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Myobloc Side Effects

Generic name: rimabotulinumtoxinB

Medically reviewed by Drugs.com. Last updated on Sep 2, 2024.

Note: This document provides detailed information about Myobloc Side Effects associated with rimabotulinumtoxinB. Some dosage forms listed on this page may not apply specifically to the brand name Myobloc.

Applies to rimabotulinumtoxinB: intramuscular solution.

Important warnings This medicine can cause some serious health issues

Intramuscular route (injectable)

Postmarketing reports indicate that the effects of rimabotulinumtoxinB 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.

Serious side effects of Myobloc

Along with its needed effects, rimabotulinumtoxinB (the active ingredient contained in Myobloc) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor or nurse immediately if any of the following side effects occur while taking rimabotulinumtoxinB:

More common side effects

  • difficulty with swallowing
  • infection
  • neck pain
  • uncontrolled twisting movements of the neck

Rare side effects

  • difficulty with breathing or speaking
  • muscle weakness

Incidence not known

  • cough
  • dizziness
  • fast heartbeat
  • hives, itching, or skin rash
  • large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
  • puffiness or swelling of the eyelids or around the eyes, face, lips or tongue
  • tightness in the chest
  • unusual tiredness or weakness

Other side effects of Myobloc

Some side effects of rimabotulinumtoxinB may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common side effects

  • acid or sour stomach
  • back pain
  • belching
  • bleeding, blistering, burning, coldness, discoloration of the skin, feeling of pressure, hives, infection, inflammation, itching, lumps, numbness, pain, rash, redness, scarring, soreness, stinging, swelling, tenderness, tingling, ulceration, or warmth at the injection site
  • cough
  • difficulty with moving
  • dizziness
  • dry mouth
  • flu-like syndrome
  • headache
  • heartburn or indigestion
  • lack or loss of strength or energy
  • muscle pain, stiffness, or weakness
  • nausea
  • pain, swelling, or redness in the joints
  • stomach discomfort, upset, or pain

Other side effects of Myobloc

Some side effects of rimabotulinumtoxinB may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Managing side effects (general information)

For healthcare professionals

Applies to rimabotulinumtoxinB: injectable solution, intramuscular solution.

General adverse events

The most commonly reported adverse events have included dry mouth, dysphagia, dyspepsia, and injection site pain.[Ref]

Gastrointestinal

Most case reports of dry mouth or dysphagia were reported as mild or moderate, however, these were the most frequent adverse events resulting in treatment discontinuation. An increased incidence of dysphagia occurred with an increased dose in the sternocleidomastoid muscle; an increasing incidence of dry mouth was associated with dose-related increases in doses injected into the splenius capitis, trapezius, and sternocleidomastoid muscles.

Gastrointestinal disorder, vomiting, glossitis, stomatitis, and tooth disorder were reported in greater than 2% of patients.[Ref]

Respiratory

Dyspnea, lung disorder, and pneumonia were reported in greater than 2% of patients.[Ref]

Cardiovascular

Chest pain, vasodilation, peripheral edema, and edema were reported in greater than 2% of patients.[Ref]

Local

Musculoskeletal

Arthritis and joint disorder were reported in greater than 2% of patients.[Ref]

Ocular

Hypersensitivity

Allergic reaction was reported in greater than 2% of patients.[Ref]

Nervous system

Migraine, hyperesthesia, somnolence, and taste perversion were reported in greater than 2% of patients.[Ref]

Dermatologic

Cyst, ecchymosis, and pruritus was reported in greater than 2% of patients.[Ref]

Immunologic

Viral infection and antibodies against botulinum toxin b were reported in greater than 2% of patients.[Ref]

Metabolic

Hypercholesterolemia was reported in greater than 2% of patients.[Ref]

Psychiatric

Anxiety and confusion were reported in greater than 2% of patients.[Ref]

Other

Chills, malaise, fever, vertigo, otitis media, tinnitus, tremor were reported in greater than 2% of patients.[Ref]

Genitourinary

Urinary tract infection, cystitis, and vaginal moniliasis were reported in greater than 2% of patients.[Ref]

Oncologic

Neoplasm was reported in greater than 2% of patients.[Ref]

References

1. "Product Information. Myobloc (rimabotulinumtoxinB)." Elan Pharmaceuticals

2. Cerner Multum, Inc. "UK Summary of Product Characteristics."

Frequently asked questions

Further information

Myobloc side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Note: Medication side effects may be underreported. If you are experiencing side effects that are not listed, submit a report to the FDA by following this guide.

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