Comprehensive medication guide to Myobloc including estimated pricing, availability information, side effects, and how to find it in stock at your local pharmacy.
Estimated Insurance Pricing
With commercial insurance and prior authorization, patient cost-share varies widely by plan; eligible commercially insured patients may pay $0 up to $4,000/year through the manufacturer copay program. Medicare does not cover Myobloc.
Estimated Cash Pricing
Approximately $1,777 average retail per 10,000-unit/2 mL vial; as low as $1,244 with SingleCare or GoodRx coupons at participating specialty pharmacies. No generic is available.
Medfinder Findability Score
65/100
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Myobloc is the brand name for rimabotulinumtoxinB, the only FDA-approved botulinum toxin type B product in the United States. It is an injectable prescription medication manufactured by Solstice Neurosciences (a subsidiary of Supernus Pharmaceuticals) and administered exclusively by trained healthcare providers.
Myobloc was first approved by the FDA in December 2000 for cervical dystonia — a painful neurological movement disorder causing involuntary neck muscle contractions and abnormal head positioning. In August 2019, its indications were expanded to include chronic sialorrhea (excessive drooling) in adults. It is particularly valuable for patients who have developed immunoresistance to botulinum toxin type A products such as Botox, Dysport, or Xeomin.
Myobloc is available in three single-dose vial sizes: 2,500 units/0.5 mL, 5,000 units/1 mL, and 10,000 units/2 mL — all at a concentration of 5,000 units/mL. Unlike type A botulinum toxins, it does not require reconstitution and comes ready-to-use. It must be stored refrigerated at 36°F–46°F and must not be frozen or shaken.
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Myobloc is an acetylcholine release inhibitor. When injected into a muscle or gland, the botulinum toxin type B complex binds to nerve endings at the neuromuscular junction. Its light chain then cleaves VAMP (vesicle-associated membrane protein, also known as synaptobrevin) — a critical component of the SNARE protein complex that nerve cells use to release acetylcholine.
With VAMP cleaved, the nerve ending cannot release acetylcholine into the neuromuscular junction. Without this chemical signal, the muscle cannot receive the instruction to contract — resulting in temporary relaxation of the overactive muscle. In salivary glands, the same mechanism reduces acetylcholine-driven secretion, decreasing saliva production.
Critically, Myobloc (type B) cleaves VAMP/synaptobrevin, while type A toxins (Botox, Dysport, Xeomin) cleave SNAP-25 — a different SNARE protein. This distinct molecular target is why Myobloc can work in patients who have developed neutralizing antibodies against type A products. The effects are temporary, lasting approximately 3–4 months, as nerve endings regenerate new axonal terminals over time.
2,500 units/0.5 mL — Injectable solution (single-dose vial)
5,000 units/1 mL — Injectable solution (single-dose vial)
10,000 units/2 mL — Injectable solution (single-dose vial)
Myobloc is not listed on the FDA Drug Shortages Database as of 2026, but it remains genuinely difficult to locate at most pharmacies. It is a brand-only specialty injectable with no generic equivalent, requires cold chain refrigeration (36°F–46°F), is not covered by Medicare, and serves a relatively small patient population. Most retail pharmacies do not carry it in standing inventory.
The most reliable sources are: specialty pharmacies (Accredo, CVS Specialty, Walgreens Specialty), hospital outpatient pharmacies affiliated with neurology programs, and the prescribing neurologist's office, which may stock it directly for in-office administration. Most patients need to start their search 4–6 weeks before their scheduled injection appointment.
Rather than calling specialty pharmacies yourself, medfinder calls pharmacies near you to check which ones have Myobloc in stock, then texts you the results — saving you hours of searching.
Myobloc is not a controlled substance, so any licensed prescriber can technically issue a prescription. However, because it requires specialized injection technique and is used for complex neurological conditions, it is almost always prescribed and administered by specialists with specific training in botulinum toxin therapies.
Typical Myobloc prescribers include:
Neurologists — primary prescribers for cervical dystonia
Movement disorder specialists — neurologists with subspecialty training in dystonia and related conditions; most experienced Myobloc prescribers
Otolaryngologists (ENT specialists) — may prescribe for chronic sialorrhea management
Physiatrists — physical medicine and rehabilitation physicians who treat movement disorders and spasticity
Nurse practitioners and physician assistants — in neurology practices, under physician supervision (state scope of practice laws vary)
Telehealth can be used for initial consultations, prescription authorization, and follow-up visits, but the Myobloc injection itself must be administered in person at a clinic or physician's office. Most patients see their prescribing neurologist every 3–4 months for their injection appointment.
No. Myobloc (rimabotulinumtoxinB) is not a DEA-scheduled controlled substance. It does not have the scheduling restrictions associated with narcotics, stimulants, benzodiazepines, or other controlled medications. You do not need a DEA-registered prescriber specifically for controlled substances, and there are no mandatory refill interval restrictions based on controlled substance scheduling.
However, Myobloc is a prescription-only medication requiring a valid prescription from a licensed healthcare provider. It must be administered by a trained healthcare professional in a clinical setting — it is not self-administered at home. Prior authorization from commercial insurance is required by virtually all payers. Medicare patients face an additional barrier as Myobloc is not currently covered by any Medicare plan.
FDA Boxed Warning: The botulinum toxin in Myobloc can spread beyond the injection site, causing botulism-like symptoms including generalized muscle weakness, vision problems, difficulty speaking or swallowing, urinary incontinence, and life-threatening breathing difficulties. These symptoms can occur hours to weeks after injection. Deaths have been reported. Seek emergency care immediately if these occur.
Common side effects (≥5% in clinical trials):
Dry mouth — up to 39% of patients
Dysphagia (difficulty swallowing) — up to 25% of patients
Injection site pain
Headache
Dyspepsia (indigestion)
Serious side effects requiring immediate medical attention:
Difficulty breathing or shortness of breath
Severe or worsening difficulty swallowing
Severe generalized muscle weakness
Allergic reactions (angioedema, urticaria, anaphylaxis)
Drooping eyelids, double or blurred vision
Hoarse voice or changes in speech
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Botox (onabotulinumtoxinA)
Type A botulinum toxin; FDA-approved for cervical dystonia and chronic sialorrhea; first-line for most patients; preferred by most insurers; covered by Medicare Part B
Dysport (abobotulinumtoxinA)
Type A botulinum toxin; FDA-approved for cervical dystonia in adults; broader diffusion profile; dosed at ~2.5-3x Botox units
Xeomin (incobotulinumtoxinA)
Type A 'naked' botulinum toxin without complexing proteins; FDA-approved for cervical dystonia; may have lower immunogenicity risk; 1:1 dosing with Botox
Daxxify (daxibotulinumtoxinA-lanm)
Newest type A botulinum toxin; FDA-approved for cervical dystonia; longest duration (6-9 months vs. 3-4 months); uses peptide stabilizer instead of albumin
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Other botulinum toxin products (Botox, Dysport, Xeomin, Daxxify)
majorConcurrent use or use within several months can produce additive, potentially excessive neuromuscular weakness
Aminoglycosides (gentamicin, amikacin, tobramycin)
moderateMay potentiate Myobloc's neuromuscular blocking effects; use with caution
Neuromuscular blocking agents (atracurium, vecuronium)
moderateCan potentiate neuromuscular weakness; usually relevant only in surgical settings
Anticholinergic drugs (oxybutynin, benztropine, diphenhydramine, atropine)
moderateMay potentiate systemic anticholinergic effects of Myobloc (dry mouth, constipation, urinary retention)
Muscle relaxants (baclofen, cyclobenzaprine, tizanidine)
moderateMay exaggerate Myobloc's muscle-weakening effects
Myobloc (rimabotulinumtoxinB) fills a critical therapeutic niche: it's the only FDA-approved botulinum toxin type B product in the US, specifically designed for patients with cervical dystonia or chronic sialorrhea who cannot benefit from type A toxins. Its distinct mechanism — cleaving VAMP/synaptobrevin rather than SNAP-25 — makes it effective even when type A products have stopped working.
The main challenges patients face are access (specialty injectable not stocked at most pharmacies), insurance (prior authorization with step therapy requirements, no Medicare coverage), and cost (roughly $1,777 per vial at retail). However, the manufacturer copay program ($0 for eligible commercially insured patients, up to $4,000/year) and prescription discount cards can significantly reduce the cost burden.
If you've been prescribed Myobloc and are having trouble finding it, medfinder can help. Provide your medication, dosage, and location — medfinder calls pharmacies near you to check who has Myobloc in stock and texts you the results. Start your search early — ideally 4–6 weeks before your scheduled injection appointment.
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