Serious and long-term adverse events associated with the therapeutic and cosmetic use of botulinum toxin

Non-cosmetic use of botulinum toxin in surgical conditions

Botulinum toxin (BTX) is a neurotoxin that has an ability to create a fully reversible relaxation of muscles through decreased release of acethylcholin. It also has an effect on the cholinergic autoimmune nervous system, and it can reduce pain sensitization. BTX is widely used in cosmetic treatments. In recent years, BTX has increasingly been used to treat several medical and surgical conditions. In many cases, this is despite weak evidence and without approval from the European Medicine Agency (EMA). This narrative review describes how BTX is used in the different surgical specialties and provides a brief overview of the use of BTX for non-cosmetic surgical conditions.

Patient Characteristics and Real-World Use of Botulinum Toxins for the Treatment of Cervical Dystonia, Blepharospasm, and Hemifacial Spasm

Movement disorders such as cervical dystonia, blepharospasm, and hemifacial spasm negatively impact the quality of life of people living with these conditions. Botulinum toxin (BoNT) injections are commonly used to treat these disorders. We sought to describe patient characteristics, BoNT utilization, and potential adverse events (AEs) among patients with cervical dystonia, blepharospasm, and hemifacial spasm using Optum's de-identified Clinformatics® Data Mart Database. Patients were required to have a diagnosis of the specific condition plus evidence of treatment with BoNT between 8/1/2010 and 5/31/2022. Cervical dystonia patients were commonly females (76%) and aged 45 and older (78%); both blepharospasm and hemifacial spasm patients were commonly females (both 69%) and aged 65 and older (61% and 56%, respectively). Anticholinergics were commonly used (65-82% across cohorts), as were peripheral muscle relaxants for cervical dystonia patients specifically (31%). The median number of injections per year was 2 with the median weeks between injections being between 13 and 15. Of the AEs evaluated, dyspnea was identified frequently across all the cohorts (14-20%). The findings were similar for different BoNT formulations. More research is needed to thoroughly describe BoNT utilization, such as the doses injected, and to optimize treatment for patients with these conditions.

Ultrasound-Guided Botulinum Neurotoxin Injection for Alleviating Cricopharyngeus Muscle Spasticity: A Cadaveric Feasibility Study with Nerve Ending Analysis

Botulinum neurotoxin (BNT) injection into the cricopharyngeus muscle (CPM) under ultrasound (US) guidance is a minimally invasive technique performed to relieve cricopharyngeal dysphagia by reducing CPM spasticity. This technique is basically accessible only to both lateral sides of the CPM. This cadaveric study aimed to evaluate whether US-guided injection could effectively deliver BNT to abundant areas of gross nerve endings within the CPM. We utilized a newly modified Sihler's staining method to identify regions with abundant neural endings within the CPM while preserving the three-dimensional morphology of the muscle in 10 sides of 5 fresh cadavers. A mixture of 0.2 mL dye was injected into the 16 sides of CPM under US guidance in 8 cadavers. Nerve endings were abundant in posterolateral areas of the CPM; the injected dye was identified at the posterolateral area on 12 sides (12/16 side, 75%) without diffusion into the posterior cricoarytenoid muscle. The injection failed on four sides (two sides of the prevertebral fascia and two sides of the esophagus below the CPM). These results suggest that US-guided injection could be a feasible technique as it can deliver BNT to the most abundant nerve distribution areas within the CPM in most cases.

Botulinum toxin A versus microwave thermolysis for primary axillary hyperhidrosis: A randomized controlled trial

Background

Botulinum toxin A (BTX) and microwave thermolysis (MWT) represent 2 treatment modalities for axillary hyperhidrosis with different procedural and efficacy profiles.

Objective

To compare long-term outcomes following BTX vs MWT treatment of axillary hyperhidrosis.

Methods

A prospective, randomized, within-patient, controlled trial, treating axillary hyperhidrosis with contralateral BTX and MWT. Objective sweat measurement and patient-reported outcome measures for sweat and odor were collected at baseline, 6-month and 1-year follow-up (6M/1YFU). Hair reduction and patient treatment preference was also assessed.

Results

Sweat reduction was significant (all P <.01) for both interventions throughout the study. Objectively, sweat reduction was equal at 1-year FU (ΔP =.4282), but greater for BTX than MWT at 6-month FU (ΔP =.0053). Subjective sweat assessment presented comparable efficacy (6MFU: ΔP =.4142, 1YFU: ΔP =.1025). Odor reduction was significant (all P <.01) following both interventions, whereas only sustaining for MWT (6MFU: ΔP =.6826, 1YFU: ΔP =.0098). Long-term, hair reduction was visible after MWT, but not BTX (ΔP ≤.0001), and MWT was preferred by the majority of patients (76%).

Limitations

The intrinsic challenges in efficacy assessment.

Conclusion

This study exhibited BTX and MWT with similar sweat reduction, but distinguishable odor and hair reduction at 1-year FU. These findings support individualized treatment approaches for axillary hyperhidrosis based on patient-specific symptoms and preferences.

High-Resolution Ultrasound for Complications of Botulinum Toxin Use: A Case Series and Literature Review

Botulinum toxin (BTX) has revolutionized both aesthetic and therapeutic medicine by selectively inhibiting acetylcholine release at the neuromuscular junction, inducing localized muscle relaxation. However, its use can be associated with various complications. As a diagnostic modality, high-resolution ultrasound can better characterize these complications. Here, we present four clinical cases of complications associated with the application of BTX, along with their corresponding ultrasonographic findings. In this study, cases were selected randomly, irrespective of the timing of BTX injections, to illustrate a spectrum of complications observed in clinical practice. Despite its benefits, BTX can have adverse effects ranging from mild to severe, including aesthetic and functional complications, such as hematoma, ptosis, facial asymmetry, nodules, or pseudoaneurysm. High-resolution ultrasound emerges as a crucial tool in the multidisciplinary management of these complications, allowing for accurate evaluation and effective therapeutic guidance.

Facial Painting and 3D Stereophotogrammetric Analysis of Facial Dynamics: A Reliable Anatomical Educational Method

(1) Background: Accurate knowledge of the dynamic anatomy of facial muscles is crucial for the use of functional and aesthetic botulinum toxin injections. We studied the reliability and relevance of facial painting as a pedagogic tool for the dynamic anatomy of facial muscles. (2) Methods: Different facial expressions were performed by a female model after a professional makeup artist applied makeup to the various facial muscles on her left hemiface. A 3D photograph was taken at the beginning and end of each movement using the VECTRA H2 Imaging System device. Cutaneous movements were visualized using displacement vectors. The correlation between the theoretical and dynamic positions of the makeup-muscle was assessed by two facial anatomy experts, thanks to a correlation scale. (3) Results: The overall average score for the 11 analyzed muscles or muscle groups was 3.36 out of 4, indicating a "strong" to "very strong" estimated correlation. There was a moderate agreement between Evaluator 1 and Evaluator 2 (ICC: 0.64; 95%CI: [0.244; 0.852]; p-value: 0.005). (4) Conclusions: The educational model with facial makeup provides an indirect but nonetheless precise and reliable representation of all facial muscles on the skin's surface. It is presented as a reliable and reproducible method, which exhibits great potential as a teaching tool.

Recent Developments in Engineering Non-Paralytic Botulinum Molecules for Therapeutic Applications

This review discusses the expanding application of botulinum neurotoxin in treating neurological conditions. The article specifically explores novel approaches to using non-paralytic botulinum molecules. These new molecules, such as BiTox or el-iBoNT, offer an alternative for patients who face limitations in using paralytic forms of botulinum neurotoxin due to concerns about muscle function loss. We highlight the research findings that confirm not only the effectiveness of these molecules but also their reduced paralytic effect. We also discuss a potential cause for the diminished paralytic action of these molecules, specifically changes in the spatial parameters of the new botulinum molecules. In summary, this article reviews the current research that enhances our understanding of the application of new botulinum neurotoxins in the context of common conditions and suggests new avenues for developing more efficient molecules.

Mapping the Vascular and Muscular Topography of the Glabellar Region: Implication for Improving Safety and Efficacy of the Glabellar Injections

BACKGROUND

Botulinum neurotoxin (BoNT) and filler injections into the highly vascularized glabellar region for aesthetical purposes are extremely common. Injections into the glabellar region without precise anatomical knowledge of its vascular and muscular topography may pose the risk of severe complications.

OBJECTIVES

We aimed to improve the safety and efficacy of the glabellar injections by mapping the regional muscles and vasculature in relation to the medial canthus and the defined reference lines.

METHODS

Meticulous dissection was performed to reveal glabellar region muscles and arteries under surgical microscope, in 16 hemifaces of whom arteries are injected with red-dyed latex. Location of the angular artery (AA) along with its branches was noted in relation to glabellar muscles.

RESULTS

The AA was always located superficial to the levator labii superioris alaeque nasi muscle (LLSAN) and then coursed toward the medial canthus to anastomose with the supratrochlear artery deep to the origin of the depressor supercilii (DS). The AA gave subcutaneously located central and paracentral branches coursing close to the mid-face line in 14 out of 16 hemifaces. Variable muscular connections were also present between the LLSAN, the DS and the procerus (P) muscles. No arteries were detected at the base of the medial eyebrow to which the DS, the P, and the frontalis (F) inserted.

CONCLUSIONS

This study provides a detailed map of muscular and vascular anatomy of the glabellar region to facilitate safe and efficient filler and BoNT injections without complications.

NO LEVEL ASSIGNED

This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Intramuscular injections of botulinum toxin for the treatment of upper back myofascial pain syndrome: A systematic review of randomized controlled trials

BACKGROUND AND OBJECTIVE

Myofascial pain syndrome (MPS) is a chronic musculoskeletal disorder characterized by the presence of trigger points. Among the treatment options, botulinum toxin injections have been investigated. The aim of this paper was to provide a synthesis of the evidence on intramuscular botulinum toxin injections for upper back MPS.

DATABASES AND DATA TREATMENT

A systematic review of the literature was performed on the PubMed, Scopus and Cochrane Library, using the following formula: ("botulinum") AND ("musculoskeletal") AND ("upper back pain") OR ("myofascial pain").

RESULTS

Ten studies involving 651 patients were included. Patients in the control groups received placebo (saline solution) injections, anaesthetic injections + dry needling or anaesthetic injections. The analysis of the trials revealed modest methodological quality: one "Good quality" study, one "Fair" and the other "Poor". No major complications or serious adverse events were reported. Results provided conflicting evidence and did not demonstrate the superiority of botulinum toxin over comparators. Most of the included trials were characterized by a small sample size, weak power analysis, different clinical scores used and non-comparable follow-up periods. Even if there is no conclusive evidence, the favourable safety profile and the positive results of some secondary endpoints suggest a potentially beneficial action in pain control and quality of life.

CONCLUSION

The currently available studies show conflicting results. Their overall low methodological quality does not allow for solid evidence of superiority over other comparison treatments. Further insights are needed to properly profile patients who could benefit more from this peculiar injective approach.

SIGNIFICANCE

The randomized controlled trials included in this review compared using botulinum toxin to treat upper back MPS with placebo or active treatments (e.g., dry needling or anaesthetics) showing mixed results overall. Despite the lack of clear evidence of superiority, our study suggests that the use of botulinum toxin should not be discouraged. Its safety profile and encouraging results in pain control, motor recovery and disability reduction make it an interesting treatment, particularly in the subset of patients with moderate to severe chronic pain and active trigger points. To support the safety and efficacy of botulinum toxin, further high-quality studies are needed.

Transient Worsening of Dysphagia and Dysarthria after Treatment with Botulinum Toxin in Patients with Acquired Brain Injury

Although botulinum toxin is widely considered an effective and safe treatment for a variety of neurological conditions (such as disabling spasticity), local or systemic adverse effects have often been reported. This study describes three cases of patients with severe acquired brain injury who were receiving speech therapy for recovering dysphagia and dysarthria but showed worsening of these symptoms after receiving BoNT treatment for motor spasticity. To increase clinicians' knowledge of these adverse effects, we present our cases and explore their significance to avoid major complications such as aspiration pneumonia.

Skin Toxicities Associated with Botulin Toxin Injection for Aesthetic Procedures: Data from the European Spontaneous Reporting System

Botulinum toxin is a protein deriving from the bacteria Clostridium botulinum and it is widely used for the treatment of a variety of muscle hyperactivity syndromes and for cosmetic indications. Having a long-lasting effect, Botulinum toxin type A (BTA) is one of the most botulin toxin products used. Even if BTA has shown benefits in reducing the vertical lines between the eyebrows, Adverse Drug Reactions (ADRs) have been experienced as well, of which the most common ones are headache and drooping eyelids. In addition, since other local and systemic risks have been identified, a non-interventional post-authorization safety study (PASS) has been started. The aim of the present study was to report cases of skin toxicity associated with this drug, considering Individual Case Safety Reports (ICSRs) existing on the Eudravigilance website. Among 1464 ICSRs sent to the EV database, 718 ICSRs, including 5154 PTs, reported BTA as a suspected drug associated with cutaneous toxicity. The majority of patients experiencing BTA-induced skin toxicity were female (92.1%) belonging mostly to the age group of 18-64 years. The most serious criteria, when reported, were "Other Medically Important Condition" and "Caused/prolonged hospitalization", although the outcome was mainly reported as "Unknown". The most reported PTs, related to skin disorders, were: "Erythema", "Rash", "Pruritus", "Urticaria", "Swelling face", "Brow ptosis", "Eyelid ptosis", "Injection site pain", and "Angioedema". Considering that in most ICSRs, ADRs related to skin disorders were symptoms of hypersensitivity reactions which in some conditions could be life-threatening, further studies are required to better define the safety profile of BTA used for aesthetic procedures.

Aromatherapy for the brain: Lavender's healing effect on epilepsy, depression, anxiety, migraine, and Alzheimer's disease: A review article

Neurological diseases affect the nervous system, including the brain, spinal cord, cranial nerves, nerve roots, autonomic nervous system, neuromuscular junctions, and muscles. Herbal medicine has long been used to cure these diseases. One of these plants is lavender, which is composed of various compounds, including terpenes, such as linalool, limonene, triterpenes, linalyl acetate, alcohols, ketones, polyphenols, coumarins, cineole, and flavonoids. In this review, the literature was searched using scientific search engines and databases (Google Scholar, Science Direct, Scopus, and PubMed) for papers published between 1982 and 2020 via keywords, including review, lavender, and neurological disorders. This plant exerts its healing effect on many diseases, such as anxiety and depression through an inhibitory effect on GABA. The anti-inflammatory effects of this plant have also been documented. It improves depression by regulating glutamate receptors and inhibiting calcium channels and serotonergic factors, such as SERT. Its antiepileptic mechanism is due to an increase in the inhibitory effect of GABA and potassium current and a decrease in sodium current. Therefore, many vegetable oils are also used in herbal medicine. In this review, the healing effect of lavender on several neurological disorders, including epilepsy, depression, anxiety, migraine, and Alzheimer's disease was investigated. All findings strongly support the traditional uses of lavender. More clinical studies are needed to investigate the effect of the plants' pharmacological active constituents on the treatment of life-threatening diseases in humans. The limitations of this study are the low quality and the limited number of clinical studies. Different administration methods of lavender are one of the limitations of this review.

Bruxism and Botulinum Injection: Challenges and Insights

Botulinum toxin (BTA) is a bacterial-derived extract that can inhibit muscle contraction, acting directly on the absorption of acetylcholine. Thanks to this property, botulinum has been used in aesthetic and general medicine for several years. Nowadays, the use of botulinum toxin is being deepened to address the problem of bruxism. In this scoping review, the results of the studies in the literature of the last 10 years were analyzed. Indeed, 12 reports (found on PubMed, Web of Science, and Scopus, entering the keywords "BRUXISM" and "BOTULINUM TOXIN") were deemed eligible for inclusion in this review. In the studies reviewed, BTA was injected into different muscle groups: masseters, masseter and temporalis or masseter, temporalis, and medial pterygoid. Botulinum toxin injection is a viable therapeutic solution, especially in patients with poor compliance or without improvement in conventional treatment.

Is there a role for botulinum toxin A in the emergency setting for delayed abdominal wall closure in the management of the open abdomen? A systematic review

INTRODUCTION

Emergency laparotomy for either trauma or non-trauma indications is common and management is varied. Use of the open abdomen technique allowing for planned re-look is an option; however, performing delayed definitive fascial closure (DFC) following this can be a challenge. The use of botulinum toxin-A (BTX) infiltration into the lateral abdominal wall has been well documented within the elective setting; its use within the emergency setting is undecided. This systematic review assesses the efficacy and safety of BTX injection into the lateral abdominal wall muscles in the emergency setting. The primary outcome is DFC rate.

METHODS

Systematic review was performed according to the PROSPERO registered protocol (CRD42020205130). Papers were dual screened for eligibility, and included if they met pre-stated criteria where the primary outcome was DFC. Articles reporting fewer than five cases were excluded. Bias was assessed using the Cochrane Risk of Bias and Joanna Brigg's appraisal tools.

FINDINGS

Fourteen studies were screened for eligibility, twelve full texts were reviewed and two studies were included. Both studies showed evidence of bias due to confounding factors and lack of reporting. Both studies suggested significantly higher rates of DFC than reported in the literature against standard technique (90.7% vs 66%); however, these data are difficult to interpret due to strict study inclusion criteria or lack of a control population.

CONCLUSION

The use of BTX is deemed safe and its effects in the emergency situation may have great potential. Unfortunately, to date, there is insufficient evidence to facilitate opinion.

Transformation of a Metal Chelate into a "Catch and Anchor" Inhibitor of Botulinum A Protease

Targeting the botulinum neurotoxin light chain (LC) metalloprotease using small-molecule metal chelate inhibitors is a promising approach to counter the effects of the lethal toxin. However, to overcome the pitfalls associated with simple reversible metal chelate inhibitors, it is crucial to investigate alternative scaffolds/strategies. In conjunction with Atomwise Inc., in silico and in vitro screenings were conducted, yielding a number of leads, including a novel 9-hydroxy-4H-pyrido [1,2-a]pyrimidin-4-one (PPO) scaffold. From this structure, an additional series of 43 derivatives were synthesized and tested, resulting in a lead candidate with a K_i of 150 nM in a BoNT/A LC enzyme assay and 17 µM in a motor neuron cell-based assay. These data combined with structure-activity relationship (SAR) analysis and docking led to a bifunctional design strategy, which we termed "catch and anchor" for the covalent inhibition of BoNT/A LC. Kinetic evaluation was conducted on structures prepared from this catch and anchor campaign, providing k_inact/K_i values, and rationale for inhibition seen. Covalent modification was validated through additional assays, including an FRET endpoint assay, mass spectrometry, and exhaustive enzyme dialysis. The data presented support the PPO scaffold as a novel candidate for targeted covalent inhibition of BoNT/A LC.

The Place of Botulinum Toxin in Spastic Hemiplegic Shoulder Pain after Stroke: A Scoping Review

Stroke is a common pathology worldwide, with an age-standardized global rate of new strokes of 150.5 per 100,000 population in 2017. Stroke causes upper motor neuron impairment leading to a spectrum of muscle weakness around the shoulder joint, changes in muscle tone, and subsequent soft tissue changes. Hemiplegic shoulder pain (HSP) is the most common pain condition in stroke patients and one of the four most common medical complications after stroke. The importance of the appropriate positioning and handling of the hemiplegic shoulder for prevention of HSP is therefore of high clinical relevance. Nevertheless, HSP remains a frequent and disabling problem after stroke, with a 1-year prevalence rate up to 39%. Furthermore, the severity of the motor impairment is one of the most important identified risk factors for HSP in literature. Spasticity is one of these motor impairments that is likely to be modifiable. After ruling out or treating other shoulder pathologies, spasticity must be assessed and treated because it could lead to a cascade of unwanted complications, including spastic HSP. In clinical practice, Botulinum toxin A (BTA) is regarded as the first-choice treatment of focal spasticity in the upper limb, as it gives the opportunity to target specifically selected muscles. It thereby provides the possibility of a unique patient tailored focal and reversible treatment for post stroke spasticity. This scoping review aims to summarize the current evidence of BTA treatment for spastic HSP. First, the clinical manifestation and outcome measures of spastic HSP will be addressed, and second the current evidence of BTA treatment of spastic HSP will be reviewed. We also go in-depth into the elements of BTA application that may optimize the therapeutic effect of BTA. Finally, future considerations for the use of BTA for spastic HSP in clinical practice and research settings will be discussed.

Assessing the Reporting of Harms in Systematic Reviews Focused on the Therapeutic and Cosmetic Uses of Botulinum Toxin

BACKGROUND AND OBJECTIVE

The expanding use of botulinum toxin (BoNT) in medical practice demonstrates the need to highlight whether there is adequate information regarding its safety profile. The aim of our study was to identify completeness of harms reporting for BoNT treatment within systematic reviews (SRs), assess quality of SRs using the AMSTAR-2 tool, and determine the degree of overlap among primary studies within each SR.

METHODS

On May 31, 2022, we searched Embase, Epistemonikos, MEDLINE, and the Cochrane Database of Systematic Reviews for SRs on BoNT therapy. Screening and data extraction were performed in a masked, duplicate fashion. AMSTAR-2 was used to evaluate the methodological quality of included SRs. Corrected covered area (CCA) was calculated for SR dyads.

RESULTS

Of the 90 included SRs, we found that 70 completed less than 50% of harms items. The most reported items were BoNT as a favorable intervention (73/90, 81.1%) and harms as a primary outcome (72/90, 80.0%). The least reported items were grades and severity scales used to classify harms (8/90, 8.9%) and number of treatment discontinuations in each arm (10/90, 11.1%). Eighty-three SRs were rated "critically low" (83/90, 92.2%), while 5 SRs were rated "high" (5/90, 5.6%) via AMSTAR-2 tool. Significant associations were found between completion of harms reporting and: (1) a "critically low" appraisal on AMSTAR-2 tool (p = 0.0060) and (2) whether harms was reported as a primary outcome (p = 0.0001). The total CCA overlap was determined to be 0.8%.

CONCLUSION

Our results demonstrate that harms are underreported within BoNT SRs. Because healthcare professionals often refer to SRs to guide clinical decision making, it is important to continue to explore shortcomings among BoNT literature in future studies.

Anatomical Proposal for Botulinum Neurotoxin Injection Targeting the Platysma Muscle for Treating Platysmal Band and Jawline Lifting: A Review

The platysma muscle is a thin superficial muscle that covers the entire neck and lower part of the face. The platysma muscle is the primary target muscle for botulinum neurotoxin injection therapy aimed at treating platysmal band and lower facial lifting. In the procedure of botulinum neurotoxin injection therapy, a lack of knowledge of the anatomy of the platysma muscle and the properties of botulinum neurotoxin can lead to side effects such as dysphagia, dysphonia, and weakness of the neck muscles. Anatomically safe injection sites have been proposed for the platysma muscle, and the appropriate injection technique has been reviewed. We proposed optimal injection sites based on the external anatomical features of the mandible. The aim of these proposal was to standardize the procedure for the effective use of botulinum neurotoxin injections by minimizing the dose unit and injection points and thereby preventing adverse events.

Lambert-Eaton Myasthenic Syndrome and Botulism

PURPOSE OF REVIEW

This article reviews the pathophysiology, epidemiology, clinical features, diagnosis, and treatment of Lambert-Eaton myasthenic syndrome (LEMS) and botulism, presynaptic disorders of neuromuscular transmission in which rapid diagnosis improves long-term outcomes.

RECENT FINDINGS

Therapy for LEMS has seen significant advances in recent years due to the approval of amifampridine-based compounds. LEMS is likely still underdiagnosed, particularly when no underlying malignancy is identified. Clinicians must have a strong suspicion for LEMS in any patient presenting with proximal weakness and autonomic dysfunction. Botulism is another rare disorder of presynaptic neuromuscular transmission that is most commonly associated with improper storage or preservation of food products. Over the past 2 decades, wound botulism has been increasingly reported among users of black tar heroin. A high degree of clinical suspicion and electrodiagnostic studies can be beneficial in distinguishing botulism from other acute neurologic disorders, and early involvement of state and federal health authorities may assist in confirming the diagnosis and obtaining treatment. When botulism is suspected, electrodiagnostic studies can provide clinical evidence of disordered neuromuscular transmission in advance of serologic confirmation, and providers should not wait for confirmation of the diagnosis to initiate treatment.

SUMMARY

A targeted clinical history and a thorough neurologic examination with support from serologic and electrodiagnostic studies are key to early diagnosis of LEMS and botulism. Early diagnosis of both conditions creates opportunities for therapy and improves outcomes.

Reasons and Determinants of BoNT-A Treatment Discontinuation in Patients Living with Spasticity: A 10-Year Retrospective Analysis

BACKGROUND

The present study aimed to evaluate the reasons and determinants of BoNT-A discontinuation in patients with stroke, multiple sclerosis, spinal cord injury, and traumatic brain injury.

METHODS

It is a retrospective study of 56 discontinuer patients treated with botulinum toxin between January 2011 and December 2021. Discontinuation rates and their predictors were estimated using Kaplan-Meier, Log rank test, and Cox's regression method of analyses.

RESULTS

The mean age was 56.54 years, 53.57% were affected by post-stroke spasticity, 17.86% by spinal cord injury, 12.5% and 16.07% by traumatic brain injury and multiple sclerosis, respectively. The median discontinuation time was 5 months. The main reason for discontinuation were logistic problems (37%) and orthopedic surgeries or intrathecal baclofen (27%). Discontinuers were more likely to have severe spasticity (R = 1.785), have no pain (HR = 1.320), no access to rehabilitation services (HR = 1.402), and have cognitive impairment (HR = 1.403).

CONCLUSIONS

The main reasons for discontinuation are related to logistic issues (due to distance or the absence of an adequate caregiver) and surgical interventions for spasticity, including intrathecal baclofen. It is crucial to identify possible predictors of discontinuation to improve the effectiveness of a multidisciplinary management. The study confirms the crucial role of rehabilitation and caregivers in achieving better long-term outcomes.

The Lack of Systemic and Subclinical Side Effects of Botulinum Neurotoxin Type-A in Patients Affected by Post-Stroke Spasticity: A Longitudinal Cohort Study

Botulinum Neurotoxin type-A (BoNT-A) is the treatment of choice for focal post-stroke spasticity (PSS). Due to its mechanism of action and the administration method, some authors raised concern about its possible systemic diffusion leading to contralateral muscle weakness and autonomic nervous system (ANS) alterations. Stroke itself is a cause of motor disability and ANS impairment; therefore, it is mandatory to prevent any source of additional loss of strength and adjunctive ANS disturbance. We enrolled 15 hemiparetic stroke survivors affected by PSS already addressed to BoNT-A treatment. Contralateral handgrip strength and ANS parameters, such as heart rate variability, impedance cardiography values, and respiratory sinus arrythmia, were measured 24 h before (T0) and 10 days after (T1) the ultrasound (US)-guided BoNT-A injection. At T1, neither strength loss nor modification of the basal ANS patterns were found. These findings support recent literature about the safety profile of BoNT-A, endorsing the importance of the US guide for a precise targeting and the sparing of “critical” structures as vessels and nerves.

The Necessity of a Locally Active Antidote in the Clinical Practice of Botulinum Neurotoxin Therapy: Short Communication

Recently, it was demonstrated that copper complexes and 3,4-diaminopyridine can effectively reduce the activity of the botulinum neurotoxin light chain. The aim of the present study was to indicate that treatment with an antidote may have a major influence, not only on the extremely rare disease of botulism, but also on the much more frequently occurring side effects experienced during BoNT therapy. This was a retrospective chart review of patients who were regularly treated with BoNT for various indications. The percentage of patients with clinical signs of overdosing was determined. In patients with facial dystonia, double vision and ptosis occurred as side effects. In patients with cervical dystonia, neck weakness and dysphagia were observed as the most frequent side effects. In oromandibular and oropharyngeal dystonia, abnormal tongue movements and dysphagia occurred frequently. In writer’s cramp and mild post-stroke hand spasticity, severe paresis of the injected and non-injected finger muscles was observed. Additionally, in the BoNT treatment of pain syndromes (such as tension headaches or migraines), neck weakness may occur. Across all indications for clinical BoNT applications, clinical signs of BoNT overdosing may occur in up to 5% of the BoNT-treated patients. Therefore, the development of an antidote for BoNT overdoses would be very much appreciated and would have a major influence on the management of BoNT therapy.

Therapeutic Efficacy of Botulinum Toxin in Trigeminal Neuralgia

Trigeminal neuralgia (TN) is a unilateral, paroxysmal, sharp, shooting, or jabbing pain that occurs in the trigeminal nerve divisions, including the ophthalmic (V1), maxillary (V2), and mandibular (V3) nerves. Typically, an episode is triggered by anything touching the face or teeth. TN is a clinical diagnosis with no specific diagnostic test; it is determined by the patient's medical history and pain description. Imaging is necessary to exclude secondary causes. The precise reason for TN is uncertain, but it is commonly believed to result from vascular compression of the trigeminal nerve root, typically near its origin in the pons. There are numerous surgical and medical treatment options available. The most frequently applied medical treatment therapies are carbamazepine and oxcarbazepine. Surgical alternatives are reserved for patients who do not respond to medical treatment. Botulinum toxin A (BTX-A) has emerged as a novel and promising alternative to surgery for individuals whose pain is unresponsive to medication. Multiple studies have established the safety and usefulness of BTX-A in treating TN, with the most significant benefits occurring between six weeks and three months after the surgery. This article reviews various studies published in the last 10 years regarding the therapeutic use of BTX-A in TN. These studies include various observational, clinical, pilot, and animal studies.

Treatment of sialorrhea with botulinum toxin injections in pediatric patients less than three years of age

OBJECTIVE

To determine the patient demographics and the efficacy and safety profile of botulinum toxin (BTX) injections for sialorrhea control in patients under the age of three.

METHODS

This is a retrospective chart review study. Patients under three years of age who received BTX injections for sialorrhea management from 2010 to 2021 were assessed. Patient demographics, comorbidities, medical and surgical histories, indications, BTX injection details, and post injection complications were documented.

RESULTS

Forty-nine patients met inclusion criteria. The most common patient under three years of age with sialorrhea to receive BTX injections were white (51.0%) male (51.0%) with congenital (73.5%) and/or neurologic (53.1%) comorbidities. Thirty-six (73.5%) patients were from medically underserved areas/populations. Our patients on average received 1.7 injections, with 44.9% requiring multiple BTX injections. Bilateral parotid and bilateral submandibular glands (four-gland) BTX injections were associated with significant decrease in admissions for pneumonia and cessation of anticholinergics usage (both P < 0.05). Post BTX injections, 15 (30.6%) patients required additional surgeries for sialorrhea control. No adverse outcomes due to BTX injections were reported.

CONCLUSIONS

Pediatric sialorrhea was commonly associated with congenital and/or neurologic comorbidities and disproportionately impacted medically underserved black patients. BTX injections offered multifaceted benefits for controlling sialorrhea in patients under the age of three. Four-gland BTX injections led to reduction of unnecessary hospitalization, usage of anticholinergics, and additional surgeries for sialorrhea management.

Efficacy and safety of botulinum A toxin for the treatment of chronic peripheral neuropathic pain: A systematic review of randomized controlled trials and meta-analysis

BACKGROUND AND OBJECTIVE

Botulinum toxin type A (BTX-A) is a recently developed treatment for the management of peripheral neuropathic pain. The objective of this study was to provide a synthesis of the evidence concerning the efficacy and safety of subcutaneous botulinum toxin type A injections.

DATABASES AND DATA TREATMENT

We searched the MEDLINE, EMBASE, LILACS, Cochrane, and Clinical Trial Register databases for randomized controlled trials comparing subcutaneous BTX-A to placebo injections for treating chronic peripheral neuropathic pain. The primary endpoint was the assessment of pain 1 month after the injection. The secondary outcomes were the assessment of pain at 3 months, neuropathic pain intensity and quality of life at 1 and 3 months, and adverse effects. A random-effect meta-analysis was performed on the combined data. Evidence quality was rated by the Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) method.

RESULTS

Ten randomized controlled trials including 505 patients were included in this review (registration number CRD42021239108). At 1 and 3 months after injection, the BTX-A groups had a lower mean difference (MD) in pain score (MD -1.87 (confidence intervals [CIs] -2.91; -0.83) and -1.38 (CI -1.95; -0.81), respectively). Subgroup analysis showed greater efficacy for diabetic polyneuropathy (MD -2.48, [-3.22; -1.74]). We found no impact of BTX-A on quality of life and no difference in adverse effect between BTX-A and placebo. The evidence was considered of moderate quality.

CONCLUSION

The pooled data suggest that subcutaneous BTX-A injections have a clinically significant effect, decreasing pain for three months after the injection, but no benefit in terms of quality of life has yet been demonstrated.

SIGNIFICANCE

We found that botulinum toxin is efficient and safe for the treatment of neuropathic pain, especially for diabetic polyneuropathy. Botulinum toxin type A, used for years in neurology, rehabilitation and physical medicine, has proved innocuous and effective, and should be considered as a serious alternative for pain treatment.

First-in-Human Clinical Trial to Assess the Safety, Tolerability and Pharmacokinetics of Single Doses of NTM-1633, a Novel Mixture of Monoclonal Antibodies against Botulinum Toxin E

Botulism is a rare, life-threatening paralytic disease caused by botulinum neurotoxin (BoNT). Available treatments including an equine antitoxin and human immune globulin are given postexposure and challenging to produce and administer. NTM-1633 is an equimolar mixture of 3 human IgG monoclonal antibodies, E1, E2, and E3, targeting BoNT serotype E (BoNT/E). This first-in-human study assessed the safety, tolerability, pharmacokinetics (PK), and immunogenicity of NTM-1633. This double-blind, single-center, placebo-controlled dose escalation study randomized 3 cohorts of healthy volunteers to receive a single intravenous dose of NTM-1633 (0.033, 0.165, or 0.330 mg/kg) or saline placebo. Safety monitoring included physical examinations, clinical laboratory studies, and vital signs. Blood sampling was performed at prespecified time points for PK and immunogenicity analyses. Twenty-four subjects received study product (18 NTM-1633; 6 placebo), and no deaths were reported. An unrelated serious adverse event was reported in a placebo subject. Adverse events in the NTM-1633 groups were generally mild and similar in frequency and severity to the placebo group, and no safety signal was identified. NTM-1633 has a favorable PK profile with a half-life >10 days for the 0.330 mg/kg dose and an approximately linear relationship with respect to maximum concentration and area under the concentration-time curve (AUC0→t). NTM-1633 also demonstrated low immunogenicity. NTM-1633 is well tolerated at the administered doses. The favorable safety, PK, and immunogenicity profile supports further development as a treatment for BoNT/E intoxication and postexposure prophylaxis.

Complications of Cosmetic Botulinum Toxin A Injections to the Upper Face: A Systematic Review and Meta-Analysis

Background

Botulinum toxin A (BoNT-A) injections are a popular non-surgical procedure for facial rejuvenation. Its increase in popularity and utilization is met with limited regulations, potentially posing a significant risk to patient safety and public health.

Objectives

The authors sought to assess the safety profile of cosmetic glabellar and forehead BoNT-A injections and evaluate BoNT-A type on complication rate.

Methods

A systematic search of MEDLINE and EMBASE was performed for studies reporting complications after cosmetic BoNT-A in the glabellar or in the forehead region in the glabellar or in the forehead region. A random effects meta-analysis was carried out to assess complication rate. Where there were sufficient randomized-controlled trials, a network meta-analysis was performed.

Results

Of 556 identified articles, 24 were included in the final quantitative analysis, with 4268 BoNT-A injection sessions and 1234 placebos. Frequently observed treatment-related complications in the BoNT-A intervention group included headache, local skin reactions, and facial neuromuscular symptoms. The overall BoNT-A complication rate was 16%. The odds ratio of developing complications from abobotulinum toxin injections compared with placebo was 1.62 (1.15, 2.27; P > 0.05) and that from onabotulinum toxin injections compared with placebo was 1.34 (0.52, 3.48; P > 0.05). In 30% of the studies, the injectors were doctors, whereas the training status of the practitioner was not reported in the remaining 70%.

Conclusions

Cosmetic BoNT-A injections in the glabellar and forehead region appear to be safe, and most complications are mild and transient. Nevertheless, the literature demonstrates heterogeneous reporting of complications and a lack of consistency of the definition of treatment-related complications.

Level of Evidence: 2

Toxicology and pharmacology of botulinum and tetanus neurotoxins: an update

Tetanus and botulinum neurotoxins cause the neuroparalytic syndromes of tetanus and botulism, respectively, by delivering inside different types of neurons, metalloproteases specifically cleaving the SNARE proteins that are essential for the release of neurotransmitters. Research on their mechanism of action is intensively carried out in order to devise improved therapies based on antibodies and chemical drugs. Recently, major results have been obtained with human monoclonal antibodies and with single chain antibodies that have allowed one to neutralize the metalloprotease activity of botulinum neurotoxin type A1 inside neurons. In addition, a method has been devised to induce a rapid molecular evolution of the metalloprotease domain of botulinum neurotoxin followed by selection driven to re-target the metalloprotease activity versus novel targets with respect to the SNARE proteins. At the same time, an intense and wide spectrum clinical research on novel therapeutics based on botulinum neurotoxins is carried out, which are also reviewed here.

Long-term Effects of Repeated Botulinum Toxin Injection in Cosmetic Therapeutics

BACKGROUND

Botulinum toxin (BT), a potent neurotoxin, has been used in clinical medicine since the 1970s for cosmetic and therapeutic purposes. Studies have consistently shown positive outcomes with a very limited adverse effect profile and a conventional understanding that results dissipate after 3 to 5 months. However, more recent evidence suggests that changes in muscle composition, function, and appearance persist for much longer, even years. To examine the potential implications of these findings on cosmetic use of BT injections in reduction of skin lines and wrinkles, we first needed to further our understanding of the current literature on long-term outcomes after repeated BT injections.

METHODS

A comprehensive review of the literature on long-term outcomes after repeated BT injections for cosmetic indications was performed. We evaluated the study designs, and results were compared.

RESULTS

A total of 22 publications met our inclusion criteria, of which 14 were clinical trials. Few studies extended outcome measurement past 6 months postinjection, and many were funded or supported by industry. However, the studies that extended follow-up saw persistent changes after BT injection, in some cases as far as 4 years postinjection.

CONCLUSION

The current body of knowledge on the long-term results after repeated cosmetic BT injections is very limited, and the available literature provides insufficient evidence on how prolonged effects could alter clinical use of BT. Further clinical studies with extended follow-up periods with inclusion of both subjective and objective measured outcomes of appearance and muscle function are required to better understand the long-term impacts of repeated BT injections.

High Precision Use of Botulinum Toxin Type A (BONT-A) in Aesthetics Based on Muscle Atrophy, Is Muscular Architecture Reprogramming a Possibility? A Systematic Review of Literature on Muscle Atrophy after BoNT-A Injections

Improvements in Botulinum toxin type-A (BoNT-A) aesthetic treatments have been jeopardized by the simplistic statement: “BoNT-A treats wrinkles”. BoNT-A monotherapy relating to wrinkles is, at least, questionable. The BoNT-A mechanism of action is presynaptic cholinergic nerve terminals blockage, causing paralysis and subsequent muscle atrophy. Understanding the real BoNT-A mechanism of action clarifies misconceptions that impact the way scientific productions on the subject are designed, the way aesthetics treatments are proposed, and how limited the results are when the focus is only on wrinkle softening. We designed a systematic review on BoNT-A and muscle atrophy that could enlighten new approaches for aesthetics purposes. A systematic review, targeting articles investigating BoNT-A injection and its correlation to muscle atrophy in animals or humans, filtered 30 publications released before 15 May 2020 in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Histologic analysis and histochemistry showed muscle atrophy with fibrosis, necrosis, and an increase in the number of perimysial fat cells in animal and human models; this was also confirmed by imaging studies. A significant muscle balance reduction of 18% to 60% after single or seriated BoNT-A injections were observed in 9 out of 10 animal studies. Genetic alterations related to muscle atrophy were analyzed by five studies and showed how much impact a single BoNT-A injection can cause on a molecular basis. Seriated or single BoNT-A muscle injections can cause real muscle atrophy on a short or long-term basis, in animal models and in humans. Theoretically, muscular architecture reprogramming is a possible new approach in aesthetics.

Physicians’ Practice of the Non-Cosmetic Uses of Botulinum Toxin: A Cross-Sectional Study in Saudi Arabia

Background

Although botulinum toxin (BTX) has mainly been used cosmetically and therapeutically, its field of application is expanding. So far, BTX has shown promising outcomes in the management of a wide variety of medical conditions that are difficult to treat.

Objectives

We assessed physicians’ knowledge and experience regarding the non-cosmetic use of BTX in different clinical settings.

Methods

This is a cross-sectional survey that was conducted in Riyadh, Saudi Arabia, and included physicians from different specialties, with different levels of training, and from different working hospitals. Data were collected by using a self-administered survey to assess physicians’ knowledge, experience, current practice, and specific training in relation to Botox administration for non-cosmetic use.

Results

Most participants were residents (76.19%) and specialized in internal medicine (27.62%). The majority worked in governmental hospitals (76.19%). About 73% of our sample were aware of the non-cosmetic indications of BTX, but only 44% and 55% were aware of its contraindications and adverse effects, respectively. Less than one-third (31%) of respondents administered BTX injections in their clinical practice, and about 66% of respondents had two to five years of experience giving BTX injections. The most commonly treated conditions were spastic disorders, dystonia, and then migraine. Only 4.7% and 3.6% used validated scales or instruments for planning treatment with BTX, respectively, while about 36% opted for clinical evaluation only. More experience and training in giving BTX injections significantly predicted increased awareness of adverse effects and contraindications of non-cosmetic uses. 

Conclusions

The majority of specialty groups in our sample were aware of the non-cosmetic applications of botulinum toxin but did not use them to the same extent in their practice. Additionally, only a minority wished for further education on injection practices. The finding of insufficient knowledge about contraindications and the adverse effects of injections in a large number of participants, however, highlights the need for increased education, especially given the wide range of non-cosmetic applications and benefits that BTX can have for a variety of diseases.

Safety of Aesthetic Medicine Procedures in Patients with Autoimmune Thyroid Disease: A Literature Review

Autoimmune thyroid diseases are the most common organ-specific autoimmune diseases, affecting 2–5% of the world’s population. Due to the autoimmune background of thyroid diseases, we analyzed a wide range of cosmetic procedures, from minimally invasive cosmetic injections (mesotherapy) to highly invasive procedures, such as lifting threads. Out of the seven categories of treatments in aesthetic medicine analyzed by us—hyaluronic acid, botulinum toxin, autologous platelet-rich plasma, autologous fat grafting, lifting threads, IPL and laser treatment and mesotherapy—only two, mesotherapy and lifting threads, are not recommended. This is due to the lack of safety studies and the potential possibility of a higher frequency of side effects in patients with autoimmune thyroid diseases.

Sub-acute hypersensitive reaction to botulinum toxin type A following Covid-19 vaccination: Case report and literature review

RATIONALE

Botulinum toxin type A (BTA) is one of the most widely used injectable agents in cosmetic surgery. Corona virus disease 2019 (Covid-19) infection and vaccination, which can induce specific and nonspecific activation of the immune system, has been reported to induce delayed inflammatory reactions to previously injected hyaluronic acid fillers. However, there are no reports about the interaction between BTA and Covid-19. We aimed to report 2 sub-acute cases of allergic reactions to BTA in facial cosmesis following the Covid-19 vaccination.

PATIENT CONCERN

A 35-year-old and a 34-year-old female who has several previous BTA injections without any adverse effects experienced facial swelling, flu-like symptoms after BTA treatment following the Covid-19 vaccination.

DIAGNOSE

According to the typical clinical manifestation, a hypersensitive reaction to BTA was considered.

INTERVENTION

Corticosteroids and antihistamine were administered empirically.

OUTCOMES

The flu-like symptoms recovered over the next day, but the facial swelling gradually faded within 1 to 2 weeks.

LESSONS

A literature review was also conducted to summarize the hypersensitive actions to cosmesis related to Covid-19. We recommend BTA injection be administered at least 2 to 3 months after Covid-19 vaccination.

Current Use of Cosmetic Toxins to Improve Facial Aesthetics

LEARNING OBJECTIVES

After studying this article, the participant should be able to: 1. Compare and contrast the various types of botulinum toxin on the market. 2. Appropriately select patients for treatment with cosmetic botulinum toxin. 3. Understand the common injection patterns for treating various regions of the face with cosmetic botulinum toxin. 4. List the complications associated with treating various regions of the face with cosmetic botulinum toxin.

SUMMARY

Nonsurgical rejuvenation of the face with botulinum toxin is one of the most commonly performed procedures in the United States. This article reviews the current evidence in treating different regions of the face: upper face, lower face, masseter, and platysma. Dosing and complications associated with different facial regions are reviewed.

The Effect of Turbinate Injection of Botulinum Toxin A on the Symptoms of Idiopathic Rhinitis

Introduction  Idiopathic rhinitis is a nonallergic and noninfectious rhinitis characterized mainly by nasal obstruction and rhinorrhea, resulting from an autonomic imbalance. Botulinum toxin type A (BTX-A) demonstrated its action in reducing rhinorrhea and nasal obstruction when injected into the nasal turbinates or septum.

Objective  To analyze the effects of intranasal BTX-A injection to control the symptoms of idiopathic rhinitis and its possible adverse effects.

Method  Patients with idiopathic rhinitis were divided into two groups. Group A had 15 participants (8 female and 6 male), of ages from 47 to 84 years (mean 66.57 years), and these received 60 U of Dysport (Ipsen Ltd, Maidenhead, Berkshire, UK) in each inferior nasal turbinate; group B had 12 participants (1 male and 11 female), of ages from 50 to 76 years (mean 60 years), and they received 1 ml of 0.9% saline. The individuals were reevaluated in the 1 ^st , 2 ^nd , 4 ^th , 8 ^th , and 12 ^th weeks after injection by a questionnaire, accompanied by nasal inspiratory peak flow and acoustic rhinometry.

Results  Group A showed significant improvement, mainly regarding the symptoms of sneezing/itching and nasal obstruction, over time and when compared to group B. Acoustic rhinometry confirmed the improvement in nasal obstruction. There was no relationship between the nasal peak flow data and the nasal obstruction score. No major adverse effects have been reported.

Conclusion  The injection of botulinum toxin in the inferior nasal turbinates of patients with idiopathic rhinitis reduces the symptoms of sneezing, itching, nasal obstruction, and runny nose without significant adverse effects, suggesting that it is an option in the treatment of these patients.

Use of Crystallography and Molecular Modeling for the Inhibition of the Botulinum Neurotoxin A Protease

Botulinum neurotoxins (BoNTs) are extremely toxic and have been deemed a Tier 1 potential bioterrorism agent. The most potent and persistent of the BoNTs is the "A" serotype, with strategies to counter its etiology focused on designing small-molecule inhibitors of its light chain (LC), a zinc-dependent metalloprotease. The successful structure-based drug design of inhibitors has been confounded as the LC is highly flexible with significant morphological changes occurring upon inhibitor binding. To achieve greater success, previous and new cocrystal structures were evaluated from the standpoint of inhibitor enantioselectivity and their effect on active-site morphology. Based upon these structural insights, we designed inhibitors that were predicted to take advantage of π-π stacking interactions present in a cryptic hydrophobic subpocket. Structure-activity relationships were defined, and X-ray crystal structures and docking models were examined to rationalize the observed potency differences between inhibitors.

Irreversible inhibition of BoNT/A protease: proximity-driven reactivity contingent upon a bifunctional approach

Botulinum neurotoxin A (BoNT/A) is categorized as a Tier 1 bioterrorism agent and persists within muscle neurons for months, causing paralysis. A readily available treatment that abrogates BoNT/A's toxicity and longevity is a necessity in the event of a widespread BoNT/A attack and for clinical treatment of botulism, yet remains an unmet need. Herein, we describe a comprehensive warhead screening campaign of bifunctional hydroxamate-based inhibitors for the irreversible inhibition of the BoNT/A light chain (LC). Using the 2,4-dichlorocinnamic hydroxamic acid (DCHA) metal-binding pharmacophore modified with a pendent warhead, a total of 37 compounds, possessing 13 distinct warhead types, were synthesized and evaluated for time-dependent inhibition against the BoNT/A LC. Iodoacetamides, maleimides, and an epoxide were found to exhibit time-dependent inhibition and their k GSH measured as a description of reactivity. The epoxide exhibited superior time-dependent inhibition over the iodoacetamides, despite reacting with glutathione (GSH) 51-fold slower. The proximity-driven covalent bond achieved with the epoxide inhibitor was contingent upon the vital hydroxamate-Zn2+ anchor in placing the warhead in an optimal position for reaction with Cys165. Monofunctional control compounds exemplified the necessity of the bifunctional approach, and Cys165 modification was confirmed through high-resolution mass spectrometry (HRMS) and ablation of time-dependent inhibitory activity against a C165A variant. Compounds were also evaluated against BoNT/A-intoxicated motor neuron cells, and their cell toxicity, serum stability, and selectivity against matrix metalloproteinases (MMPs) were characterized. The bifunctional approach allows the use of less intrinsically reactive electrophiles to intercept Cys165, thus expanding the toolbox of potential warheads for selective irreversible BoNT/A LC inhibition. We envision that this dual-targeted strategy is amenable to other metalloproteases that also possess non-catalytic cysteines proximal to the active-site metal center.

Safety, Tolerability, and Pharmacokinetics of NTM-1632, a Novel Mixture of Three Monoclonal Antibodies against Botulinum Toxin B

Botulism is a rare, life-threatening paralytic disease caused by Clostridium botulinum neurotoxin (BoNT). Available treatments, including an equine antitoxin and human immune globulin, are given postexposure and challenging to produce and administer. NTM-1632 is an equimolar mixture of 3 human IgG monoclonal antibodies, B1, B2, and B3, targeting BoNT serotype B (BoNT/B). This first-in-human study assessed the safety, tolerability, pharmacokinetics (PK), and immunogenicity of NTM-1632. This double-blind, single-center, placebo-controlled dose escalation study randomized 3 cohorts of healthy volunteers to receive a single intravenous dose of NTM-1632 (0.033, 0.165, or 0.330 mg/kg) or saline placebo. Safety monitoring included physical examinations, clinical laboratory studies, and vital signs. Blood sampling was performed at prespecified time points for PK and immunogenicity analyses. Twenty-four subjects received study product (18 NTM-1632; 6 placebo), and no deaths or serious adverse events were reported. Adverse events in the NTM-1632 groups were generally mild and similar in frequency and severity to the placebo group, and no safety signal was identified. NTM-1632 has a favorable PK profile with a half-life of >20 days for the 0.330-mg/kg dose and an approximately linear relationship with respect to maximum concentration and area under the concentration-time curve (AUC_0→t). NTM-1632 demonstrated low immunogenicity with only a few treatment-emergent antidrug antibody responses in the low and middle dosing groups and none at the highest dose. NTM-1632 is well tolerated at the administered doses. The favorable safety, PK, and immunogenicity profile of NTM-1632 supports further clinical development as a treatment for BoNT/B intoxication and postexposure prophylaxis. (This study has been registered at ClinicalTrials.gov under identifier NCT02779140.).

Complications of facial cosmetic botulinum toxin A injection: analysis of the UK Medicines & Healthcare Products Regulatory Agency registry and literature review

BACKGROUND

Botulinum toxin A (BoNT-A) injection is one of the most frequently undertaken procedures in aesthetic medicine. The Medicines & Healthcare products Regulatory Agency (MHRA) is the government body in the United Kingdom (UK) mandated to ensure that the provision and administration of medicines is safe. We analyzed adverse events of facial cosmetic BoNT-A injections reported to the MHRA and assessed whether the incidence of reported adverse events in this government registry is comparable to published retrospective and prospective studies.

METHODS

A freedom of information (FOI) request was submitted to the MHRA to obtain recorded complications of BoNT- A. Complications reported to the MHRA between 1991 and 2020 were analyzed. Only cases with BoNT-A where the indication was specified as for facial cosmetics were included in the analysis. Additionally, the literature was reviewed on adverse events of facial cosmetic BoNT- A injections, and a statistical meta-analysis of complication rates was carried out.

RESULTS

A total of 188 adverse events of aesthetic BoNT-A injections were reported to the MHRA. The literature search resulted in 30 studies and a total of 17,352 injection sessions, where the complication rate was 16% (95% CI = 8% to 25%). Frequent adverse events included localized skin reactions such as bruising with an incidence of 5% (95% CI = 3% to 7%), headache in 3% (95% CI = from 1% to 5% ), and facial paresis in 2% (95% CI = 1% to 3%) of injection sessions.

CONCLUSIONS

This is the first paper to obtain and evaluate data on adverse events of BoNT-A from the MHRA. An estimate of the likely complication rate of aesthetic BoNT-A in the UK, according to the MHRA database, is significantly lower than the rate recorded from our meta-analysis of the international literature. This suggests that the MHRA may be underestimating the adverse events of aesthetic BoNT-A treatment, which would have implications for patient safety and informed consent. Therefore, legislative changes may be required to ensure more robust reporting of aesthetic BoNT-A in the UK.

Adverse Events Associated With Botox as Reported in a Food and Drug Administration Database

BACKGROUND

Botulinum toxin treatment is the most frequently performed noninvasive cosmetic procedure performed in the USA. Because of its widespread use, an analysis of the adverse event (AE) profile of Botox injections is needed.

METHODS

The FDA Adverse Event Report System was queried using an online web-based tool to determine the top 15 adverse events reported for four Botox brand names: Botox/Botox Cosmetic, Dysport, and Xeomin. The proportional reporting ratios (PRR) and relative odds ratios (ROR) were determined. A literature review was performed for eight AEs of clinical significance: eyelid/eyebrow ptosis, asthenia, muscular weakness, facial paresis, dysphagia, botulism, and death.

RESULTS

Botox/Botox Cosmetic had 38367 AEs. Dysport had 3582 AEs. Xeomin had 1405 AEs. All drugs with reported cases of eyelid and eyebrow ptosis had significant PRR and ROR values. The PRR and ROR values for asthenia were not significant in any of the drugs and only reached significance for Dysport for muscular weakness and dysphagia. Both Botox/Botox Cosmetic and Dysport had elevated PRRs and RORs for facial paresis and botulism. While all drugs had at least one reported case of death related to Botox injection use, none of the PRR or ROR values were significant.

CONCLUSION

Known AEs for Botox injection use include eyelid/brow ptosis and muscular weakness. Feared but rare complications of Botox injection use include dysphagia, botulism, and possibly death, owing to systemic spread of the toxin. This is the first study to analyze the AE data reported to the FDA on Botox injection use.

EBM LEVEL

III.

A Review of Complications Due to the Use of Botulinum Toxin A for Cosmetic Indications

BACKGROUND

Botulinum toxin A (botulinum toxin A) was found to provide a wide variety of therapeutic and aesthetic benefits as one of the most potent toxins in the world. Injectable remedies, including soft tissue fillers and botulinum toxin, have become very common in wrinkling and face rejuvenation management. While these methods of treatment are relatively safe, serious side effects can occur. In this review, the complications of BoNTA are highlighted.

METHODS

A literature research considered published journal articles (clinical trials or scientific reviews). Electronic databases (PubMed, Scopus, Science Direct) were searched using key terms, and for identification of additional relevant studies, reference lists have also been examined. Only articles published in English were included in this review with a time restriction from 2000 to 2020.

RESULTS

There are various injection-related adverse effects associated (AE) with botulinum toxins such as erythema, oedema, pain, ptosis of eyelid or brow and ecchymosis. The overall majority of adverse events identified are mild and temporary.

CONCLUSION

As the use of toxins becomes increasingly more common, adverse events can be expected to increase as well. The practitioners need to be aware of such AEs, and the patients should be informed of these before undertaking such procedures.

LEVEL OF EVIDENCE III

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Use of AbobotulinumtoxinA for Cosmetic Treatments in the Neck, and Middle and Lower Areas of the Face: A Systematic Review

AbobotulinumtoxinA (aboBoNT-A) has been used for various cosmetic purposes, including minimization of moderate to severe lines, or other cosmetic indications, in the face and neck. We carried out a systematic review to identify all relevant evidence on the treatment approaches and outcomes of aboBoNT-A as a cosmetic treatment of the middle and lower areas of the face, and the neck. Embase, MEDLINE, Cochrane Library, congress proceedings and review bibliographies were searched for relevant studies. Identified articles were screened against pre-specified eligibility criteria. Of 560 unique articles identified, 10 were included for data extraction (three observational studies, 1 randomized controlled trial [with two articles] and five non-randomized trials). The articles provided data on gummy/asymmetric smile (2), marionette lines (5), masseter muscle volume (2), nasal wrinkles (2), perioral wrinkles (3) and the platysma muscle (4). All articles reporting on efficacy of aboBoNT-A demonstrated positive results, including reduction of wrinkles (5), reduction of masseter muscle (2) and degree of gummy smile (1) compared with before treatment. No serious adverse events were reported and patient satisfaction was high. In conclusion, positive findings support further research of aboBoNT-A for the middle and lower areas of the face, and in the neck, which are largely unapproved indications.

Image-guided botulinum toxin injection in the lateral abdominal wall prior to abdominal wall reconstruction surgery: review of techniques and results

Ventral hernias represent the most common complication after abdominal surgery. Loss of domain and/or large ventral hernias in patients are especially challenging for surgeons to manage, but preoperative image-guided botulinum toxin injection has emerged as an effective adjunct to abdominal wall surgery. Loss of domain is caused by chronic muscle retraction of the lateral abdominal wall and leads to an irreducible protrusion of abdominal viscera into the hernia sac. Botulinum toxin can be used in the oblique muscles as a chemical component relaxation technique to aid abdominal wall reconstruction. Intramuscular botulinum toxin injection causes functional denervation by blocking neurotransmitter acetylcholine release resulting in flaccid paralysis and elongation of lateral abdominal wall muscles, increasing the rate of fascial closure during abdominal wall reconstruction, and decreasing recurrence rates. In total, 200-300 units of onabotulinumtoxinA (Botox®) or 500 units of abobotulinumtoxinA (Dypsort®) in a 2:1 dilution with normal saline is most commonly used. Botulinum toxin can be injected with ultrasonographic, EMG, or CT guidance. Injection should be performed at least 2 weeks prior to abdominal wall reconstruction, for maximal effect during surgery. At minimum, botulinum toxin should be injected into the external and internal oblique muscles at three separate sites bilaterally for a total of six injections. Although botulinum toxin use for abdominal wall reconstruction is currently not indicated by the Food and Drug Administration, it is safe with only minor complications reported in literature.

Identification of 3-hydroxy-1,2-dimethylpyridine-4(1H)-thione as a metal-binding motif for the inhibition of botulinum neurotoxin A

Botulinum neurotoxin serotype A (BoNT/A) is an important therapeutic target owing to its extremely potent nature, but also has potential use as a biowarfare agent. Currently, no therapeutic exists to reverse the long-lasting paralysis caused by BoNT/A. Herein, we describe the identification of 3-hydroxy-1,2-dimethylpyridine-4(1H)-thione (3,4-HOPTO) as a metal binding warhead for the inhibition of BoNT/A1. An initial screen of 96 metal binding fragments identified three derivatives containing the 3,4-HOPTO scaffold to inhibit the BoNT/A1 light chain (LC) at >95% at 1 mM. Additional screening of a 3,4-HOPTO sub-library identified structure-activity relationships (SARs) between N-substituted 3,4-HOPTO derivatives and the BoNT/A1 LC. Subsequent synthesis was conducted to improve on inhibitory potency - achieving low μM biochemical IC50 values. Representative compounds were evaluated in a cellular-based assay and showed promising μM activity.

Botulinum Toxin Type A injections for pediatric spasticity: Keeping our patients informed and practices safe

Serious adverse events (serious AEs) following the therapeutic use of Botulinum Toxin Type A (BoNT-A) are infrequent. Children with pediatric spasticity often have comorbidities that can cloud causation around an adverse event (AE). If a serious AE occurs, clear documentation of information sharing and informed consent as well as the provider-patient relationship are critical to minimizing litigation risks. Reviewing the litigation that has occurred following BoNT-A for pediatric spasticity can offer insight into how providers' perspectives regarding this intervention may differ from those of the public who might serve as jurists. This article offers suggestions for content sharing during the consent process to optimize patient understanding about potential adverse events.

Potentialities of botulinum therapy in cosmetology

The desire to maintain youth as long as it possible in modern society, especially among women of working age, is primarily due to the desire to be in demand, well-groomed and attractive. Currently, there are 5 main methods that contribute to improving the condition of the skin of the face, namely: the method using professional cosmetics, chemical peels, mesotherapy, treatment with an injection of botulinum toxin type A (BTA) and intradermal implants based on hyaluronic acid. The aim of the literature review was to analyze the latest scientific data on the possibility of botulinum therapy in cosmetology. Wrinkles of open areas of the body (primarily on the face and in the decollete) have a negative effect on the emotional background and quality of life of women. In this regard, recently there has been a significant increase in demand for aesthetic medicine services, one of the areas of which is botulinum therapy (BT). Botulinum toxin type A (BTA) is a powerful neurotoxin that inhibits the release of acetylcholine in the neuromuscular junction. Injections of small doses of botulinum toxin type A into targeted mimic muscles cause their relaxation, which smoothes the underlying layer of the skin, thereby regressing mimic wrinkles. Today, according to officially approved indications, it is used in cosmetology, botulinum therapy is used to correct mimic wrinkles in the upper third of the face, drooping corners of the mouth, in the complex correction of the face oval, in the treatment of axillary and palmar hyperhidrosis. Blocking a tear mediator like acetylcholine, not only the presynaptic membranes of neuromuscular synapses are rich, but also many anatomical structures, such as glandular tissue (sweat, other glands, etc.). This commonality of the mechanism of action on various physiological processes in our body allows us to make an assumption about the great potential of botulinum therapy in the treatment of a number of diseases associated with impaired neuromuscular conduction.