The use of botulinum toxin type‐B in the treatment of patients who have become unresponsive to botulinum toxin type‐A – initial experiences

Abstract

The increasing use of botulinum toxin type-A, especially for focal dystonia and spasticity has highlighted the issue of secondary non-responsiveness. Within the last few years botulinum toxin type-B (Myobloc/Neurobloc) has become commercially available as an alternative to type-A. This paper discusses our initial experience of botulinum toxin type-B in a total of 63 individuals who attended our botulinum clinic. Thirty-six patients had cervical dystonia and a secondary non-response to type-A toxin. Thirteen of these patients (36%) had a reasonable clinical response to Neurobloc and continue to have injections. The other 23 patients either had no response, or a poor response, or had unacceptable side effects and ceased treatment. A small number of people with blepharospasm, hemifacial spasm and foot dystonia also had a disappointing response to injection. Twenty patients with spasticity were also type-A resistant. Seven of these show some continuing response to type-B, without unacceptable side effects. These findings demonstrate that botulinum toxin type-B has a place in the management of patients who have become non-responsive to type-A, but overall the responses to type-B toxin were disappointing.

Clinical differences between botulinum neurotoxin type A and B

“…Rima/B injection is associated with significantly more pain in the injection site than Ona/A, Abo/A, saline (Colosimo et al, 2003;Barnes et al, 2005;Kranz et al, 2006), perhaps related to the low pH (5.6), as normalization to 7.5 the pH with sodium bicarbonate reduced pain in 3 individuals (Lowe and Lowe, 2014) although cannot be recommended because of the potential to alter the effect of the toxin. Xerostomia (dry mouth) is the most frequently reported side effect of BoNT/B in all the studies at higher frequency and severity than BoNT/A Dressler and Benecke, 2003), even with very low doses (Blitzer, 2005).…”

Surgical approach to limiting skin contracture following protractor myectomy for essential blepharospasm

“…[4][5][6][7][8][9][10][11][12][13] Although many patients experience rapid symptomatic relief, the effects of botulinum toxin are temporary, and many patients develop resistance to its effects with repeated injections. Thus, there are patients whose symptoms are poorly controlled with botulinum toxin injections alone.…”

“…[1][2][3] The first-line treatment for this condition is serial botulinum A toxin injections, which are effective for the rapid but temporary treatment of BEB. [4][5][6][7][8][9][10][11][12][13] In patients who fail to respond to this treatment, protractor myectomy, which has been performed routinely for decades, remains a highly effective treatment, with few complications. [14][15][16][17][18][19][20][21][22][23] Nevertheless, postoperative complications can arise, including hemorrhage, hematoma, lid edema, lagophthalmos, skin necrosis, and skin contracture.…”

Botulinum toxin in the management of blepharospasm: current evidence and recent developments

“…The experience and level of evidence on BoNT-B is much smaller than that of BoNT-A preparations, likely because the former produces more painful injections. A few small, single-center, open-label, retrospective reports have provided some insight into the use of rimabotulinumtoxinB in blepharospasm, most reporting benefit and tolerable side effects [Colosimo et al 2003;Cardoso, 2003;Barnes et al 2005]. In a single-center, single-injector report of 16 patients, average total dose was 3633 units per session [Dutton et al 2006].…”