Myobloc Side Effects
Generic Name: botulinum toxin type b
Note: This page contains information about the side effects of botulinum toxin type b. Some of the dosage forms included on this document may not apply to the brand name Myobloc.
For the Consumer
Applies to botulinum toxin type b: intramuscular solution
In addition to its needed effects, some unwanted effects may be caused by botulinum toxin type b (the active ingredient contained in Myobloc). In the event that any of these side effects do occur, they may require medical attention.
If any of the following side effects occur while taking botulinum toxin type b, check with your doctor or nurse immediately:More common:
- Difficulty with swallowing
- neck pain
- uncontrolled twisting movements of the neck
- Difficulty with breathing or speaking
- muscle weakness
Some of the side effects that can occur with botulinum toxin type b may not need medical attention. As your body adjusts to the medicine during treatment these side effects may go away. Your health care professional may also be able to tell you about ways to reduce or prevent some of these side effects. If any of the following side effects continue, are bothersome or if you have any questions about them, check with your health care professional:More common:
- Acid or sour stomach
- back pain
- 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
- difficulty with moving
- dry mouth
- flu-like syndrome
- heartburn or indigestion
- lack or loss of strength or energy
- muscle pain, stiffness, or weakness
- pain, swelling, or redness in the joints
- stomach discomfort, upset, or pain
Some of the side effects that can occur with botulinum toxin type b may not need medical attention. As your body adjusts to the medicine during treatment these side effects may go away. Your health care professional may also be able to tell you about ways to reduce or prevent some of these side effects. If any of the following side effects continue, are bothersome or if you have any questions about them, check with your health care professional:
For Healthcare Professionals
Applies to botulinum toxin type b: injectable solution
Cardiovascular side effects have included headache (up to 16%) and chest pain.[Ref]
Dermatologic side effects including pruritus have been reported in 2% of patients or less.[Ref]
Gastrointestinal side effects have included dysphagia (up to 25%), dyspepsia (up to 10%), nausea (up to 10%), and to a lesser extent (2% or less) vomiting, glossitis, stomatitis, and tooth disorder.[Ref]
Dry mouth is the most commonly reported adverse effect (occurring in up to 34% of patients). Other general side effects have included torticollis (up to 8%) and, to a lesser extent (2% or less), fever, chills, hernia, malaise, abscess, cyst, and neoplasm.[Ref]
Genitourinary side effects reported in 2% of patients or less have included urinary tract infection, cystitis, and vaginal moniliasis.[Ref]
Immunologic side effects have included infection (up to 19%) and flu syndrome (up to 9%). Other immunologic side effects reported to a lesser extent (2% or less) have included otitis media and viral infection.[Ref]
Local side effects including injection site pain have been reported (up to 16%).[Ref]
Musculoskeletal side effects have included neck pain related to cervical dystonia (up to 17%), torticollis (up to 8%), arthralgia (up to 7%), back pain (up to 7%), myasthenia (up to 6%), and asthenia (up to 6%). Other musculoskeletal side effects reported in 2% of patients or less have included arthritis and joint disorder.[Ref]
Nervous system side effects reported in 2% of patients or less have included anxiety, tremor, hyperesthesia, somnolence, confusion, pain related to cervical dystonia/torticollis, vertigo, and vasodilation.[Ref]
Respiratory side effects have included increased cough (up to 7%), rhinitis (up to 6%), and, to a lesser extent (2% or less), dyspnea, lung disorder, and pneumonia.[Ref]
Ocular side effects including a case of bilateral ptosis have been reported.[Ref]
1. "Product Information. Myobloc (botulinum toxin type B)" Elan Pharmaceuticals, S. San Francisco, CA.
2. "Product Information. Botox (botulinum toxin type A)" Allergan Inc, Irvine, CA.
3. Racette BA, Lopate G, Good L, Sagitto S, Perlmutter JS "Ptosis as a remote effect of therapeutic botulinum toxin B injection." Neurology 59 (2002): 1445-7
Not all side effects for Myobloc may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.
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