# Botulinum Toxin Type A Reconstituted with Lidocaine: A Report of 1000 Consecutive Cases
## 4 Discussion  
Botulinum toxin is a fascinating drug that specifically targets the release of acetylcholine. Acetylcholine is a common neural transmitter that stimulates striated as well as smooth muscles and the secretion of glands such as sweat glands. After BoNTA is ingested or injected, it diffuses into the human tissue until it selectively and irreversibly binds to the presynaptic terminal of the neuromuscular or neuroglandular junction, where it exerts its actions by cleaving specific membrane proteins responsible for acetylcholine secretion [11]. Dr. [PERSON], in the 1980s, was the first to use botulinum toxin clinically with research on strabismus and blepharospasm after using it successfully in experiments on monkeys  
Figure 4: Case 2. Two minutes after the injections of BoNTA reconstituted with lidocaine for the treatment of forehead wrinkles. Figure 3: Case 2. A 33-year-old woman before the injections of BoNTA reconstituted with lidocaine for the treatment of forehead wrinkles. in the 1970s [16]. Today, BoNTA is used to treat many medical conditions, especially last year's larger dilution (microbotox) of the toxin, which has been proposed to treat several dermatological problems such as oily skin, scarring, rosacea, etc. [17]. The first study indicating the utility of BoNTA for the treatment of hyperfunctional facial lines occurred in the early 1990s by [PERSON] and [PERSON] [18]; during the following years, aesthetic indications and the safety of this procedure have been widely shown [19; 20; 21]. Over the past two decades, its use worldwide has transformed the aesthetic care of the aging face. Since the U.S.'s introduction of onabotulinumtoxinA in 2003 for the treatment of glabellar lines, the injection of BoNTA has become the most common aesthetic procedure performed in the United States [8]. Off-label clinical indications include hyperfunctional facial lines on the bridge of the nose, masseter and temporalis muscles hypertrophy, \"golf ball chin\", gummy smiles, platysmal banding, etc. [10; 22; 23; 24]. In facial cosmetics, the goal of BoNTA treatment is weakening a mimetic muscle to either reduce its wrinkling effect on the skin or alter the position of a nearby facial feature (e.g., brow contour). BoNTA is sold in vials in a lyophilized form that must be reconstituted; the reconstitution recommendation is to add 1.25 mL of saline solution in the case of onabotulinum or incobotulinum toxin A [25] and just 0.63 or 1.25 mL is required to reconstitute abobotulinum toxin A [26]. However, in the medical literature, different dilutions have been proposed and evidence shows no difference in the use of BoNTA in aesthetic indications at different dilutions [27]. Few studies have furthermore compared the use of preserved vs. non-preserved saline for reconstitution. Evidence suggests less pain is experienced by the patient while the BoNTA effects are not compromised [27]. For many years, several studies have tried to show one toxin to be superior to others, although it is almost impossible to compare the same drug in different patients using fixed doses at fixed positions of the face [28]. For example, some studies suggested onabotulinum is superior to abobotulinum: in a pilot study, 20 U of onabotulinum provided better and more prolonged efficacy than 50 U of abobotulinum for glabellar lines, as assessed by a blinded investigator; although the effect of onabotulinum apparently increased over time in the study, it was not seen in any other study or clinical practice [13]. Certain studies suggested the converse, that abobotulinum is superior to onabotulinum. [PERSON] et al. reported that abobotulinum \(\backslash\) m (256 U total) was significantly more effective than onabotulinum (64 U total) for upper facial lines. These differences may reflect a higher abobotulinum dose than in the studies that suggest onabotulinum to be superior to abobotulinum [29]. Certain authors have suggested that protein load may influence diffusion. [PERSON] et al.