The effect of botulinum toxin type A injection in decreasing intratunnel tendon tension in carpal tunnel syndrome: a randomized controlled trial for efficacy and safety

Abstract

Citation: Kaufman-Janette, J.; Cox, S.E.; Dayan, S.; Joseph, J. Botulinum Toxin Type A for Glabellar Frown Lines: What Impact of Higher Doses on Outcomes? Toxins 2021, 13, 494. Abstract: Botulinum toxin serotype-A (BoNT-A) preparations are widely used to improve the appearance of wrinkles. While effective and well tolerated, patients require retreatment over time to re-establish the effects. There is growing interest from patients as to whether higher doses can prolong response without significantly increasing side effects. We reviewed the efficacy and safety evidence for high-dose BoNT-A treatment of glabellar lines, by evaluating high-dose studies published since 2015. Toxins approved for glabellar line treatment in the US or Europe were considered. "High-dose" indicated doses above the licensed dose for each BoNT-A preparation. Five studies met the inclusion criteria and most were randomized, double-blind trials; designs and population sizes varied. Findings suggested that higher-dose BoNT-A treatment is feasible and may improve response duration without increased safety issues. Around 9 months' median duration was achieved with a 2-2.5-fold increase of the abobotulinumtoxinA on-label dose, or with a 5-fold increase in incobotulinumtoxinA dose. A 2-4-fold increase of the onabotulinumtoxinA on-label dose yielded a median duration of around 6 months. Importantly, patient satisfaction and natural look remained with increasing abobotulinumtoxinA doses. While more data are needed, these findings may lead to more effective, individually tailored treatment plans to meet patient expectations. Key Contribution: A review of available data indicates that higher doses of BoNT-A preparations than are currently used as standard may prolong duration of response in glabellar lines without increasing side effects. A ceiling dose likely exists for each BoNT-A preparation, but more data are needed. Ultimately, individual-tailored treatment plans with less frequent need for retreatment may be feasible in the future.