Neuromodulators not equal

Joel Cohen, M.D., explained to attendees at MauiDerm 2014 the differences among the three approved botulinum toxin products and how to use them successfully to take advantage of their unique properties. He recommended that doctors really think about these products as unique and begin to use them for their individual properties. They’re not interchangeable, he said. Conversion factors are inadequate, studies have found, so there's no perfect conversion ratio. And it's very difficult to make direct comparisons between products because studies have been designed differently, there has been an evolution of endpoints  and study design may lead to limitations in how you are able to interpret the data.

In comparing studies, clinicians run into challenges in that endpoints are changing. The Food and Drug Administration now requires a two-grade composite improvement in which both the physician and the patient agree there is a two-grade improvement.

So there are different criteria being used, according to Dr. Cohen, director of AboutSkin Dermatology and DermSurgery, Englewood Colo. Also, there are differences in technique between what is used in FDA pivotal studies and what physicians probably do in their practices, he said. Often the studies stick to very specific dosing, but in a medical practice, a study dose may not be warranted for a particular patient. Dr. Cohen said he tapers according to the patient’s musculature.

When it comes to combination therapy, Dr. Cohen advised avoiding multiple modalities in the same day because side effects of one treatment may impact the results of another. He offered an example of a patient who received one injection of a neuromodulator in the mentalis as well as a trichloroacetic acid peel. Swelling from the peel resulted in migration of the neuromodulator, which knocked out the depressor anguli oris.

Dr. Cohen cautioned against combining products in one syringe, as one pilot study examined. There’s likely a lack of standardization in the reconstitution process, and this could lead to unwanted effects.

There is good data on combination therapies on different days, however. Dr. Cohen pointed to a study in which patients were treated with onabotulinumtoxinA in the glabellar, and then returned for treatment with hyaluronic acid (Restylane). Compared to a group of patients only treated with onabotulinumtoxinA, results in the combination group lasted about 32 weeks longer. Combination therapies can be very effective, he said.

Your approach to each patient should be different, Dr. Cohen said. He noted the anatomic differences between men and woman, particularly in the upper face and forehead, as shown in another study. Treating by region for a specific goal, rather than by a standardized treatment protocol, is how Dr. Cohen likes to approach aesthetics, he said.

When used properly, studies have shown that neuromodulators can improve a person’s quality of life through improved self-esteem. Educating yourself on the properties of the individual products, the data and then using that information to make educated decisions in how you approach your practice can make for successful outcomes.