Houser M K, Sheean G L, Lees A J
The National Hospital for Neurology and Neurosurgery, London, UK.
J Neurol Neurosurg Psychiatry. 1998 May;64(5):577-80. doi: 10.1136/jnnp.64.5.577.
A previous study of botulinum toxin type F (BTX-F) treatment for torticollis had shown a dose of 520 MU to be effective, but for a much shorter duration than is usual with botulinum toxin type A (BTX-A). The objective was to assess the effect of a higher dose of BTX-F.
Four of the previously treated patients, plus an additional patient, were treated with a higher dose of 780 MU BTX-F. All were secondary nonresponders to BTX-A due to neutralising antibodies. A test injection of 40 MU BTX-F was also given into the extensor digitorum brevis muscle (EDB), to examine the time course of the biological effect of the toxin electrophysiologically. Patients were followed up at two, four, eight, and 12 weeks.
All patients reported subjective improvement lasting from seven to 11 (mean 8.6) weeks accompanied by a significant reduction in mean clinical severity scores at two weeks. Four patients had pain which was substantially reduced. The electrophysiological studies confirmed biological sensitivity to the toxin in all patients, showing a significant change beginning at two weeks and returning to baseline at 12 weeks. The time course of this effect paralleled roughly that of the clinical response. The four patients who had previously received 520 MU BTX-F reported that the response was better and longer in duration with 780 MU. Dysphagia was more common than reported with the lower dose.
Better results are possible with higher doses of BTX-F but the duration of benefit is still shorter than with BTX-A, seemingly due to a shorter duration of neuromuscular junction blockade.
先前一项关于肉毒杆菌毒素F型（BTX-F）治疗斜颈的研究表明，520 MU的剂量是有效的，但持续时间比通常使用的肉毒杆菌毒素A型（BTX-A）短得多。目的是评估更高剂量的BTX-F的效果。
对先前治疗过的4名患者以及另外1名患者使用780 MU的更高剂量的BTX-F进行治疗。由于存在中和抗体，所有患者对BTX-A均为继发性无反应者。还向趾短伸肌（EDB）注射了40 MU的BTX-F进行试验注射，以电生理方式检查毒素生物效应的时间进程。在2周、4周、8周和12周对患者进行随访。
所有患者均报告主观改善持续7至11周（平均8.6周），同时在2周时平均临床严重程度评分显著降低。4名患者的疼痛明显减轻。电生理研究证实所有患者对毒素具有生物敏感性，显示在2周时开始有显著变化，并在12周时恢复至基线。这种效应的时间进程大致与临床反应平行。先前接受520 MU BTX-F治疗的4名患者报告称，780 MU的反应更好且持续时间更长。吞咽困难比低剂量时报告的更为常见。
更高剂量的BTX-F可能会取得更好的效果，但受益持续时间仍比BTX-A短，这似乎是由于神经肌肉接头阻滞的持续时间较短。
