Botulinum toxin A and B: a comparative dosing study for spasmodic dysphonia.

Abstract

OBJECTIVE:

The purpose of this study was to find the conversion factor, safety, and efficacy of type A to type B toxin for laryngeal muscles.

METHODS:

Thirty-two patients with adductor spasmodic dysphonia with stable doses of A toxin to manage their symptom were given type B toxin starting at a conversion of 1 U of BTX-A to 50 U of BTX-B. The patients were followed for 1 year, and doses adjusted according to response.

RESULTS:

The conversion factor was found to be 52.3 U:1 U. The onset of action of type B was more rapid (2.09 days vs 3.2 days [P = 0.028]), with a shorter duration of benefit (10.8 weeks vs 17 weeks [P = 0.002). The safety profile for A and B toxin appeared the same, with 3 patients receiving Myobloc reporting dry mouth.

CONCLUSION:

This study shows that a conversion factor of 52.3:1 Myobloc (BTX-B) to Botox (BTX-A) and that Myobloc is an effective alternative to Botox (BTX-A) for patients with spasmodic dysphonia.

• Authors: Andrew Blitzer
• Journal: Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery (Otolaryngol Head Neck Surg) Vol. 133 Issue 6 Pg. 836-8 (Dec 2005) ISSN: 0194-5998 [Print] England
• PMID: 16360499 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Neuromuscular Agents
• rimabotulinumtoxinB
• Metalloendopeptidases
• Botulinum Toxins
• Botulinum Toxins, Type A

Topics

• Botulinum Toxins (administration & dosage, therapeutic use)
• Botulinum Toxins, Type A (administration & dosage, therapeutic use)
• Dose-Response Relationship, Drug
• Female
• Follow-Up Studies
• Humans
• Laryngeal Muscles (drug effects, physiopathology)
• Male
• Metalloendopeptidases (administration & dosage, therapeutic use)
• Muscle Contraction (drug effects)
• Neuromuscular Agents (administration & dosage, therapeutic use)
• Treatment Outcome
• Voice Disorders (drug therapy, physiopathology)