Spring 2022 • Vol 42 • Issue 2
COMPARISON OF BOTULINUM TOXINS
PRESENTED BY JURIJ BILYK, MD • REPORTED BY CYNTHIA CLARK Symposium Program Director, Dr. Jurij Bilyk, discussed the three FDA-approved Botulinum Toxin’s (BoNTs)—Allergan’s Botox®, Merz’s Xeomin®, and Galderma & Ipsen’s Dysport®. As Dr. Bilyk stated in his opening, “Some things are worth hearing a couple of times, especially in medicine.” He pointed out that Juij Bilyk, MD blepharospasm has a spectrum of symptoms, from pure spasming to a combination of spasms and apraxia to pure apraxia. It seems illogical that BoNT would work on apraxia – where someone simply can’t open their eyes – but it does. Further, some people’s frustration with botulinum toxin may not be the ‘spasm’ part, but rather the ‘apraxia’ part. His purpose was to clarify how BoNTs work in the nervous system and why it is the most beneficial treatment, as well as pluses and minuses and side effects. To help us understand how BoNTs work, Dr. Bilyk used his slides to clearly explain the nerve connections and how fragile these connections are. He stated that these toxins have an affinity for hyperactive nerve terminals, which is what typifies dystonia including BEB. After injections it usually takes a couple of days for the effects to kick-in and will last from two to five months. He went on to explain that it is important for patients to understand the two stages of recovery after this initial injection with a primary effect on what he termed “nerve
sprouting” and the secondary effect when the BoNT moves into the main nerve. All FDA-approved BoNTs work this way with minimal variability. Additionally, he stressed that more frequent injections may not be the answer since the body doesn’t have time to recover. In other words, these nerve terminals are not ready to be blocked again. The BoNT has within its structure heavy and light chains that are attached by a very fragile disulfide bond that is crucial to toxin efficacy. This bond is susceptible to environmental factors such as temperature. He explained how BoNT works on and within nerves – see the slide illustration. Next, Dr. Bilyk explained the variables involved for physicians with available choices of BoNTs— including: the chemistry variants among the different types of BoNT, the “other stuff in the bottle,” the preparations or amounts of units and storage before and after preparation, and indications depending on all the variations of patients. These patient variations include geographic distribution—some areas do not have access to all approved BoNTs; and some insurance companies refuse one type to another. A final variable is the anatomy of each patient—muscle activity or pattern of spasm; muscle architecture; thickness of epidermis and skin, fascial planes and eyelid anatomical planes and just plain AGE. Dr. Bilyk explained that older patients may need less due to loss of muscle mass; therefore, less toxin may be needed. Another consideration for the variables of BoNT include injection techniques: dilution of doses, volumes of injection, CONTINUED ON PAGE 4
