Use of high-dose botulinum A toxin in benign essential blepharospasm: is too high too much?

Botulinum toxin (Botox) is the mainstay treatment for benign essential blepharospasm. Current treatment practice appears restricted by several reports demonstrating adverse effects and resistance to high-frequency, higher-dose therapy. This study aimed to explore whether high-dose, high-frequency treatments could be used without developing secondary resistance and without significant side-effects in patients refractory to conventional Botox doses. From a cohort of 120 patients being treated with Botox therapy for benign essential blepharospasm and idiopathic hemifacial spasm, case notes from six patients were retrospectively examined. In these patients, therapy had exceeded the recommended 50 units per side for a duration greater than 12 months and at less than 3 monthly intervals. Patterns in subjective severity grading and percentage of improvement as well as reported side-effects were analysed. All patients described greater than 60% improvement and 0-2 severity grading over a 3- to 15-year period with no evidence of secondary resistance. Side-effects were minor, transient and less frequently reported at higher doses. In a select group of patients, Botox therapy can be used effectively at doses higher than recommended over long periods with minimal side-effects and little evidence of secondary resistance.