Myobloc

Myobloc is a prescription medication that is injected into muscles and used to treat the abnormal head position and neck pain that happens with cervical dystonia (CD). Myobloc is also injected into glands that make saliva and is used to treat long-lasting (chronic) drooling (sialorrhea).

Myobloc belongs to a group of drugs called acetylcholine release inhibitors. It works by disabling a protein that would typically trigger the release of excessive acetylcholine. When injected into affected muscles in CD patients, it blocks the release of acetylcholine, allowing the muscles to relax. For sialorrhea, it works by reducing excessive acetylcholine near the salivary glands, which causes the glands to produce less saliva.

This medication comes as an injection that your doctor will give you. Myobloc is injected into your affected muscles or glands.

Common side effects include dry mouth, trouble swallowing, pain at the injection site, and headache. Myobloc may cause loss of strength or general muscle weakness or vision problems within hours to weeks of receiving Myobloc. If this happens, do not drive a car, operate machinery or do other dangerous activities.

Myobloc is a prescription medicine used in adults that is injected into:

• muscles and used to treat the abnormal head position and neck pain that happens with cervical dystonia (CD).
• glands that make saliva and is used to treat long-lasting (chronic) drooling (sialorrhea).

It is not known whether Myobloc is safe or effective in children.

This medication may be prescribed for other uses. Ask your doctor or pharmacist for more information.

Serious side effects may occur. See "Myobloc Precautions" section.

Common side effects in people with cervical dystonia include:

• dry mouth
• trouble swallowing
• pain or discomfort at injection site
• headache

The most common side effects of Myobloc in people with sialorrhea include dry mouth and trouble swallowing.

These are not all the possible side effects of Myobloc. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088. You may also report side effects to www.fda.gov/medwatch.

Tell your doctor about all the medicines you take, including prescription and over-the-counter medicines, vitamins and herbal supplements. Talk to your doctor before you take any new medicine after you receive Myobloc.

Using Myobloc with certain other medicines may cause serious side effects. Do not start any new medicines until you have told your doctor that you have received Myobloc in the past. Especially tell your doctor if you:

• have received any other botulinum toxin product in the last 4 months.
• have received injections of botulinum toxin such as Botox, Botox Cosmetic (onabotulinumtoxin A), Dysport (abobotulinumtoxin A), or Xeomin (incobotulinumtoxin A) in the past. Be sure your doctor knows exactly which product you received.
• have recently received an antibiotic by injection.
• take muscle relaxants.
• take an allergy or cold medicine.
• take a sleep medicine.

Ask your doctor if you are not sure if your medicine is one that is listed above.

Know the medicines you take. Keep a list of your medicines with you to show your doctor and pharmacist each time you get a new medicine.

Myobloc may cause serious side effects that can be life threatening. Call your doctor or get medical help right away if you have any of these problems after treatment with Myobloc:

• Problems swallowing, speaking, or breathing. These problems can happen hours to weeks after an injection of Myobloc if the muscles that you use to breathe and swallow become weak after the injection. Death can happen as a complication if you have severe problems with swallowing or breathing after treatment with Myobloc. 
  • People with certain breathing problems may need to use muscles in their neck to help them breathe. These people may be at greater risk for serious breathing problems with Myobloc.
  • Swallowing problems may last for several months. People who cannot swallow well may need a feeding tube to receive food and water. If swallowing problems are severe, food or liquids may go into your lungs. People who already have swallowing or breathing problems before receiving Myobloc have the highest risk of getting these problems.
• Spread of toxin effects. In some cases, the effect of botulinum toxin may affect areas of the body away from the injection site and cause symptoms of a serious condition called botulism. The symptoms of botulism include:
  • loss of strength and muscle weakness all over the body
  • double vision
  • blurred vision and drooping eyelids
  • hoarseness or change or loss of voice (dysphonia)
  • trouble saying words clearly (dysarthria)
  • loss of bladder control
  • trouble breathing
  • trouble swallowing (dysphagia)

These symptoms can happen hours to weeks after you receive an injection of Myobloc.

These problems could make it unsafe for you to drive a car or do other dangerous activities.

• Allergic reactions. Symptoms of an allergic reaction to Myobloc may include:
  • itching
  • rash
  • redness
  • swelling
  • wheezing
  • trouble breathing
  • dizziness or feeling faint.

Tell your doctor or get medical help right away if you get wheezing, or trouble breathing, or if you get dizzy or faint.

Do not receive Myobloc if you:

• are allergic to Myobloc or any of the ingredients in Myobloc. 
• had an allergic reaction to any other botulinum toxin product such as Botox, Botox Cosmetic (onabotulinumtoxin A), Dysport (abobotulinumtoxin A), or Xeomin (incobotulinumtoxin A).
• have a skin infection at the planned injection site.

Myobloc may cause loss of strength or general muscle weakness or vision problems within hours to weeks of receiving Myobloc. If this happens, do not drive a car, operate machinery or do other dangerous activities.

Medications can interact with certain foods. In some cases, this may be harmful and your doctor may advise you to avoid certain foods. In the case of Myobloc, there are no specific foods that you must exclude from your diet when receiving this medication.

Before receiving Myobloc, tell your doctor about all your medical conditions, including if you have:

• a disease that affects your muscles and nerves (such as amyotrophic lateral sclerosis [ALS or Lou Gehrig’s disease], myasthenia gravis or Lambert- Eaton syndrome).
• had any side effect from any botulinum toxin product in the past.
• a breathing problem, such as asthma or emphysema.
• a history of swallowing problems or inhaling food or fluid into your lungs (aspiration).
• bleeding problems.
• drooping eyelids.
• plans to have surgery.
• had surgery on your face.

Tell your doctor if you:

• are pregnant or plan to become pregnant. It is not known if Myobloc can harm your unborn baby.
• are breastfeeding or plan to breastfeed. It is not known if Myobloc passes into breast milk.

Tell your doctor about all the medicines you take, including prescription and over-the-counter medicines, vitamins and herbal supplements.

Tell your doctor if you are pregnant or plan to become pregnant.

There are no well-done studies that have been done in humans with Myobloc. In animal studies, pregnant animals were given this medication and the babies did not show any medical issues related to this medication. This medication may be used if the potential benefits to the mother outweigh the potential risks to the unborn child.

Tell your doctor if you are breastfeeding or plan to breastfeed.

It is not known if Myobloc crosses into human milk. Because many medications can cross into human milk and because the possibility for serious adverse reactions in nursing infants with use of this medication, a choice should be made whether to stop nursing or stop the use of this medication. Your doctor and you will decide if the benefits outweigh the risk of using Myobloc.

• Myobloc is a shot (injection) that your doctor will give you.
• Myobloc is injected into your affected muscles or glands.
• Your doctor may give you another dose of Myobloc after 12 weeks or longer, if it is needed.
• Your doctor may change your dose of Myobloc, until you and your doctor find the best dose for you.

The Recommended Myobloc Dose:

For 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.

For 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.

Myobloc is usually administered by a healthcare provider in a medical setting making it unlikely for an overdose to occur. However, if overdose is suspected, seek emergency medical attention.

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. The risk of symptoms is probably greatest in children treated for spasticity but symptoms can also occur in adults treated for spasticity and other conditions, particularly in those patients who have underlying conditions that would predispose them to these symptoms. In unapproved uses, including spasticity in children and adults, and in approved indications, cases of spread of effect have occurred at doses comparable to those used to treat cervical dystonia and at lower doses.