Which medications in the drug class Neuromuscular Blockers, Botulinum Toxins are used in the treatment of Hemifacial Spasm?

Updated: Sep 16, 2019
  • Author: Steven Gulevich, MD; Chief Editor: Nicholas Lorenzo, MD, MHA, CPE  more...
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Answer

Neuromuscular Blockers, Botulinum Toxins

Botulinum toxin type A is the drug of choice. [16, 17] It causes presynaptic paralysis of the myoneural junction and reduces abnormal contractions. Therapeutic effects may last 3-6 months.

Botulinum toxin type B is useful in reducing excessive, abnormal contractions associated with blepharospasm [18] ; binds to receptor sites on the motor nerve terminals and after uptake inhibits release of acetylcholine, blocking transmission of impulses in neuromuscular tissue; 7-14 d after administering initial dose, assess patients for a satisfactory response; increase doses 2-fold over previously administered dose for patients who experience incomplete paralysis of the target muscle.

OnabotulinumtoxinA (BOTOX)

OnabotulinumtoxinA (BOTOX) is useful in reducing excessive, abnormal contractions associated with blepharospasm. It binds to receptor sites on the motor nerve terminals and, after uptake, inhibits the release of acetylcholine, blocking transmission of impulses in neuromuscular tissue. At 7-14 days after administration of the initial dose, assess patients for a satisfactory response. Increase the dose 2-fold over the previously administered dose in patients who experience incomplete paralysis of the target muscle.

RimabotulinumtoxinB (Myobloc)

When botulinum toxin injection is indicated and type A toxin is ineffective, injection with type B toxin (rimabotulinumtoxinB [Myobloc]) should be considered.

AbobotulinumtoxinA (Dysport)

AbobotulinumtoxinA (Dysport) binds to receptor sites on the motor nerve terminals and, after uptake, inhibits release of acetylcholine, blocking transmission of impulses in neuromuscular tissue. At 7-14 days after administration of the initial dose, assess the patient for a satisfactory response. Increase the dose 2-fold over the previously administered dose in patients who experience incomplete paralysis of the target muscle.

IncobotulinumtoxinA (Xeomin)

Xeomin, a botulinum toxin type A product, may be used if Botox proves unsuccessful, or is unavailable.  It should produce satisfactory results, though systematic trials of Xeomin for HFS have not yet been reported.  Excess administration will produce undesirable weakness and facial asymmetry.  


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