Botulinum toxin A (Dysport®): in dystonias and focal spasticity

Dysport?, a formulation of botulinum toxin A, blocks acetylcholine release at neuromuscular junctions causing denervation and temporary muscle paralysis. It is used to treat several medical conditions, including dystonias and focal spasticity. Subcutaneous Dysport? was effective in improving functional disability in adults with blepharospasm in a placebo-controlled trial with 16 weeks' follow-up, and in adults with hemifacial spasm in case series. Similarly, intramuscular Dysport? was effective in improving symptoms of cervical dystonia in adults, focal spasticity in adults with post-stroke upper limb spasticity and dynamic equinus spasticity in paediatric patients with cerebral palsy in placebo-controlled trials with up to 20 weeks' follow-up. However, in two 12-week, placebo-controlled trials in adults with focal lower limb spasticity (spastic equinovarus deformity after stroke and hip adductor spasticity associated with multiple sclerosis) intramuscular Dysport? had limited efficacy. Available longer-term data indicated that Dysport? treatment was effective over several treatment cycles in patients with cervical dystonia or upper limb spasticity. Dysport? was generally well tolerated in patients with dystonias or focal spasticity. Most adverse events were mild to moderate and transient.     

Botulinum toxin B: a review of its therapeutic potential in the management of cervical dystonia

Botulinum toxins are well known as the causative agents of human botulism food poisoning. However, in the past two decades they have become an important therapeutic mainstay in the treatment of dystonias including cervical dystonia, a neurological disorder characterised by involuntary contractions of the cervical and/or shoulder muscles. The toxins inhibit acetylcholine release from neuromuscular junctions, producing muscle weakness when injected into dystonic muscles. Data from three double-blind, randomised, placebo-controlled trials demonstrate that botulinum toxin B effectively reduces the severity, disability and pain of cervical dystonia. In two of the trials, mean Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS)-Total score at week 4 (primary efficacy measure) after botulinum toxin B 10 000U was reduced by 11.7 (25%) or 11 (21%) compared with baseline. These changes were significantly greater than those obtained with placebo [4.3 (10%) or 2 (4%)] and were generally similar in patients who were responsive or resistant to botulinum toxin A. Statistically significant benefits compared with placebo were also evident for a range of other efficacy parameters including TWSTRS-Severity, -Pain and -Disability subscales, patient- assessed pain and patient-/physician-assessed global improvement ratings. In another trial, the percentage of patients with botulinum toxin A-resistant or -responsive cervical dystonia who had a > or =20% improvement in the TWSTRS-Total score between baseline and week 4 was significantly higher with botulinum toxin B 2500 to 10 000U (58 to 77%) than with placebo (27%). Overall, botulinum toxin B was generally well tolerated. The most frequently reported treatment-related adverse events were dry mouth and dysphagia. Most adverse events in patients receiving botulinum toxin B were mild or moderate; no serious adverse events or laboratory abnormalities were associated with the use of botulinum toxin B and, where reported, no patients discontinued from any of the clinical trials as a result of adverse events. CONCLUSIONS: Botulinum toxin B has shown clinical efficacy in patients with cervical dystonia at doses up to 10 000U and is generally well tolerated. Its efficacy extends to patients who are resistant to botulinum toxin A. Although the potential for secondary resistance to botulinum toxin B remains unclear, it may occur less than with botulinum toxin A because methods for manufacturing commercially available botulinum toxin B do not include lyophilisation and the product does not require reconstitution before use. As injection with botulinum toxin is generally considered the treatment of choice for patients with cervical dystonia, botulinum toxin B should be considered a potential treatment option in this setting.     

Botulinum toxin type A and dynamic equinus in children with cerebral palsy: new indication. Better than repeat casts

(1) Botox degrees , a product based on type A botulinum toxin, has received a new licensed indication in the local treatment of dynamic equinus in children with spasticity due to cerebral palsy. (2) Three placebo-controlled trials show that intramuscular injections of type A botulinum toxin reduce spastic equinus and substantially improve walking for at least 3 months. Two small trials, each involving 20 children, show no difference in effects between type A botulinum toxin and successive stretching casts. (3) In this setting the risk of adverse effects is smaller with type A botulinum toxin than with stretching casts. (4) Treatment with type A botulinum toxin is costly.     

Unlabeled uses of botulinum toxins: a review, part 1.

PURPOSE: Efficacy and safety data regarding the unlabeled uses of botulinum toxins are reviewed, and the pharmacology, adverse effects, and characteristics of commercially available botulinum toxins are discussed. SUMMARY: More than 300 articles have been published on the use of botulinum toxins, particularly botulinum toxin type A, to treat conditions characterized by excessive smooth or skeletal muscle spasticity. Botulinum toxins are synthesized by Clostridium botulinum and cause temporary local paralysis of the injected muscle by inhibiting acetylcholine release at the neuromuscular junction. While botulinum toxins have Food and Drug Administration-approved labeling to treat a limited number of spasticity disorders, including cervical dystonia and blepharospasm, the toxins have more than 50 reported therapeutic uses. Among these uses, the most rigorously studied indications include achalasia, essential tremors, palmar hyperhidrosis, chronic anal fissures, headache prophylaxis, and limb spasticity. The main adverse effects of the toxins are pain and erythema at the injection site, although unintended paralysis of muscles adjacent to the site of toxin injection may also occur. CONCLUSION: Clinical studies support the use of botulinum toxins for certain conditions, although more studies are needed to establish the role of the drug relative to conventional therapies and to determine patient predictors of response. Although botulinum toxins are generally well tolerated, a patient-specific risk-benefit assessment should precede any decision to use them for unlabeled indications.     

Unlabeled uses of botulinum toxins: a review, part 2.

PURPOSE: Efficacy and safety data regarding the unlabeled uses of botulinum toxins are reviewed, and the pharmacology, adverse effects, and characteristics of commercially available botulinum toxins are discussed. SUMMARY: More than 300 articles have been published on the use of botulinum toxins, particularly botulinum toxin type A, to treat conditions characterized by excessive smooth or skeletal muscle spasticity. Botulinum toxins are synthesized by Clostridium botulinum and cause temporary local paralysis of the injected muscle by inhibiting acetylcholine release at the neuromuscular junction. While botulinum toxins have Food and Drug Administration-approved labeling to treat a limited number of spasticity disorders, including cervical dystonia and blepharospasm, the toxins have more than 50 reported therapeutic uses. Among these uses, the most rigorously studied indications include achalasia, essential tremors, palmar hyperhidrosis, chronic anal fissures, headache prophylaxis, and limb spasticity. The main adverse effects of the toxins are pain and erythema at the injection site, although unintended paralysis of muscles adjacent to the site of toxin injection may also occur. CONCLUSION: Clinical studies support the use of botulinum toxins for certain conditions, although more studies are needed to establish the role of the drug relative to conventional therapies and to determine patient predictors of response. Although botulinum toxins are generally well tolerated, a patient-specific risk-benefit assessment should precede any decision to use them for unlabeled indications.     

Spasticity associated with cerebral palsy in children: guidelines for the use of botulinum A toxin

Botulinum A toxin produces selective and reversible chemodenervation that can be employed to balance muscle forces across joints in children with cerebral palsy (CP). Currently, there are two commercially available botulinum A toxin formulations (BOTOX) and Dysport). The amount of botulinum A toxin required depends upon the number of muscles that are targeted, and the size of the patient. In order to achieve adequate chemodenervation with botulinum A toxin, the following conditions must be met: (i) a sufficient number of units of toxin must be injected in order to neutralize neuromuscular junction (NMJ) activity; (ii) an appropriate drug volume is required in order to optimize the delivery of the toxin to the NMJs; and (iii) localization of the injecting needle through the fascia of the target muscle is necessary. Localization of the injection may be facilitated by active electromyography, ultrasonography, palpation of the muscle belly, and/or use of anatomic landmarks. Botulinum A toxin injections are indicated for use in pediatric patients with CP to: (i) improve motor function by balancing muscle forces across joints; (ii) improve health-related quality of life by decreasing spasticity and/or decreasing caregiver burden; (iii) decrease pain from spasticity; (iv) enhance self-esteem by diminishing inappropriate motor responses; and (v) provide a presurgical diagnostic tool. Following intramuscular injections of botulinum A toxin, short-term benefits of reduced spasticity are observed in approximately 70-82% of children. The intermediate term (1-2 years) efficacy rate is approximately 50%. The most common deformity treated with toxin injections in pediatric patients with CP is equinus foot deformity. However, efficacy of toxin injections for the management of crouched gait, pelvic flexion contracture, cervical spasticity, seating difficulties, and upper extremity deformity also has been documented. In addition, toxin injections have been shown to manage painful muscle spasticity associated with surgery or application of casts and painful cervical spasticity with or without dystonia. Toxin injections can also be used as a diagnostic tool to determine the appropriateness of other interventions by observing the muscle response to the injection in order to gain additional information for the development of a treatment plan. Botulinum A toxin, when used in appropriate doses, is well tolerated.     

Botulinum toxin type B: a new injectable treatment for cervical dystonia

Cervical dystonia (CD) causes involuntary muscle spasms and is often associated with pain. Recently, botulinum toxin type B (BTX-B) (Myobloc?, Elan South San Francisco, CA, USA) was approved for general use in the treatment of CD in the USA. In two large pivotal trials, BTX-B was found to be safe and effective in decreasing the movements, pain and disability associated with CD. Benefits were noted both in patients who no longer respond and in those who continue to respond to botulinum toxin type A (BTX-A). BTX-B offers an additional therapeutic option for patients with CD.     

Botulinum toxin treatment of adult spasticity : a benefit-risk assessment.

Injections of botulinum toxin have revolutionised the treatment of focal spasticity. Before their advent, the medical treatment for focal spasticity involved oral anti-spasticity drugs, which had decidedly non-focal adverse effects, and phenol injections. Phenol injections could be difficult to perform, could cause sensory complications and had effects that were of uncertain duration and magnitude. Furthermore, few neurologists knew how to perform them as they were mostly the province of rehabilitation specialists. Botulinum toxin can produce focal, controllable muscle weakness of predictable duration, without sensory adverse effects.Randomised clinical trials (RCTs) involving patients with spasticity resulting from a variety of diseases (mainly stroke and multiple sclerosis) have clearly shown that botulinum toxin type A (Dysport and Botox) can temporarily (for approximately 3 months) reduce spastic hypertonia in the elbow, wrist and finger flexors of the upper limbs, and the hip adductors and ankle plantar flexors in the lower limbs. The clinical benefits from this reduction of neurological impairment are best shown in the upper limb, with less disability of passive function and reduced caregiver burden. In the lower limbs, there is improved perineal hygiene from hip adductor injections. The benefits of reducing ankle plantar flexor tone are less well established. Pain is also reduced, possibly by mechanisms other than muscle weakness. Improved active function has not yet been clearly demonstrated in RCTs, only in open-label trials. The safety of botulinum toxin-A is impressive, with minimal (mainly local) adverse effects.There are little data on the use of botulinum toxin type B (Myobloc or Neurobloc) in spasticity and the only RCT that has examined this did not show tone reduction; dry mouth appeared to be a very common adverse effect. There are also very little data to allow a benefit-risk comparison of phenol and botulinum toxin injections; each have their clinical and technical advantages and disadvantages, and phenol is much less costly than botulinum toxin.     

Clinical profile of botulinum toxin A in patients with chronic headaches and cervical dystonia: a prospective, open-label, longitudinal study conducted in a naturalistic clinical practice setting

BACKGROUND AND OBJECTIVES: Some evidence for the efficacy of botulinum toxin A as a preventive treatment for chronic primary headaches has been reported in randomized, controlled clinical studies. This study investigated the clinical profile of botulinum toxin A in a naturalistic clinical practice setting in a population of patients with cervical dystonia associated with chronic headache and a history of migraine. METHODS: This was a prospective, open-label, longitudinal study. Following a prospective run-in period, eligible patients were given three sets of botulinum toxin A injections at 8- to 12-week intervals over a 16- to 24-week period and were monitored for 3 months after the final injections. Efficacy was assessed in terms of headache-related disability (using the Migraine Disability Assessment [MIDAS] questionnaire), pain and emotional function (using the Short Pain Inventory [SPI]), quality of life (QOL, using the Short-Form-36 [SF-36] questionnaire) and patient-assessed headache frequency and severity, and medication use and its effectiveness. Safety was assessed as adverse events. The primary endpoint was the change in MIDAS score from baseline following treatment with botulinum toxin A. RESULTS: Twenty-four patients took part in the study and 17 (71%) completed the study. There were significant improvements in headache-related disability (MIDAS score), pain and emotional function (SPI), QOL (SF-36), headache frequency and medication use following treatment with botulinum toxin A (p < 0.05 for all endpoints). An efficacy response occurred within 8 weeks of treatment initiation and was maintained throughout the study duration. Botulinum toxin A was generally well tolerated. CONCLUSIONS: This study demonstrated that botulinum toxin A is an effective and well tolerated preventive treatment for chronic headache in patients with cervical dystonia and a history of migraine. These results warrant further investigation in a large, randomized, controlled study.     

Effects of Botulinum Toxin Type A on Pain among Trigeminal Neuralgia,Myofascial Temporomandibular Disorders,and Oromandibular Dystonia

The differences in analgesic effects of botulinum toxin type A were compared in 28 patients with trigeminal neuralgia, 53 patients with myofascial temporomandibular disorders, and 89 patients with the jaw closing oromandibular dystonia. The patients were treated by injection of botulinum toxin type A into the masseter, temporalis, medial pterygoid, and other muscles based on the symptoms of each patient. The pain severity was evaluated using the visual analog scale, pain frequency, and pain scale of the oromandibular dystonia rating scale. Botulinum toxin injection was performed 1068 times in all patients without significant adverse effects. The visual analog, pain frequency, and pain scales at baseline were reduced (p < 0.001) after two, four, eight, and 12 weeks after the first botulinum toxin therapy and at the endpoint. The effects differed significantly (p < 0.001) among the groups (repeated-measures analysis of variance). The mean improvement (0%, no effect; 100%, complete recovery) at the endpoint was 86.8% for trigeminal neuralgia, 80.8% for myofascial pain, and 75.4% for oromandibular dystonia. Injection of the botulinum toxin can be a highly effective and safe method to treat trigeminal neuralgia, myofascial pain, and oromandibular dystonia.     

Alternative use of botulinum toxin in urology

Botulinum toxin A is used in the treatment of lower urinary tract symptoms due to detrusor sphincter dysynergia and detrusor hyper-reflexia (neurogenic detrusor deficiency). The toxin acts by producing paralysis of muscle tissue and has been shown to be safe and effective in the treatment of conditions caused by increased muscle tonicity and spasticity. Here the literature is reviewed chronologically, the established and emerging indications for the urological use of botulinum toxin evaluated and future applications are also considered.     

Alternative use of botulinum toxin in urology

Botulinum toxin A is used in the treatment of lower urinary tract symptoms due to detrusor sphincter dysynergia and detrusor hyper-reflexia (neurogenic detrusor deficiency). The toxin acts by producing paralysis of muscle tissue and has been shown to be safe and effective in the treatment of conditions caused by increased muscle tonicity and spasticity. Here the literature is reviewed chronologically, the established and emerging indications for the urological use of botulinum toxin evaluated and future applications are also considered.     

Treatment of focal dystonias with botulinum neurotoxin

This is a review on the use of injections of botulinum toxin for the treatment of focal dystonias. Disorders covered include cranial dystonia, cervical dystonia, spasmodic dysphonia, and focal hand dystonia. Considered are clinical aspects, alternative treatment strategies and principles of use of botulinum toxin injections.     

Botulinum toxin A treatment of adult upper and lower limb spasticity

This article discusses the treatment of spasticity with botulinum toxin A as a new approach in the neurological rehabilitation of patients after stroke. Clinical studies have been reviewed to provide information about target groups, technical aspects and the advantages and disadvantages of treating spasticity with botulinum toxin A. Open and controlled studies showed that the intramuscular injection of Dysport 500 to 1,500U or Botox 100 to 300U could reversibly relieve upper limb flexor and lower limb extensor spasticity. A reduced muscle tone, pain relief, better hand hygiene and improved walking function were the main benefits. Patients tolerated the treatment well. Activity or, if not possible, electrical stimulation of the injected muscles may enhance the effectiveness of the costly toxin. Serial casting is another option. With respect to the action of botulinum toxin A, it is suggested that the effect of the toxin could be mediated by paresis of both the extrafusal and intrafusal muscle fibres, thereby altering the afferent discharge in the muscle.     

High Doses of Botulinum Toxin Type A for the Treatment of Post-Stroke Spasticity: Rationale for a Real Benefit for the Patients

In the past few years, there was a great interest in the use of higher doses of botulinum toxin type A, especially in case of upper and lower limb severe spasticity. To date, only one prospective, non-randomized, single-arm, multicenter, open-label, dose-titration study with the employment of incobotulinum toxin up to 800 U has been published, and the authors investigated safety and tolerability. Other researches showed efficacy in spasticity reduction, but there is a lack of evidence about the reasons to use high doses of botulinum toxin. This short communication highlights the benefits of higher doses for subjects with upper and lower limb spasticity.     

Botulinum toxin type A for migraine. First, do no harm

Headache prevention in adults with chronic migraine is based first on oral drug therapy, preferably with propranolol, and on tapering off possible analgesic overuse. Botulinum toxin type A injections in head and neck muscles is now authorised for this purpose in the United Kingdom. It has been used off label for several years. Clinical evaluation in this indication is based on two placebo-controlled double-blind trials with identical designs. A total of 1384 patients underwent two sessions of intramuscular injections of botulinum toxin type A or placebo, 3 months apart, into at least 31 specific sites in the head and neck. Compared to baseline, patients who received botulinum toxin in one trial (but not in the other) experienced a statistically significant reduction in headache frequency at the end of the study, but the results are undermined by methodological issues. Botulinum toxin type A has not been compared with preventive oral therapy. An inherently unreliable indirect comparison suggests that botulinum toxin type A is clearly less effective than oral propranolol. In its other approved indications, botulinum toxin type A has been linked to deaths and muscle paralysis distant from the injection site, leading to swallowing difficulties and respiratory disorders. Some patients enrolled in clinical trials of botulinum toxin type A experienced transient worsening of their migraine and headache (9.3%, versus 5.8% of patients receiving placebo injections), exaggerated paralytic effects, and muscle pain and stiffness. In practice, given its uncertain efficacy, at best only modest, botulinum toxin type A is simply too risky a treatment for migraine. It is better to focus on fine tuning of standard prophylaxis.     

The safety and tolerability of botulinum toxins for the treatment of cervical dystonia

The use of botulinum toxin to treat cervical dystonia (CD) has dramatically improved the quality of life of patients with this disabling, often painful disease. Two forms of type A toxin (BOTOX and Dysport) and one form of type B toxin (MyoBloc) are available in some parts of the world to treat patients with CD. The literature supports the efficacy of each in reducing the pain and movement of cervical dystonia. The dosing and side effects vary between the toxins. The potential availability of several forms of toxin will allow physicians to offer further treatment options to patients with CD. However, it is incumbent on the treating physicians to have a working knowledge of the different serotypes, different doses used of each formulation of each serotype, the side effect profile of each product and the potential for anti-body formation for each form of toxin.     

Safety profile of iloperidone in the treatment of schizophrenia

The use of botulinum toxin to treat cervical dystonia (CD) has dramatically improved the quality of life of patients with this disabling, often painful disease. Two forms of type A toxin (BOTOX® and Dysport®) and one form of type B toxin (MyoBloc®) are available in some parts of the world to treat patients with CD. The literature supports the efficacy of each in reducing the pain and movement of cervical dystonia. The dosing and side effects vary between the toxins. The potential availability of several forms of toxin will allow physicians to offer further treatment options to patients with CD. However, it is incumbent on the treating physicians to have a working knowledge of the different serotypes, different doses used of each formulation of each serotype, the side effect profile of each product and the potential for anti-body formation for each form of toxin.     

Management of bladder, prostatic and pelvic floor disorders with botulinum neurotoxin

Since its introduction in the late 1970s for the treatment of strabismus and blepharospasm, botulinum toxin (BoNT) has been increasingly used in the interventional treatment of several other disorders characterized by excessive or inappropriate muscle contractions. The use of this pluripotential agent has extended to a plethora of conditions including: focal dystonia; spasticity; inappropriate contraction in most sphincters of the body such as those associated with spasmodic dysphonia, esophageal achalasia, chronic anal fissure, and vaginismus; eye movement disorders; other hyperkinetic disorders including tics and tremors; autonomic disorders such as hyperhidrosis; genitourinary disorders such as overactive and neurogenic bladder, non-bacterial prostatitis and benign prostatic hyperplasia; and aesthetically undesirable hyperfunctional facial lines. In addition, BoNT is being investigated for the control of the pain, and for the management of tension or migraine headaches and myofascial pain syndrome. BoNT injections have several advantages over drugs and surgical therapies in the management of intractable or chronic disease. Systemic pharmacologic effects are rare; permanent destruction of tissue does not occur. Graded degrees of relaxation may be achieved by varying the dose injected; most adverse effects are transient. Finally, patient acceptance is high. In this paper, clinical experience over the last years with BoNT in urological impaired patients will be illustrated. Moreover, this paper presents current data on the use of BoNT to treat pelvic floor disorders.     

Botulinum toxin type A for treatment of refractory gastroparesis.

PURPOSE: The clinical efficacy and adverse reactions of botulinum toxin type A for refractory gastroparesis are discussed. SUMMARY: Botulinum toxin type A does not have an FDA-labeled indication for the treatment of gastroparesis, but it has been evaluated for this indication in several small case studies and open-label trials. The dose of botulinum toxin type A ranged from 80 to 200 units, injected directly into the pylorus in patients refractory to standard management. One study found both clinical and scintigraphic improvements in patients with diabetic gastroparesis that were maintained for at least six weeks. In another study in patients with diabetic gastroparesis, the agent decreased gastric emptying time and improved nausea, vomiting, and abdominal pain but did not significantly improve patients' overall quality of life. In a study consisting of a chart review, 27 (43%) of 63 patients responded to botulinum toxin type A and 36 patients (57%) did not. Responders had a mean duration of response of 5.1 months. A study in patients with idiopathic gastroparesis found improved gastric emptying and improved symptom scores in most cases. Botulinum toxin type A is contraindicated in patients with infection at the injection site or hypersensitivity to any of the ingredients. There have been rare reports of serious hypersensitivity reactions. Dysphagia is common. CONCLUSION: Botulinum toxin type A may be effective in the management of refractory gastroparesis; however, large, double-blind, placebo-controlled trials are needed to confirm this.