lower blood sugar levels, and they come in the same dosages—however, they also can’t be substituted for each other.

Is Diabeta therapeutically equivalent to Micronase?

No. As a matter of fact, although they may share glyburide as an active ingredient, Diabeta is not equivalent to any other medication available. It is BX rated by the FDA to all other glyburide products.

What does a BX rating mean?

Per the FDA:

The code BX is assigned to specific drug products for which the data that have been reviewed by the Agency are insufficient to determine therapeutic equivalence . . . In these situations, the drug products are presumed to be therapeutically inequivalent until the Agency has determined that there is adequate information to make a full evaluation of therapeutic equivalence.

Often the problem is with specific dosage forms rather than with the active ingredients.

So, there may not be specific evidence that Diabeta is not equivalent to other glyburide medications, but there isn’t enough evidence to prove that it is equivalent. It may be that the dosages or forms of Diabeta are not similar enough, rather than a difference in the active ingredient.

Can generic glyburide be substituted for Diabeta?

No. Diabeta does not have a generic glyburide counterpart. If your doctor writes a prescription for Diabeta, it MUST be dispensed as Diabeta.

Can a generic glyburide be substituted for Micronase?

Yes. Generic glyburide can be substituted for Micronase; they are equivalent. The exception would be micronized glyburide, which is equivalent to Glynase instead.

Can Diabeta and Micronase be substituted for one another?

No. Here’s where it gets a little complicated. Even though the generic for both Diabeta and Micronase is glyburide, they have not been deemed therapeutically equivalent by the FDA. Diabeta, Micronase, and generic glyburide also cannot be substituted for Glynase or micronized glyburide.


I attempted to contact the company that makes Diabeta, Sanofi-Aventis, regarding the exact reason why the medication is not rated as equivalent to other glyburide products. However, they could not give me the exact reason. They said it is an older drug from 1984 that they inherited from another pharmaceutical company, Hoechst.

Check out this article for more insight into this glyburide debacle.

As it stands no one can really explain the exact reason of its therapeutic inequivalence to the generics just that Diabeta CANNOT be substituted.

Copyright ©2015 GoodRx, Inc.

This information is for informational purposes only and is not meant to be a substitute for professional medical advice, diagnosis or treatment. GoodRx is not offering advice, recommending or endorsing any specific prescription drug, pharmacy or other information on the site. GoodRx provides no warranty for any of the pricing data or other information. Please seek medical advice before starting, changing or terminating any medical treatment. Third party logos, trademarks, brand names and images contained on are for demonstration purposes only and are owned by their respective rights holders, who are not affiliated with this Site.