rimabotulinumtoxinB (Rx)

Brand and Other Names:Myobloc
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Dosing & Uses


Dosage Forms & Strengths

injectable solution

  • 5000units/mL (single-dose vial)

Cervical Dystonia

Indicated for cervical dystonia to reduce the severity of abnormal head position and neck pain associated with cervical dystonia

Prior botulinum toxin injection: 2500-5000 units IM, divided among affected muscles

No prior botulinum toxin injection: Lower initial dose

Determine subsequent dosing based on patient’s individual response

Duration of effect observed in studies between 12-16 weeks at doses 5,000-10,000 units

Chronic Sialorrhea

Indicated for chronic sialorrhea

1,500-3,500 units, divided among parotid and submandibular glands via intraglandular administration

Parotid gland: 500-1,500 units/gland

Submandibular gland: 250 units/gland

Consider patient response to treatment when determining frequency and dose of subsequent treatments; no more frequent than q12Weeks

Duration of effect of each treatment is up to 3 months usually; varies among patients

Other Indications & Uses

Off-label: Spasticity associated with cerebral palsy, chronic anal fissure; sialorrhea associated with ALS or Parkinson disease

Safety and efficacy not established



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            Adverse Effects

            Frequency Not Defined


            Dry mouth



            Injection site pain

            Flu-like symptoms





            Dry eye

            Accommodation disorder



            Black Box Warnings

            Distant spread of toxin effect

            • Effects of rimabotulinumtoxinB and all botulinum toxin products may spread from injection area to produce symptoms consistent with botulinum toxin effects
            • Symptoms have been reported hours to weeks after injection
            • Swallowing and breathing difficulties can be life threatening and death have been reported
            • Risk of symptoms may be greatest in children treated for spasticity but symptoms can also occur in adults, particularly in patients with an underlying condition which predispose them to these symptoms
            • In unapproved uses, including spasticity in children and adults, and in approved indications, cases of spread of effect have been reported at doses comparable to those used to treat cervical dystonia and at lower doses


            Hypersensitivity to any botulinum toxin product or to any of the components in the formulation

            Infection at proposed injection site


            Postmarketing safety data and other approved botulinum toxins suggest that botulinum toxin effects may, in some cases, be observed beyond the local injection site

            Potency units are not interchangeable with other preparations of botulinum toxin products and, therefore, units of biological activity of rimabotulinumtoxinB cannot be compared to or converted into units of any other botulinum toxin products assessed with any other specific assay method

            Serious hypersensitivity reaction (eg, angioedema, urticaria, rash) have been reported with botulinum toxin products have occurred

            Product contains albumin; based on effective donor screening and product manufacturing processes, it carries an extremely remote risk for transmission of viral diseases and variant Creutzfeldt-Jakob disease

            Peripheral motor neuropathic diseases (eg, ALS, motor neuropathy)

            Neuromuscular junctional disorders (eg, myasthenia gravis, Lambert-Eaton syndrome)

            Increased risk for severe dysphagia and respiratory compromise in pts with neuromuscular disorders

            Drug interaction overview

            • Coadministration with aminoglycosides or other agents interfering with neuromuscular transmission (eg, curare-like compounds) may potentiate effects of the toxin; use with caution
            • Use of anticholinergic drugs after administration of rimabotulinumtoxinB may potentiate systemic anticholinergic effects
            • Excessive weakness may be exaggerated by administration of a muscle relaxant before or after administration of rimabotulinumtoxinB
            • Other botulinum neurotoxin products
              • Effect of administering different botulinum toxin 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

            Pregnancy & Lactation


            There are no adequate data on the developmental risks associated with use in pregnant women

            No developmental toxicity was observed in pregnant rats administered rimabotulinumtoxinB by IM during gestation and lactation, at doses producing maternal toxicity


            There are no data on the presence of rimabotulinumtoxinB in human milk, the effects on the breastfed infant, or the effects on milk production

            Consider developmental and health benefits of breastfeeding along with the mother’s clinical need and any potential adverse effects on the breastfed infant or from the underlying maternal condition

            Pregnancy Categories

            A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

            B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

            C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

            D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

            X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

            NA: Information not available.



            Mechanism of Action

            Neurotoxin from Clostridium botulinum; blocks cholinergic transmission at the neuromuscular junction by inhibiting acetylcholine release from the peripheral cholinergic nerve endings


            Using currently available analytical technology, drug was not detectable in peripheral blood following IM or intraglandular injection at recommended doses




            Cervical dystonia: IM administration

            Chronic sialorrhea: Intraglandular administration

            Ready to use; no reconstitution required

            May dilute with 0.9% NaCl; once diluted, product must be used within 4 hr

            Discard any remaining solution in vial


            Refrigerate at 2-8ºC

            Protect from light

            Do not freeze; do not shake

            Do not use after expiration date stamped on vial





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            Tier Description
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