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Generic Name: rimabotulinumtoxinB (Myobloc) (RYE ma BOT ue LYE num TOX in B)
Brand Name: Myobloc

Medically reviewed by on Sep 14, 2018 – Written by Cerner Multum

What is rimabotulinumtoxinB (Myobloc)?

RimabotulinumtoxinB (Myobloc), also called botulinum toxin type B, is made from the bacteria that causes botulism. Botulinum toxin blocks nerve activity in the muscles, causing a temporary reduction in muscle activity.

Myobloc is used to treat cervical dystonia (severe spasms in the neck muscles).

Myobloc may also be used for purposes not listed in this medication guide.

Important Information

You should not receive rimabotulinumtoxinB if you are allergic to botulinum toxin, or if you have a skin infection in the area where the medicine will be injected.

The botulinum toxin contained in this medication can spread to other body areas beyond where it was injected. This can cause serious life-threatening side effects.

Call your doctor at once if you have a hoarse voice, drooping eyelids, vision problems, severe muscle weakness, loss of bladder control, or trouble breathing, talking, or swallowing. Some of these effects can occur up to several weeks after a botulinum toxin injection.

Before taking this medicine

You should not receive this medicine if you are allergic to botulinum toxin, or if you have a skin infection in the area where the medicine will be injected. Tell your doctor if you have ever had a side effect after receiving botulinum toxin in the past.

To make sure Myobloc is safe for you, tell your doctor if you have:

  • amyotrophic lateral sclerosis (ALS, or "Lou Gehrig's disease");

  • myasthenia gravis;

  • Lambert-Eaton syndrome;

  • a breathing problem such as asthma or emphysema;

  • problems with swallowing;

  • bleeding problems;

  • if you are planning to have surgery; or

  • if you have ever received other botulinum toxin injections such as Botox or Dysport (especially in the last 4 months).

Myobloc is made from human plasma (part of the blood) which may contain viruses and other infectious agents. Donated plasma is tested and treated to reduce the risk of it containing infectious agents, but there is still a small possibility it could transmit disease. Talk with your doctor about the risks and benefits of using this medication.

It is not known whether this medicine will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

It is not known whether Myobloc passes into breast milk or if it could harm a nursing baby. Tell your doctor if you are breast-feeding a baby.

How is Myobloc given?

rimabotulinumtoxinB is injected into a muscle. A doctor, nurse, or other healthcare provider will give you this injection. Myobloc injections should be spaced at least 3 months apart.

Your injection may be given into more than one area at a time, depending on the condition being treated.

The effects of a Myobloc injection are temporary. Your symptoms may return completely within 3 months after an injection. After repeat injections, it may take less and less time before your symptoms return, especially if your body develops antibodies to the botulinum toxin.

Do not seek botulinum toxin injections from more than one medical professional at a time. If you switch healthcare providers, be sure to tell your new provider how long it has been since your last botulinum toxin injection.

Using this medicine more often than prescribed will not make it more effective and may result in serious side effects.

What happens if I miss a dose?

Since botulinum toxin has a temporary effect and is given at widely spaced intervals, missing a dose is not likely to be harmful.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Overdose symptoms may not appear right away, but can include muscle weakness, trouble swallowing, and weak or shallow breathing.

What should I avoid after receiving Myobloc?

Myobloc may impair your vision or depth perception. Be careful if you drive or do anything that requires you to be able to see clearly.

Myobloc side effects

Get emergency medical help if you have signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

The botulinum toxin contained in rimabotulinumtoxinB can spread to other body areas beyond where it was injected. This has caused serious life-threatening side effects in some people receiving botulinum toxin injections, even for cosmetic purposes.

Call your doctor at once if you have any of these side effects, some of which can occur up to several weeks after an injection:

  • trouble breathing, talking, or swallowing;

  • hoarse voice, drooping eyelids;

  • unusual or severe muscle weakness (especially in a body area that was not injected with the medication);

  • loss of bladder control;

  • problems with vision; or

  • chest pain.

Common side effects may include:

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

RimabotulinumtoxinB dosing information

Usual Adult Dose for Cervical Dystonia:

For patients who have demonstrated tolerability to botulinum toxin:
Initial dose: 2500 to 5000 Units IM divided among affected muscles

For patients who have not demonstrated tolerability to botulinum toxin:
-Lower initial doses are recommended

Subsequent dosing should be optimized according to patient's response
-Duration of effect: 12 to 16 weeks (at doses of 5000 to 10,000 Units)

-This drug should be administered by physicians familiar and experienced in the assessment and management of patients with cervical dystonia.

Use: To reduce the severity of abnormal head position and neck pain associated with cervical dystonia.

What other drugs will affect botulinum toxin type B?

Other drugs such as cold or allergy medicines, muscle relaxers, sleeping pills, bronchodilators, bladder or urinary medications, and irritable bowel medications can increase some of the side effects of Myobloc. Tell your doctor if you regularly use any of these medicines.

Tell your doctor about all your current medicines and any you start or stop using, especially:

This list is not complete. Other drugs may interact with Myobloc, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this medication guide.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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