Frozen versus fresh reconstituted botox for laryngeal dystonia

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To compare the efficacy and side effects of frozen versus fresh reconstituted botulinum toxin type A (BTX-A) in the treatment of laryngeal dystonia.


Prospective open-label crossover study; 43 adult patients with adductor spasmodic dysphonia were randomly treated with fresh or refrozen reconstituted BTX-A at a private voice center. Treatment outcomes were assessed by duration of action and self-rated satisfaction (7 point Likert scale). Side effects of breathiness and dysphagia for liquids were assessed as well.


There was no statistically significant difference in the duration of action (mean, 16.2 ± 8.5 vs 16.0 ± 7.6 weeks) and self-rated satisfaction of the treatment (median, 6.0 vs 6.0 points). The side effects were similar for both BTX-A injection types. In addition, there were no instances of infection for refrozen injections.


BTX-A may be safely used after being reconstituted and frozen or refrozen without a significant loss of effectiveness or additional side effects. In our experience, the period of freezing was on 2 occasions for up to 8 weeks.


Refrozen BTX-A may be a cost-effective use of an expensive drug.


EBM rating: B-2b

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