Overview
11 DESCRIPTION RimabotulinumtoxinB is an acetylcholine release inhibitor. RimabotulinumtoxinB is a 700 kDA botulinum toxin type B complex produced from fermentation of the bacterium Clostridium botulinum type B (Bean strain) and exists in noncovalent association with hemagglutinin and nonhemagglutinin proteins as a neurotoxin complex.
Mechanism of Action
12 CLINICAL PHARMACOLOGY 12.1 Mechanism of Action MYOBLOC blocks cholinergic transmission at the neuromuscular and salivary neuroglandular junction by inhibiting the release of acetylcholine from peripheral cholinergic nerved terminals. This inhibition occurs according to the following sequence: neurotoxin binding to cholinergic nerve terminals, internalization of the neurotoxin into the nerve terminal, translocation of the light-chain part of the molecule into the cytosol of the nerve terminal, and enzymatic cleavage of synaptic Vesicle Associated Membrane Protein (VAMP, also known as synaptobrevin), a presynaptic target protein essential for the release of acetylcholine. In both muscles and glands, impulse transmission is re-established by the formation of new nerve endings. 12.
Indications
- 1 INDICATIONS AND USAGE 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 ) Treatment of chronic sialorrhea in adults ( 1.2 ) 1.1 Cervical Dystonia MYOBLOC 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. 1.2 Chronic Sialorrhea MYOBLOC is indicated for the treatment of chronic sialorrhea in adults.
Common Doses
- Refer to label
Dosage
2 DOSAGE AND ADMINISTRATION 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 ) 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 ) 2.1 Instructions for Safe Use The potency units of MYOBLOC are specific to the preparation and assay method utilized.
Black Box Warning
WARNING: DISTANT SPREAD OF TOXIN EFFECT Postmarketing reports indicate that the effects of MYOBLOC and all botulinum toxin products may spread from the area of injection to produce symptoms consistent with botulinum toxin effects. These 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.
Contraindications
- 4 CONTRAINDICATIONS MYOBLOC is contraindicated in patients with: A known hypersensitivity to any botulinum toxin product or to any of the components in the formulation [see Warnings and Precautions (5.3) , Description (11) ] Infection at the proposed injection site(s) MYOBLOC is contraindicated in patients with: Known hypersensitivity to any botulinum toxin preparation or to any of the components in the formulation ( 4 , 5.3 ) Infection at the proposed injection site(s) ( 4 )
Side Effects
- 6 ADVERSE REACTIONS The following clinically significant adverse reactions to MYOBLOC are discussed in greater detail in other sections of the labeling: Spread of Toxin Effect [see Warnings and Precautions (5.1) ] Lack of Interchangeability Between Botulinum Toxin Products [see Warnings and Precautions (5.2) ] Hypersensitivity Reactions [see Warnings and Precautions (5.3) ] Dysphagia and Breathing Difficulties [see Warnings and Precautions (5.4) ] Human Albumin and Transmission of Viral Diseases [see Warnings and Precautions (5.
Interactions
- 7 DRUG INTERACTIONS Co-administration with aminoglycosides or other agents interfering with neuromuscular transmission may potentiate effects of MYOBLOC ( 7.1 ) Co-administration or overlapping of botulinum toxin serotypes (within 4 months) may potentiate neuromuscular paralysis ( 7.3 ) 7.1 Aminoglycosides and Other Agents Interfering with Neuromuscular Transmission Co-administration of MYOBLOC 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. 7.