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Botox injections above 100 U appear effective for some refractory blepharospasm patients
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Patients with refractory essential blepharospasm may benefit from treatment with botulinum toxin type A at doses higher than the standard 100 U injections, a prospective study suggests.
Richard L. Levy, MD, and colleagues at Wilmer Eye Institute evaluated the efficacy of increased botulinum toxin type A (Botox, Allergan Inc.) in eight consecutive patients with essential blepharospasm or Meige's syndrome. All patients had been receiving bilateral 50 U botulinum toxin injections bimonthly for at least 6 months. Upon enrollment, researchers increased patients' dosages to either 62.5 U or 75 U per side, with repeat injections administered at least 14 days apart.
Investigators found all patients generally tolerated the supramaximal doses. No vision- or life-threatening adverse events were reported, and no patients reported experiencing adverse events, such as rash, diplopia or increased facial weakness, according to the study.
Four patients opted to continue receiving the supramaximal dosing regimen, three of whom had Meige's syndrome. Among these patients, the average time between repeat injections improved from 68 days to 90 days. Two patients reported improved reading ability and one patient reported less awareness of their condition, as well as an improvement in measures of quality of life.
The remaining four patients opted to return to 100 U injections, although intervals between injections increased from 72 days to 90 days. One patient noted she was less aware of her condition. However, the remaining three patients reported no change or increased difficulty with shopping or driving, according to the study.
"It may be that patients with Meige's syndrome are so debilitated from their condition that any improvement significantly improves their overall quality of life, whereas patients with isolated [essential blepharospasm] have higher expectations," the study authors said.
In contrast to prior studies, no patients in the current study experienced an increased incidence of ptosis from the higher botulinum toxin doses. This may be due to the study's injection protocol, which involved injections above the eyebrows and in the lateral canthal regions rather the upper eyelids, the authors noted.
The study is published in the September issue of Ophthalmology.