Dosage & Administration
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Myobloc Prescribing Information
Postmarketing safety data from MYOBLOC and other approved botulinum toxins suggest that botulinum toxin effects may, in some cases, be observed beyond the site of local injection. The symptoms are consistent with the mechanism of action of botulinum toxin and may include asthenia, generalized muscle weakness, diplopia, blurred vision, ptosis, dysphagia, dysphonia, dysarthria, urinary incontinence, and breathing difficulties. These symptoms have been reported hours to weeks after injection. Swallowing and breathing difficulties can be life threatening and there have been reports of death related to spread of toxin effects. The risk of symptoms is probably greatest in children treated for spasticity, but symptoms can also occur in adults treated for spasticity and other conditions, and particularly in those patients who have underlying conditions that would predispose them to these symptoms. In unapproved uses, including spasticity in children and adults, and in approved indications, symptoms consistent with spread of toxin effect have been reported at doses comparable to or lower than doses used to treat cervical dystonia.
MYOBLOC is an acetylcholine release inhibitor indicated for:
- Treatment of cervical dystonia to reduce the severity of abnormal head position and neck pain associated with cervical dystonia in adults ()
1.1 Cervical DystoniaMYOBLOC is indicated for the treatment of cervical dystonia to reduce the severity of abnormal head position and neck pain associated with cervical dystonia in adults.
- Treatment of chronic sialorrhea in adults ()
1.2 Chronic SialorrheaMYOBLOC is indicated for the treatment of chronic sialorrhea in adults.
- Cervical Dystonia: for patients with demonstrated tolerance of botulinum toxin injection, recommended total dosage is 2,500 Units to 5,000 Units divided among effected muscles ()
2.2 Dosing for Cervical DystoniaThe recommended initial dosage of MYOBLOC for cervical dystonia patients with a prior history of tolerating botulinum toxin injections is 2,500 Units to 5,000 Units divided among affected muscles
[see Clinical Studies (14.1)]. Patients without a prior history of tolerating botulinum toxin injections should receive a lower initial dosage[see Adverse Reactions (6.1)]. Subsequent dosing should be determined by the patient's individual response. MYOBLOC should be administered by physicians familiar with and experienced in the assessment and management of patients with cervical dystonia.The duration of effect in patients responding to MYOBLOC treatment for cervical dystonia has been observed in studies to be between 12 and 16 weeks at doses of 5,000 Units or 10,000 Units
[see Clinical Studies (14.1)]. - Chronic Sialorrhea: recommended dosage is 1,500 Units to 3,500 Units; 500 Units to 1,500 Units per parotid gland and 250 Units per submandibular gland; no more frequent than every 12 weeks ()
2.3 Dosing for Chronic SialorrheaDosing InformationThe recommended dosage of MYOBLOC for chronic sialorrhea is 1,500 Units to 3,500 Units, divided among the parotid and submandibular glands (Table 1). Patient response to treatment should be considered when determining subsequent MYOBLOC dosage
[see Clinical Studies (14.2)]. The typical duration of effect of each treatment is up to 3 months; however, the effect may vary in individual patients. The frequency of MYOBLOC repeat treatments should be determined by clinical response but should generally be no more frequent than every 12 weeks.Table 1: Dosing by Gland for Chronic Sialorrhea in Adults Gland Recommended Dosage Parotid 500 Units to 1,500 Units per gland Submandibular 250 Units per gland Administration InformationA suitable sterile needle (e.g., 30-gauge, 0.5 inch) should be used for intra-salivary gland administration.
Figure 1: Glands for Injection in Chronic SialorrheaGuidelines for locating salivary glands using anatomical landmarks (Figure 1):
- 1. To inject the parotid gland, bisect the distance between the tip of the tragus (Site A) and the angle of the mandible (Site B). Inject one finger breadth anterior to this site (Injection Site 1).
- 2. To inject the submandibular gland, bisect the distance between the angle of the mandible (Site B) and the tip of the chin (Site C). Inject one finger breadth medial to the inferior surface of the point of bisection (Injection Site 2).
In clinical studies, MYOBLOC was injected using anatomical landmarks to localize the salivary glands, or using ultrasound guidance for gland location. Both methods produced similar reduction in the unstimulated salivary flow rate.
Figure 1
MYOBLOC is a clear and colorless to light-yellow solution available as:
- Injection: 2,500 Units/0.5 mL in a single-dose vial
- Injection: 5,000 Units/mL in a single-dose vial
- Injection: 10,000 Units/2 mL (5,000 Units/mL) in a single-dose vial
There are no adequate data on the developmental risks associated with the use of MYOBLOC in pregnant women. No developmental toxicity was observed in pregnant rats administered MYOBLOC by intramuscular injection during gestation and lactation, at doses producing maternal toxicity.
In the U.S. general population, the background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively. The background risk of major birth defects and miscarriage for the indicated population is unknown.
MYOBLOC is contraindicated in patients with:
- A known hypersensitivity to any botulinum toxin product or to any of the components in the formulation [see,
5.3 Hypersensitivity ReactionsSerious hypersensitivity reactions have been reported with botulinum toxin products. Angioedema, urticaria, and rash have occurred with MYOBLOC treatment
[see Adverse Reactions (6.3)].Hypersensitivity reactions can also include anaphylaxis, serum sickness, soft tissue edema, and dyspnea. If serious and/or immediate hypersensitivity reactions occur, discontinue further injection of MYOBLOC and institute appropriate medical therapy immediately. The use of MYOBLOC in patients with a known hypersensitivity to any botulinum neurotoxin or to any of the excipients (human albumin, sucrose), could lead to a life-threatening allergic reaction[see Contraindications (4), Adverse Reactions (6.3)].]11 DESCRIPTIONRimabotulinumtoxinB is an acetylcholine release inhibitor. RimabotulinumtoxinB is a 700 kDA botulinum toxin type B complex produced from fermentation of the bacterium
Clostridium botulinumtype B (Bean strain) and exists in noncovalent association with hemagglutinin and nonhemagglutinin proteins as a neurotoxin complex. The neurotoxin complex is recovered from the fermentation process and purified through a series of precipitation and chromatography steps.MYOBLOC (rimabotulinumtoxinB) injection is a sterile, preservative-free, clear and colorless to light-yellow solution in a single-dose vial for intramuscular or intraglandular use. Each vial contains 2,500 Units/0.5 mL; 5,000 units/mL; or 10,000 Units/2 mL of rimabotulinumtoxinB at a concentration of 5,000 Units/mL at approximately pH 5.6.
Each 2,500 Units/0.5 mL vial of MYOBLOC contains 2,500 Units rimabotulinumtoxinB, 0.235 mg albumin human, 2.9 mg sodium chloride and 1.35 mg sodium succinate.
Each 5,000 Units/mL vial of MYOBLOC contains 5,000 Units rimabotulinumtoxinB, 0.47 mg albumin human, 5.8 mg sodium chloride and 2.7 mg sodium succinate.
Each 10,000 Units/2 mL vial of MYOBLOC contains 10,000 Units rimabotulinumtoxinB, 0.94 mg albumin human, 11.6 mg sodium chloride and 5.4 mg sodium succinate.
One unit of MYOBLOC corresponds to the calculated median lethal intraperitoneal dose (LD50) in mice. The method for performing the assay is specific to Solstice Neurosciences' manufacture of MYOBLOC. Due to differences in specific details such as the vehicle, dilution scheme and laboratory protocols for various mouse LD50 assays, Units of biological activity of MYOBLOC cannot be compared to or converted into Units of any other botulinum toxin or any toxin assessed with any other specific assay method. Therefore, differences in species sensitivities to different botulinum neurotoxin serotypes preclude extrapolation of animal dose-activity relationships to human dose estimates. The specific activity of MYOBLOC ranges between 70 to 130 Units/ng.
- Infection at the proposed injection site(s)