The following adverse reactions to BOTOX Cosmetic (onabotulinum toxin A) For Injection are discussed in greater detail in other sections of the labeling:

• Spread of Toxin Effects [see WARNINGS AND PRECAUTIONS]
• Hypersensitivity [see CONTRAINDICATIONS and WARNINGS AND PRECAUTIONS]
• Dysphagia and Breathing Difficulties in Treatment of Cervical Dystonia [see WARNINGS AND PRECAUTIONS]

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 have different labeled Indications and Usage. Therefore, adverse events observed with the use of BOTOX also have the potential to be observed with the use of BOTOX Cosmetic.

In general, adverse reactions occur within the first week following injection of BOTOX Cosmetic 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. Needle-related pain and/or anxiety may result in vasovagal responses (including e.g., 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].

Glabellar Lines

In clinical trials of BOTOX Cosmetic the most frequently reported adverse events following injection of BOTOX Cosmetic were headache*, respiratory infection*, flu syndrome*, blepharoptosis and nausea.

Less frequently occurring ( < 3%) adverse reactions included pain in the face, erythema at the injection site*, paresthesia* and muscle weakness. While local weakness of the injected muscle(s) is representative of the expected pharmacological action of botulinum toxin, weakness of adjacent muscles may occur as a result of the spread of toxin. These events are thought to be associated with the injection and occurred within the first week. The events were generally transient but may last several months or longer. (* incidence not different from Placebo)

The data described in Table 2 reflect exposure to BOTOX Cosmetic in 405 subjects aged 18 to 75 who were evaluated in the randomized, placebo-controlled clinical studies to assess the use of BOTOX Cosmetic in the improvement of the appearance of glabellar lines [see Clinical Studies]. Adverse events of any cause were reported for 44% of the BOTOX Cosmetic treated subjects and 42% of the placebo treated subjects. The incidence of blepharoptosis was higher in the BOTOX Cosmetic treated arm than in placebo (3% vs. 0).

In the open-label, repeat injection study, blepharoptosis was reported for 2% (8/373) of subjects in the first treatment cycle and 1% (4/343) of subjects in the second treatment cycle. Adverse events of any type were reported for 49% (183/373) of subjects overall. The most frequently reported of these adverse events in the open-label study included respiratory infection, headache, flu syndrome, blepharoptosis, pain and nausea.

Table 2: Adverse Events Reported at Higher Frequency ( > 1%) in the BOTOX Cosmetic Group Compared to the Placebo Group

Immunogenicity

Treatment with botulinum toxins may result in the formation of neutralizing antibodies that may reduce the effectiveness of subsequent treatments by inactivating biological activity of the toxin.

The rate of formation of neutralizing antibodies in patients receiving BOTOX Cosmetic has not been well studied. The results from some studies suggest that botulinum toxin 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. The critical factors for neutralizing antibody formation have not been well characterized.

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 BOTOX Cosmetic with the incidence of antibodies to other products may be misleading.

Post-marketing Experience

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.

There have been spontaneous reports of death, sometimes associated with dysphagia, pneumonia, and/or other significant debility or anaphylaxis, after treatment with botulinum toxin [see WARNINGS AND PRECAUTIONS].

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.

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

The following adverse reactions by System Organ Class have been identified during post-approval use of BOTOX/BOTOX Cosmetic:

Ear and labyrinth disorders

Hypoacusis; tinnitus; vertigo

Eye disorders

Diplopia; strabismus; visual disturbances; vision blurred

Gastrointestinal disorders

Abdominal pain; diarrhea; dry mouth; nausea; vomiting

General disorders and administration site conditions

Denervation; malaise; pyrexia

Metabolism and nutrition disorders

Anorexia

Musculoskeletal and connective tissue disorders

Muscle atrophy; myalgia

Nervous system disorders

Brachial plexopathy; dysarthria; facial palsy; hypoaesthesia; localized numbness; myasthenia gravis; paresthesia; peripheral neuropathy; radiculopathy; syncope

Respiratory, thoracic and mediastinal disorders

Aspiration pneumonia; dyspnea; respiratory depression and/or respiratory failure

Skin and subcutaneous tissue disorders

Alopecia, including madarosis; hyperhidrosis; pruritus; skin rash (including erythema multiforme, dermatitis psoriasiform, and psoriasiform eruption)

Read the Botox Cosmetic (onabotulinumtoxina for injection) Side Effects Center for a complete guide to possible side effects »

No formal drug interaction studies have been conducted with BOTOX Cosmetic (onabotulinum toxin A) For Injection.

Aminoglycosides and Other Agents Interfering with Neuromuscular Transmission

Co-administration of BOTOX Cosmetic and aminoglycosides or other agents interfering with neuromuscular transmission (e.g., curare-like compounds) should only be performed with caution as the effect of the toxin may be potentiated.

Anticholinergic Drugs

Use of anticholinergic drugs after administration of BOTOX Cosmetic may potentiate systemic anticholinergic effects.

Other Botulinum Neurotoxin Products

The effect of administering different botulinum neurotoxin products at the same time or within several months of each other is unknown. Excessive neuromuscular weakness may be exacerbated by administration of another botulinum toxin prior to the resolution of the effects of a previously administered botulinum toxin.

Muscle Relaxants

Excessive weakness may also be exaggerated by administration of a muscle relaxant before or after administration of BOTOX Cosmetic.

Last reviewed on RxList: 11/26/2012
This monograph has been modified to include the generic and brand name in many instances.