1 INDICATIONS AND USAGE BOTOX is an acetylcholine release inhibitor and a neuromuscular blocking agent indicated for: Treatment of overactive bladder (OAB) with symptoms of urge urinary incontinence, urgency, and frequency, in adults who have an inadequate response to or are intolerant of an anticholinergic medication ( 1.1 ) Treatment of urinary incontinence due to detrusor overactivity associated with a neurologic condition [e.g., spinal cord injury (SCI), multiple sclerosis (MS)] in adults who have an inadequate response to or are intolerant of an anticholinergic medication ( 1.1 ) Treatment of neurogenic detrusor overactivity (NDO) in pediatric patients 5 years of age and older who have an inadequate response to or are intolerant of anticholinergic medication.

( 1.2 ) Prophylaxis of headaches in adult patients with chronic migraine (≥15 days per month with headache lasting 4 hours a day or longer) ( 1.3 ) Treatment of spasticity in patients 2 years of age and older ( 1.4 ) Treatment of cervical dystonia in adult patients, to reduce the severity of abnormal head position and neck pain ( 1.5 ) Treatment of severe axillary hyperhidrosis that is inadequately managed by topical agents in adult patients ( 1.6 ) Treatment of blepharospasm associated with dystonia in patients 12 years of age and older ( 1.7 ) Treatment of strabismus in patients 12 years of age and older ( 1.7 ) Limitations of Use Safety and effectiveness of BOTOX have not been established for: Prophylaxis of episodic migraine (14 headache days or fewer per month) ( 1.3 ) Treatment of hyperhidrosis in body areas other than axillary ( 1.6 ) 1.1 Adult Bladder Dysfunction Overactive Bladder BOTOX for injection is indicated for the treatment of overactive bladder with symptoms of urge urinary incontinence, urgency, and frequency, in adults who have an inadequate response to or are intolerant of an anticholinergic medication.

Detrusor Overactivity associated with a Neurologic Condition BOTOX is indicated for the treatment of urinary incontinence due to detrusor overactivity associated with a neurologic condition (e.g., SCI, MS) in adults who have an inadequate response to or are intolerant of an anticholinergic medication.

1.2 Pediatric Detrusor Overactivity A ssociated with a Neurologic Condition BOTOX is indicated for the treatment of neurogenic detrusor overactivity (NDO) in pediatric patients 5 years of age and older who have an inadequate response to or are intolerant of anticholinergic medication.

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3 Chronic Migraine BOTOX is indicated for the prophylaxis of headaches in adult patients with chronic migraine (≥15 days per month with headache lasting 4 hours a day or longer).

Limitations of Use Safety and effectiveness have not been established for the prophylaxis of episodic migraine (14 headache days or fewer per month) in seven placebo-controlled studies.

1.

4 Spasticity BOTOX is indicated for the treatment of spasticity in patients 2 years of age and older.

Limitations of Use BOTOX has not been shown to improve upper extremity functional abilities, or range of motion at a joint affected by a fixed contracture.

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5 Cervical Dystonia BOTOX is indicated for the treatment of adults with cervical dystonia, to reduce the severity of abnormal head position and neck pain associated with cervical dystonia.

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6 Primary Axillary Hyperhidrosis BOTOX is indicated for the treatment of severe primary axillary hyperhidrosis that is inadequately managed with topical agents.

Limitations of Use The safety and effectiveness of BOTOX for hyperhidrosis in other body areas have not been established.

Weakness of hand muscles and blepharoptosis may occur in patients who receive BOTOX for palmar hyperhidrosis and facial hyperhidrosis, respectively.

Patients should be evaluated for potential causes of secondary hyperhidrosis (e.g., hyperthyroidism) to avoid symptomatic treatment of hyperhidrosis without the diagnosis and/or treatment of the underlying disease.

Safety and effectiveness of BOTOX have not been established for the treatment of axillary hyperhidrosis in pediatric patients under age 18.

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7 Blepharospasm and Strabismus BOTOX is indicated for the treatment of strabismus and blepharospasm associated with dystonia, including benign essential blepharospasm or VII nerve disorders in patients 12 years of age and older.

6 ADVERSE REACTIONS The following adverse reactions to BOTOX (onabotulinumtoxinA) for injection are discussed in greater detail in other sections of the labeling: Spread of Toxin Effects [see Warnings and Precautions ( 5.1 )] Serious Adverse Reactions with Unapproved Use [see Warnings and Precautions ( 5.3 )] Hypersensitivity Reactions [see Contraindications ( 4 ) a nd Warnings and Precautions ( 5.4 )] Increased Risk of Clinically Significant Effects with Pre-Existing Neuromuscular Disorders [see Warnings and Precautions ( 5.5 )] Dysphagia and Breathing Difficulties [see Warnings and Precautions ( 5.6 )] Pulmonary Effects of BOTOX in Patients with Compromised Respiratory Status Treated for Spasticity or for Detrusor Overactivity Associated with a Neurologic Condition [see Warnings and Precautions ( 5.7 )] Corneal Exposure and Ulceration in Patients Treated with BOTOX for Blepharospasm [see Warnings and Precautions ( 5.8 )] Retrobulbar Hemorrhages in Patients Treated with BOTOX for Strabismus [see Warnings and Precautions ( 5.9 )] Bronchitis and Upper Respiratory Tract Infections in Patients Treated for Spasticity [se e Warnings and Precautions ( 5.10 )] Autonomic Dysreflexia in Patients Treated for Detrusor Overactivity Associated with a Neurologic Condition [see Warnings and Precautions ( 5.11 )] Urinary Tract Infections in Patients with Overactive Bladder [see Warnings and Precautions ( 5.12 )] Urinary Retention in Patients Treated for Bladder Dysfunction [see Warnings and Precautions ( 5.13 )] The most common adverse reactions (≥5% and >placebo, if applicable) are ( 6.1 ): OAB: urinary tract infection, dysuria, urinary retention Adult Detrusor Overactivity associated with a neurologic condition: urinary tract infection, urinary retention Pediatric Detrusor Overactivity associated with a neurologic condition: urinary tract infection, leukocyturia, bacteriuria Chronic Migraine: neck pain, headache Adult Spasticity: pain in extremity Pediatric Spasticity: upper respiratory tract infection Cervical Dystonia: dysphagia, upper respiratory infection, neck pain, headache, increased cough, flu syndrome, back pain, rhinitis Axillary Hyperhidrosis: injection site pain and hemorrhage, non-axillary sweating, pharyngitis, flu syndrome To report SUSPECTED ADVERSE REACTIONS, contact AbbVie at 1-800-678-1605 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, the adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice.

BOTOX and BOTOX Cosmetic contain the same active ingredient in the same formulation, but with different labeled Indications and Usage.

Therefore, adverse reactions observed with the use of BOTOX Cosmetic also have the potential to be observed with the use of BOTOX.

In general, adverse reactions occur within the first week following injection of BOTOX and, while generally transient, may have a duration of several months or longer.

Localized pain, infection, inflammation, tenderness, swelling, erythema, and/or bleeding/bruising may be associated with the injection.

Symptoms associated with flu-like symptoms (e.g., nausea, fever, myalgia) have been reported after treatment.

Needle-related pain and/or anxiety may result in vasovagal responses (including syncope, hypotension), which may require appropriate medical therapy.

Local weakness of the injected muscle(s) represents the expected pharmacological action of botulinum toxin.

However, weakness of nearby muscles may also occur due to spread of toxin [see Warnings and Precautions ( 5.1 )] .

Overactive Bladder Table 14 presents the most frequently reported adverse reactions in double-blind, placebo-controlled clinical trials for overactive bladder occurring within 12 weeks of the first BOTOX treatment.

Table 14: Adverse Reactions Reported by ≥2% of BOTOX Treated Patients and More Often than in Placebo-Treated Patients Within the First 12 Weeks after Intradetrusor Injection, in Double-Blind, Placebo-Controlled Clinical Trials in Patients with OAB Adverse Reactions BOTOX 100 Units (N=552) % Placebo (N=542) % Urinary tract infection Dysuria Urinary retention Bacteriuria Residual urine volume* 18 9 6 4 3 6 7 0 2 0 *Elevated PVR not requiring catheterization.

Catheterization was required for PVR ≥350 mL regardless of symptoms, and for PVR ≥200 mL to <350 mL with symptoms (e.g., voiding difficulty).

A higher incidence of urinary tract infection was observed in patients with diabetes mellitus treated with BOTOX 100 Units and placebo than in patients without diabetes, as shown in Table 15.

Table 15: Proportion of Patients Experiencing Urinary Tract Infection Following an Injection in Double-Blind, Placebo-Controlled Clinical Trials in OAB According to History of Diabetes Mellitus Patients with Diabet es Patients without D iabet es B OTOX 100 Units (N=81) % Placebo (N=69) % B OTOX 100 Units (N=526) % Placebo (N=516) % Urinary tract infection (UTI) 31 12 26 10 The incidence of UTI increased in patients who experienced a maximum post-void residual (PVR) urine volume ≥200 mL following BOTOX injection compared to those with a maximum PVR <200 mL following BOTOX injection, 44% versus 23%, respectively.

No change was observed in the overall safety profile with repeat dosing during an open-label, uncontrolled extension trial.

Adult Detrusor Overactivity associated with a Neurologic Condition Table 16 presents the most frequently reported adverse reactions in the double-blind, placebo-controlled studies within 12 weeks of injection for patients with detrusor overactivity associated with a neurologic condition treated with BOTOX 200 Units.

Table 16: Adverse Reactions Reported by ≥2% of BOTOX-Treated Patients and More Frequent than in Placebo-Treated Patients Within the First 12 Weeks after Intradetrusor Injection in Double-Blind, Placebo-Controlled Clinical Trials Adverse Reactions BOTOX 200 Units (N=262) % Placebo (N=272) % Urinary tract infection Urinary retention Hematuria 24 17 4 17 3 3 The following adverse reactions with BOTOX 200 Units were reported at any time following initial injection and prior to re-injection or study exit (median duration of exposure was 44 weeks): urinary tract infections (49%), urinary retention (17%), constipation (4%), muscular weakness (4%), dysuria (4%), fall (3%), gait disturbance (3%), and muscle spasm (2%).

In the Multiple Sclerosis (MS) patients enrolled in the double-blind, placebo-controlled trials, the MS exacerbation annualized rate (i.e., number of MS exacerbation events per patient-year) was 0.23 for BOTOX and 0.20 for placebo.

No change was observed in the overall safety profile with repeat dosing.

Table 17 presents the most frequently reported adverse reactions in a placebo-controlled, double-blind post-approval 52 week study with BOTOX 100 Units (Study NDO-3) conducted in MS patients with urinary incontinence due to detrusor overactivity associated with a neurologic condition.

These patients were not adequately managed with at least one anticholinergic agent and not catheterized at baseline.

The table below presents the most frequently reported adverse reactions within 12 weeks of injection.

Table 17: Adverse Reactions Reported in a Post Approval Study (NDO-3) by >2% of BOTOX Treated Patients and More Frequent than in Placebo-Treated Patients Within the First 12 Weeks after Intradetrusor Injection Adverse Reactions BOTOX 100 Unit s (N=66) % Placebo (N=78) % Urinary tract infection Bacteriuria Urinary retention Dysuria Residual urine volume* 26 9 15 5 17 6 5 1 1 1 * Elevated PVR not requiring catheterization.

Catheterization was required for PVR ≥350 mL regardless of symptoms, and for PVR ≥200 mL to <350 mL with symptoms (e.g., voiding difficulty).

The following adverse events with BOTOX 100 Units were reported at any time following initial injection and prior to re-injection or study exit (median duration of exposure was 51 weeks): urinary tract infections (39%), bacteriuria (18%), urinary retention (17%), residual urine volume* (17%), dysuria (9%), and hematuria (5%).

No difference in the MS exacerbation annualized rate (i.e., number of MS exacerbating events per patient-year) was observed (BOTOX =0, placebo =0.07).

Pediatric Detrusor Overactivity associated with a Neurologic Condition Table 18 presents the most frequently reported adverse reactions in Study 191622-120, a double-blind, parallel-group study conducted in pediatric patients with detrusor overactivity associated with a neurologic condition.

These patients were not adequately managed with at least one anticholinergic agent and were using clean intermittent catheterization at baseline [see Clinical Studies ( 14.3 )].

The table below presents the most frequently reported adverse reactions during the 12 weeks following intradetrusor administration of BOTOX 200 Units.

Table 18: Adverse Reactions Reported by ≥ 3% of BOTOX Treated Pediatric Patients within the First 12 Weeks after Intradetrusor Injection, Study 191622-120 Adverse Reactions BOTOX 200 Unit (N=30) Urinary tract infection 2 (7%) Bacteriuria 6 (20%) Leukocyturia 2 (7%) Hematuria 1 (3%) No change was observed in the overall safety profile with repeat dosing.

The most common adverse reactions in patients who received BOTOX 6 U/kg and less than a total dose of 200 U in Study 191622-120 were urinary tract infection (UTI), bacteriuria and hematuria.

Chronic Migraine In double-blind, placebo-controlled chronic migraine efficacy trials (Study 1 and Study 2), the discontinuation rate was 12% in the BOTOX treated group and 10% in the placebo-treated group.

Discontinuations due to an adverse event were 4% in the BOTOX group and 1% in the placebo group.

The most frequent adverse events leading to discontinuation in the BOTOX group were neck pain, headache, worsening migraine, muscular weakness and eyelid ptosis.

The most frequently reported adverse reactions following injection of BOTOX for chronic migraine appear in Table 19.

Table 19: Adverse Reactions Reported by ≥2% of BOTOX Treated Patients and More Frequent than in Placebo-Treated Patients in Two Chronic Migraine Double-Blind, Placebo-Controlled Clinical Trials Adverse Reactions BOTOX 155 Units-195 Units (N=687) % Placebo (N=692) % Nervous system disorders Headache Migraine Facial paresis 5 4 2 3 3 0 Eye disorders Eyelid ptosis 4 <1 Infections and Infestations Bronchitis 3 2 Musculoskeletal and connective tissue disorders Neck pain Musculoskeletal stiffness Muscular weakness Myalgia Musculoskeletal pain Muscle spasms 9 4 4 3 3 2 3 1 <1 1 1 1 General disorders and administration site conditions Injection site pain 3 2 Vascular Disorders Hypertension 2 1 Other adverse reactions that occurred more frequently in the BOTOX group compared to the placebo group at a frequency less than 1% and potentially BOTOX related include: vertigo, dry eye, eyelid edema, dysphagia, eye infection, and jaw pain.

Severe worsening of migraine requiring hospitalization occurred in approximately 1% of BOTOX treated patients in Study 1 and Study 2, usually within the first week after treatment, compared to 0.3% of placebo-treated patients.

Adult Upper Limb Spasticity The most frequently reported adverse reactions following injection of BOTOX for adult upper limb spasticity appear in Table 20.

Table 20: Adverse Reactions Reported by ≥2% of BOTOX Treated Patients and More Frequent than in Placebo-Treated Patients in Adult Upper Limb Spasticity Double-Blind, Placebo-Controlled Clinical Trials Adverse Reactions BOTOX 251 Units - 360 Units (N=115) % BOTOX 150 Units - 250 Units (N=188) % BOTOX <150 Units (N=54) % Placebo (N=182) % Gastrointestinal disorder Nausea 3 2 2 1 General disorders and administration site conditions Fatigue 3 2 2 0 Infections and infestations Bronchitis 3 2 0 1 Musculoskeletal and connective tissue disorders Pain in extremity Muscular weakness 6 0 5 4 9 2 4 1 Twenty-two adult patients, enrolled in double-blind placebo controlled studies, received 400 Units or higher of BOTOX for treatment of upper limb spasticity.

In addition, 44 adults received 400 Units of BOTOX or higher for four consecutive treatments over approximately one year for treatment of upper limb spasticity.

The type and frequency of adverse reactions observed in patients treated with 400 Units of BOTOX were similar to those reported in patients treated for upper limb spasticity with 360 Units of BOTOX.

Adult Lower Limb Spasticity The most frequently reported adverse reactions following injection of BOTOX for adult lower limb spasticity appear in Table 21.

Two hundred thirty-one patients enrolled in a double-blind placebo controlled study (Study 7) received 300 Units to 400 Units of BOTOX, and were compared with 233 patients who received placebo.

Patients were followed for an average of 91 days after injection.

Table 21: Adverse Reactions Reported by ≥2% of BOTOX Treated Patients and More Frequent than in Placebo-Treated Patients in Adult Lower Limb Spasticity Double-Blind, Placebo-Controlled Clinical Trial (Study 7) Adverse Reactions B OTOX (N=231) % Placebo (N=233) % Musculoskeletal and connective tissue disorders Arthralgia Back pain Myalgia 3 3 2 1 2 1 Infections and infestations Upper respiratory tract infection 2 1 General disorders and administration site conditions Injection site pain 2 1 Pediatric Upper Limb Spasticity The most frequently reported adverse reactions following injection of BOTOX in pediatric patients 2 to 17 years of age with upper limb spasticity appear in Table 22.

In a double-blind, placebo-controlled trial (Study 1), 78 patients were treated with 3 Units/kg of BOTOX, and 77 patients received 6 Units/kg to a maximum dose of 200 Units of BOTOX, and were compared to 79 patients who received placebo [see Clinical Studies ( 14.6 )].

Patients were followed for an average of 91 days after injection.

Table 22: Adverse Reactions Reported by ≥2% of BOTOX 6 Units/kg Treated Patients and More Frequent than in Placebo-Treated Patients in Pediatric Upper Limb Spasticity Double-Blind, Placebo-Controlled Clinical Trial (Study 1) Adverse Reactions BOTOX 6 Units/kg (N= 77 ) % BOTOX 3 Units/kg (N= 78 ) % Placebo (N=79) % Infections and infestations Upper respiratory tract infection * 17 10 9 General disorders and administration site conditions Injection site pain 4 3 1 Gastrointestinal disorders Nausea Constipation 4 3 0 0 0 1 Respiratory, thoracic and mediastinal disorders Rhinorrhea Nasal congestion 4 3 0 0 1 1 Nervous system disorders Seizure ** 5 1 0 * Includes upper respiratory tract infection and viral upper respiratory tract infection ** Includes seizure and partial seizure Pediatric Lower Limb Spasticity The most frequently reported adverse reactions following injection of BOTOX in pediatric patients 2 to 17 years of age with lower limb spasticity appear in Table 23.

In a double-blind, placebo-controlled trial (Study 2), 126 patients were treated with 4 Units/kg of BOTOX, and 128 patients received 8 Units/kg to a maximum dose of 300 Units of BOTOX, and were compared to 128 patients who received placebo [see Clinical Studies ( 14.6 ) ].

Patients were followed for an average of 89 days after injection.

Table 23: Adverse Reactions Reported by ≥2% of BOTOX 8 Units/kg Treated Patients and More Frequent than in Placebo-Treated Patients in Pediatric Lower Limb Spasticity Double-Blind, Placebo-Controlled Clinical Trial (Study 2) Adverse Reactions BOTOX 8 Units/kg (N=128) % BOTOX 4 Units/kg (N=126) % Placebo (N=128) % General disorders and administration site conditions Injection site erythema Injection site pain 2 2 0 2 0 0 Respiratory, thoracic and mediastinal disorders Oropharyngeal pain 2 0 1 Injury, poisoning and procedural complications Ligament sprain Skin abrasion 2 2 1 0 0 0 Metabolism and nutrition disorders Decreased appetite 2 0 0 Cervical Dystonia In cervical dystonia patients evaluated for safety in double-blind and open-label studies following injection of BOTOX, the most frequently reported adverse reactions were dysphagia (19%), upper respiratory infection (12%), neck pain (11%), and headache (11%).

Other events reported in 2-10% of patients in any one study in decreasing order of incidence include: increased cough, flu syndrome, back pain, rhinitis, dizziness, hypertonia, soreness at injection site, asthenia, oral dryness, speech disorder, fever, nausea, and drowsiness.

Stiffness, numbness, diplopia, ptosis, and dyspnea have been reported.

Dysphagia and symptomatic general weakness may be attributable to an extension of the pharmacology of BOTOX resulting from the spread of the toxin outside the injected muscles [see Warning s and Precautions ( 5.1 , 5.6 )] .

The most common severe adverse reaction associated with the use of BOTOX injection in patients with cervical dystonia is dysphagia with about 20% of these cases also reporting dyspnea [see Wa rnings and Precautions ( 5.1 , 5.6 )] .

Most dysphagia is reported as mild or moderate in severity.

However, it may be associated with more severe signs and symptoms [s ee Warnings and Precautions ( 5.6 )] .

Additionally, reports in the literature include a case of a female patient who developed brachial plexopathy two days after injection of 120 Units of BOTOX for the treatment of cervical dystonia, and reports of dysphonia in patients who have been treated for cervical dystonia.

Primary Axillary Hyperhidrosis The most frequently reported adverse reactions (3-10% of adult patients) following injection of BOTOX in double-blind studies included injection site pain and hemorrhage, non-axillary sweating, infection, pharyngitis, flu syndrome, headache, fever, neck or back pain, pruritus, and anxiety.

The data reflect 346 patients exposed to BOTOX 50 Units and 110 patients exposed to BOTOX 75 Units in each axilla.

Blepharospasm In a study of blepharospasm patients who received an average dose per eye of 33 Units (injected at 3 to 5 sites) of the currently manufactured BOTOX, the most frequently reported adverse reactions were ptosis (21%), superficial punctate keratitis (6%), and eye dryness (6%).

Other events reported in prior clinical studies in decreasing order of incidence include: irritation, tearing, lagophthalmos, photophobia, ectropion, keratitis, diplopia, entropion, diffuse skin rash, and local swelling of the eyelid skin lasting for several days following eyelid injection.

In two cases of VII nerve disorder, reduced blinking from BOTOX injection of the orbicularis muscle led to serious corneal exposure, persistent epithelial defect, corneal ulceration and a case of corneal perforation.

Focal facial paralysis, syncope, and exacerbation of myasthenia gravis have also been reported after treatment of blepharospasm.

Strabismus Extraocular muscles adjacent to the injection site can be affected, causing vertical deviation, especially with higher doses of BOTOX.

The incidence rates of these adverse effects in 2058 adults who received a total of 3650 injections for horizontal strabismus was 17%.

The incidence of ptosis has been reported to be dependent on the location of the injected muscles, 1% after inferior rectus injections, 16% after horizontal rectus injections and 38% after superior rectus injections.

In a series of 5587 injections, retrobulbar hemorrhage occurred in 0.3% of cases.

6.2 Immunogenicity As with all therapeutic proteins, there is a potential for immunogenicity.

The detection of antibody formation is highly dependent on the sensitivity and specificity of the assay.

Additionally, the observed incidence of antibody (including neutralizing antibody) positivity in an assay may be influenced by several factors including assay methodology, sample handling, timing of sample collection, concomitant medications, and underlying disease.

For these reasons, comparison of the incidence of antibodies to onabotulinumtoxinA in the studies described below with the incidence of antibodies in other studies or to other products may be misleading.

In a long term, open-label study evaluating 326 cervical dystonia patients treated for an average of 9 treatment sessions with the current formulation of BOTOX, 4 (1.2%) patients had positive antibody tests.

All 4 of these patients responded to BOTOX therapy at the time of the positive antibody test.

However, 3 of these patients developed clinical resistance after subsequent treatment, while the fourth patient continued to respond to BOTOX therapy for the remainder of the study.

One patient among the 445 hyperhidrosis patients (0.2%), two patients among the 380 adult upper limb spasticity patients (0.5%), and no patients among 406 migraine patients with analyzed specimens developed the presence of neutralizing antibodies.

In one Phase 3 study and the open-label extension study in patients with pediatric lower limb spasticity, neutralizing antibodies developed in 2 of 264 patients (0.8%) treated with BOTOX for up to 5 treatment cycles.

Both patients continued to experience clinical benefit following subsequent BOTOX treatments.

In overactive bladder patients with analyzed specimens from the two phase 3 studies and the open-label extension study, neutralizing antibodies developed in 0 of 954 patients (0.0%) while receiving BOTOX 100 Unit doses and 3 of 260 patients (1.2%) after subsequently receiving at least one 150 Unit dose.

Response to subsequent BOTOX treatment was not different following seroconversion in these three patients.

In detrusor overactivity associated with neurologic condition patients with analyzable specimens in the adult drug development program (including the open-label extension study), neutralizing antibodies developed in 3 of 300 patients (1.0%) after receiving only BOTOX 200 Unit doses and 5 of 258 patients (1.9%) after receiving at least one 300 Unit dose.

Following development of neutralizing antibodies in these 8 patients, 4 continued to experience clinical benefit, 2 did not experience clinical benefit, and the effect on the response to BOTOX in the remaining 2 patients is not known.

In 99 pediatric patients who had a negative baseline result for binding antibodies or neutralizing antibodies and had at least one evaluable post-baseline value from one randomized double-blind study and one double-blind extension study, no patients developed neutralizing antibodies after receiving 50 Units to 200 Units of BOTOX.

The data reflect the patients whose test results were considered positive for neutralizing activity to BOTOX in a mouse protection assay or negative based on a screening ELISA assay or mouse protection assay.

Formation of neutralizing antibodies to botulinum toxin type A may reduce the effectiveness of BOTOX treatment by inactivating the biological activity of the toxin.

The critical factors for neutralizing antibody formation have not been well characterized.

The results from some studies suggest that BOTOX injections at more frequent intervals or at higher doses may lead to greater incidence of antibody formation.

The potential for antibody formation may be minimized by injecting with the lowest effective dose given at the longest feasible intervals between injections.

6.3 Postmarketing Experience The following adverse reactions have been identified during post-approval use of BOTOX.

Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

These reactions include: abdominal pain; alopecia, including madarosis; anorexia; brachial plexopathy; denervation/muscle atrophy; diarrhea; dry eye; eyelid edema (following periocular injection); hyperhidrosis; hypoacusis; hypoaesthesia; localized muscle twitching; malaise; Mephisto sign; paresthesia; peripheral neuropathy; radiculopathy; erythema multiforme, dermatitis psoriasiform, and psoriasiform eruption; strabismus; tinnitus; and visual disturbances.

There have been spontaneous reports of death, sometimes associated with dysphagia, pneumonia, and/or other significant debility or anaphylaxis, after treatment with botulinum toxin [s ee Warnings and Precautions ( 5.4 , 5.6 )].

There have also been reports of adverse events involving the cardiovascular system, including arrhythmia and myocardial infarction, some with fatal outcomes.

Some of these patients had risk factors including cardiovascular disease.

The exact relationship of these events to the botulinum toxin injection has not been established.

New onset or recurrent seizures have also been reported, typically in patients who are predisposed to experiencing these events.

The exact relationship of these events to the botulinum toxin injection has not been established.