RimabotulinumtoxinB Injection
RimabotulinumtoxinB injection (Myobloc) is a botulinum toxin used to treat cervical dystonia and chronic sialorrhea in adults.
🧬 Where this information comes from Click to expand
The clinical label records used on this page are FDA-filed Structured Product Labeling (SPL) retrieved through openFDA. We identified 1 clinical label set within the page’s selected clinical scope after exact ingredient or ingredient-combination matching and applicable route/form matching. Forms, routes, brands, labelers, strengths, and NDC product-record counts are built separately from matching FDA National Drug Code Directory records. The linked DailyMed document is a representative official source for verification, not the page’s only clinical source. View the linked label on DailyMed →
⚠️ FDA Boxed Warning — the FDA’s strongest safety alert ▾
Important Safety Warning: The effects of Myobloc can spread beyond the injection site to other parts of the body. This spread can cause symptoms such as general muscle weakness, difficulty swallowing, difficulty speaking, drooping eyelids, double or blurred vision, loss of bladder control, and serious breathing problems. These symptoms have appeared anywhere from a few hours to several weeks after an injection. Swallowing and breathing difficulties can be life-threatening and deaths have been reported. The risk appears highest in children treated for spasticity (a use that is NOT FDA-approved), but adults — especially those with underlying health conditions — can be affected too. Seek immediate medical attention if you or someone you care for develops any of these symptoms after a Myobloc injection.
📖 RimabotulinumtoxinB Injection: Patient Information Guide
A plain-language walkthrough of RimabotulinumtoxinB Injection — what it treats, how it works, how it’s taken, side effects, warnings and interactions. Tap any section to expand it.
🎯What it's used for▾
RimabotulinumtoxinB injection is a botulinum toxin type B product. All approved uses below are for the brand Myobloc, given by intramuscular injection to adults.
- Cervical dystonia: Myobloc is injected into the affected neck muscles to reduce the severity of involuntary head and neck position changes and the neck pain that comes with them.
- Chronic sialorrhea: Myobloc is injected into the parotid and submandibular salivary glands to reduce excessive, persistent drooling in adults.
⚙️How it works▾
Myobloc works by preventing nerve endings from releasing acetylcholine — the chemical signal that tells muscles to contract and glands to produce secretions. Once injected, the toxin binds to nerve terminals, enters them, and cuts a key protein (VAMP, also called synaptobrevin) that is essential for releasing acetylcholine. Without that signal, overactive muscles relax and overactive salivary glands slow down. The effect is temporary: the body gradually forms new nerve endings over several months, restoring normal signaling.
💊How it's taken▾
Myobloc is given as an injection by a trained healthcare provider — it is not self-administered at home. For cervical dystonia, it is injected into the affected neck muscles; dosing depends on whether you have previously tolerated botulinum toxin injections. For chronic sialorrhea, it is injected into the parotid and submandibular salivary glands, with repeat treatments generally no more often than every 12 weeks.
- The duration of effect for cervical dystonia is typically 12 to 16 weeks in responding patients.
- The duration of effect for chronic sialorrhea is typically up to 3 months, though this can vary.
- Your doctor will adjust the schedule and dose based on how well you respond and how well you tolerate the treatment.
🤒Side effects — in detail▾
The most commonly reported side effects with Myobloc include:
- Dry mouth — very common, especially at higher doses; can be severe in some patients
- Difficulty swallowing (dysphagia) — can range from mild to severe
- Injection site pain
- Headache
- Indigestion (dyspepsia)
- Flu-like symptoms
- Dizziness
- Back pain or general aching
- Dental cavities (seen in chronic sialorrhea studies)
Dry mouth and difficulty swallowing are the side effects most often leading people to stop treatment. Get immediate medical help if you develop any trouble breathing, severe swallowing difficulty, or widespread muscle weakness after an injection — these are serious warning signs that need urgent care.
⚠️Warnings & precautions▾
- Toxin spread (most critical risk): Myobloc's effects can travel beyond the injection site and cause body-wide muscle weakness, difficulty breathing, difficulty swallowing, drooping eyelids, double vision, slurred speech, and bladder control problems. This can happen hours to weeks after the shot and has caused deaths. Seek emergency care immediately if these symptoms develop.
- Neuromuscular conditions: People with diseases like myasthenia gravis, Lambert-Eaton syndrome, or ALS are at especially high risk for severe breathing and swallowing complications — even from typical doses. Close monitoring is essential.
- Dosing units are not interchangeable: Myobloc's units are unique and cannot be compared to or converted into units for any other botulinum toxin product. Using another product's dosing as a guide could cause serious harm.
- Serious allergic reactions: Reactions including severe swelling (angioedema), hives, and anaphylaxis have been reported. Seek immediate care if these occur.
- Human albumin content: Myobloc contains a blood-derived protein (human albumin), carrying an extremely remote risk of viral disease transmission — no cases have ever been reported.
🔀What it interacts with▾
Tell your doctor about all medications you take before receiving Myobloc — certain drugs can make its muscle-weakening effects stronger or cause other complications:
- Aminoglycoside antibiotics (e.g., gentamicin, tobramycin): can amplify Myobloc's toxin effects, increasing risk of weakness and breathing problems
- Other neuromuscular blocking agents (e.g., curare-like compounds): also intensify the toxin's effects — use only with great caution
- Anticholinergic drugs (used for bladder conditions, motion sickness, Parkinson's, and others): can worsen systemic side effects like dry mouth when used after Myobloc
- Muscle relaxants: can cause excessive muscle weakness when taken before or after Myobloc
- Other botulinum toxin products: receiving another botulinum toxin within several months can lead to dangerous, additive muscle paralysis
This is not a complete list of interactions. Always talk with your doctor or pharmacist before starting, stopping, or changing any medication.
📋Before taking it▾
- Do not use Myobloc if you have ever had a serious allergic reaction to any botulinum toxin or to human albumin or sucrose
- Do not receive Myobloc if there is an active infection at or near the planned injection site
- Tell your doctor if you have a neuromuscular disease (such as myasthenia gravis, Lambert-Eaton syndrome, or ALS) — you face a higher risk of severe, dangerous side effects
- Tell your doctor if you already have trouble swallowing or breathing before treatment begins
- Myobloc has not been shown to be safe or effective in children — it is approved for adults only
- If you are pregnant or trying to become pregnant, there are not enough data to confirm safety — discuss the benefit-versus-risk with your doctor
- If you are breastfeeding, there is no information on whether Myobloc passes into breast milk — talk with your doctor before receiving treatment
- Adults 75 and older have limited data; your doctor should monitor you carefully for any increased sensitivity
🚑If you take too much▾
Too much Myobloc can cause excessive muscle weakness or paralysis throughout the body, which may include the muscles needed for breathing. If an overdose is suspected, the patient should be medically monitored for signs of muscle weakness or paralysis — symptoms may not appear immediately after the injection. In serious cases, breathing support may be required, and an antitoxin is available through the Centers for Disease Control and Prevention (CDC); contact your local or state health department, or call the CDC directly at 770-488-7100.
📡Pharmacodynamics — effects in the body▾
In people who respond to Myobloc treatment, the targeted muscles or salivary glands gradually return toward their previous activity level as the toxin's effect wears off. For cervical dystonia, increased muscle tone typically begins returning within 3 to 4 months after injection. Similarly, saliva production starts to increase again around the same timeframe in sialorrhea patients. This is why repeat injections are needed to maintain the benefit.
🔬Pharmacokinetics — how your body processes it▾
Using current laboratory technology, Myobloc cannot be detected in the bloodstream after intramuscular or salivary gland injection at recommended doses. This means the drug acts locally at the injection site rather than circulating at measurable levels through the body — though the boxed warning makes clear that some spread beyond the local area can still occur in some patients.
📦How to store it▾
Store under refrigeration at 2°C to 8°C (36°F- 46°F) in the original carton to protect from light. DO NOT FREEZE.
📄 Written from RimabotulinumtoxinB Injection’s FDA-approved label information, summarized in plain language with AI, and reviewed by our pharmacy team before publication. Every point is grounded in that labeling — nothing is invented. How we use AI →
🩺 Pharmacist Counseling Corner
Quick, plain-English answers to the questions patients ask most about RimabotulinumtoxinB Injection — the kind of thing our pharmacy team would talk through with you at the counter.
What exactly is Myobloc used for? ▾
How long does Myobloc last, and how often will I need injections? ▾
What side effects should I expect, and which ones should make me call for help? ▾
Is it true Myobloc can affect muscles far from the injection site? ▾
Are there medications I should avoid while getting Myobloc injections? ▾
Can I receive Myobloc if I'm pregnant or trying to conceive? ▾
Is RimabotulinumtoxinB Injection available over the counter? ▾
When was RimabotulinumtoxinB Injection first available? ▾
💬 Answers drafted from RimabotulinumtoxinB Injection’s FDA-approved label information, summarized in plain language with AI, and reviewed by our pharmacy team before publication. Grounded in that labeling — nothing is made up. How we use AI →
🧰 Keep exploring
💊 How RimabotulinumtoxinB Injection comes
RimabotulinumtoxinB Injection is available in 1 form. Different forms and brands can have different approved uses, doses, schedules, and directions. Follow the instructions for your exact product, and do not switch forms without guidance from your prescriber or pharmacist.
Injection
How this form is used
- Myobloc is used to treat cervical dystonia in adults — reducing abnormal head position and neck pain
- Myobloc is used to treat chronic sialorrhea (excessive drooling) in adults by reducing saliva production from the parotid and submandibular glands
- Myobloc is given by intramuscular injection into affected neck muscles (for cervical dystonia) or into salivary glands (for chronic sialorrhea) by a trained healthcare provider
- Myobloc comes ready to use with no mixing required; it may be diluted with saline if needed, but must be used within 4 hours of dilution
- Myobloc injections for chronic sialorrhea should generally be given no more frequently than every 12 weeks
- Myobloc is for single-patient, single-session use only — any unused solution remaining in the vial must be discarded
📊 RimabotulinumtoxinB Injection across the U.S. market
How RimabotulinumtoxinB Injection appears in the FDA’s National Drug Code Directory — including its dosage forms, strengths, brand names, manufacturers, and FDA-listed product records. These are directory records, not sales or prescription volume.
📈 How widely RimabotulinumtoxinB Injection is used
A general measure of how commonly RimabotulinumtoxinB Injection is prescribed, based on Medicaid — one of the largest public drug programs. The figure below is prescriptions filled in Q1–Q4 2025, summed across every form and brand of the drug.
Think of this as a proxy for how widely RimabotulinumtoxinB Injection is used, drawn from freely available public data. Medicaid is just one program — these numbers don’t include Medicare, other government coverage, or commercial and cash-pay prescriptions, so real-world use is higher than what’s shown here.
How commonly is RimabotulinumtoxinB Injection prescribed? Of the 1,596 medications we measure, RimabotulinumtoxinB Injection ranks #1,461 by Medicaid prescriptions — more than 8% of them.
Utilization by RimabotulinumtoxinB Injection product
Pick a product to see its own Medicaid numbers. Each chip is one clinical product — a specific strength & dosage form as defined by RxNorm — with brand-name and generic versions combined.
Other RimabotulinumtoxinB Injection products — combination packs and listings not yet matched to a specific clinical product (kept visible so every prescription is accounted for)
Summed across the 3 of 3 listed NDC products with Medicaid activity.
Shares are of the Medicaid prescriptions shown here. Product grouping follows RxNorm (the National Library of Medicine’s drug terminology), so “one product” means one strength & dosage form regardless of manufacturer. Dollar figures are gross Medicaid reimbursement before mandatory rebates — rebates (often large, especially for brand-name drugs) are confidential, so actual net cost to Medicaid is lower than shown.
Source: Medicaid State Drug Utilization Data (CMS), aggregated by generic ingredient — summed across every NDC (all brands, strengths, salt forms and dosage forms) of RimabotulinumtoxinB Injection, and across all states and both fee-for-service and managed-care claims. A general popularity signal; it excludes Medicare, commercial insurance and cash prescriptions, so it is not total U.S. use. Based on the 3 of 3 listed RimabotulinumtoxinB Injection NDCs with Medicaid activity.
🔍 Compare RimabotulinumtoxinB Injection products
A representative set of FDA-listed product records for RimabotulinumtoxinB Injection — across manufacturers, strengths, and dosage forms, grouped by form with each product’s manufacturer and how the FDA approved it. The same medicine may be made and packaged by different companies, so a single drug can have many directory entries. (It’s also why a refill can look different — a new shape, color, or box — even though it contains the same medication.)
| Strength | Route | Manufacturer / Labeler | Category ⓘ | Details |
|---|---|---|---|---|
| 💊Injection | ||||
| 2500 [USP'U]/0.5 mL | Intramuscular | Solstice Neurosciences, LLC × 3 listings | BLA | View NDC → |
| 5000 [USP'U]/mL | Intramuscular | Solstice Neurosciences, LLC × 3 listings | BLA | View NDC → |
| 10000 [USP'U]/2 mL | Intramuscular | Solstice Neurosciences, LLC × 3 listings | BLA | View NDC → |
Showing 9 of 9 products — FDA National Drug Code Directory. See every product, package size and price: browse all 9 RimabotulinumtoxinB Injection NDCs →
📈 What people report — real-world data (FDA FAERS)
After a medicine reaches the market, patients, doctors and drugmakers can send the FDA reports of problems they think may be linked to it. Here’s what’s been reported for RimabotulinumtoxinB Injection — a signal of what to watch for, not proof the drug caused it.
Source: openFDA, from the FDA Adverse Event Reporting System (FAERS). These are voluntary reports — they don’t prove the drug caused the effect, and counts reflect how often something was reported, not how often it actually happens. Reports also often name the very problem the medicine is taken for — a common reason to file one is that the drug didn’t help — so for a pain reliever you may see “pain” high on the list; that points to why the report was filed, not to the drug causing the symptom. This counts every report that lists RimabotulinumtoxinB Injection in any role, so the total runs higher than the FDA’s official dashboard, which counts only cases where the drug is the suspect. For the authoritative figures, see the FDA FAERS Public Dashboard. Always talk to your pharmacist or doctor.
🏛️ The road to your pharmacy
How RimabotulinumtoxinB Injection went from FDA review to the pharmacy shelf — the key milestones in its regulatory journey.
Source: Drugs@FDA.
🚨 Recall history
A recall is when a specific batch of a medicine is pulled from the market — usually a manufacturing issue, not a problem with the drug itself. Class I is most serious, Class III least.
Source: openFDA drug enforcement (recall) reports.
📦 Supply & shortage status
Whether RimabotulinumtoxinB Injection is in short supply in the U.S. right now, plus any shortage history the FDA has on record. A shortage usually reflects a manufacturing or demand issue — not a safety problem with the drug.
Source: openFDA, from the FDA Drug Shortages database.
🏷️ Sold under these brand names
🏭 Manufacturers & labelers
RxNorm drug class
RimabotulinumtoxinB Injection belongs to the Acetylcholine Release Inhibitor class.
Classified by RxNorm RxClass — the U.S. National Library of Medicine's standardized drug-classification service (Established Pharmacologic Class from the FDA, the ATC drug family from the WHO, and mechanism of action). Reference only, not medical advice.
🔬 Where this comes from
Core label, product, RxNorm, safety, and utilization data on this page come from the sources identified below. AI-written, editorial, and licensed sections are labeled separately.
How we combine label and product data
HelloPharmacist combines public FDA and NLM records; we don’t author the underlying clinical facts. We identified 1 FDA-filed SPL label set within the page’s selected clinical scope after exact ingredient or ingredient-combination matching and applicable route/form matching. The representative label is the starting point for the displayed reference monograph; the 12 largest stored in-scope SPL records, which may include that representative, are compared section by section, and the longest available version of each section is retained. Forms, routes, brands, labelers, product-listed strengths, and product-record counts are aggregated separately from ingredient-matched FDA NDC Directory records; package records listed above are associated with the linked SPL; and the normalized concept hierarchy comes from NLM RxNorm.
Where a section is identified as AI-written, its plain-language text is generated from bounded label evidence. New draft drug pages remain in the admin review queue before first publication. Solstice Neurosciences, LLC is the representative DailyMed label linked for verification and dates; it is not the sole source used for the page.
This is general education, not medical advice — always consult your doctor or pharmacist about your medications and any medical condition. For the exact wording of the linked representative label, view that label on DailyMed; some displayed composite sections may come from other in-scope SPL labels. Learn how we use AI and our data sources & update cadence.