The effect and risk of NEURONOX should be consulted by a physician. Attention should be paid to any signs and symptoms of adverse events. The immediate medical support should be sought when a patient experiences shortness of breath, muscle weakening or difficulty in swallowing or speaking, after the treatment. Adverse events may appear within couple of hours or weeks after the treatment. Patients with blepharospasm may have been extremely sedentary for a longtime. Such patients should be cautioned to resume activity slowly and carefully after the administration of NEURONOX. NEURONOX blocks neuromuscular transmission binding to acceptor sites on motor nerve terminals, entering the nerve terminals, and inhibiting the release of acetylcholine. When injected intramuscularly at therapeutic doses, NEURONOX produces partial chemical denervation of the muscle resulting in a localized muscle activity reduction. In addition, the muscle may atrophy, axonal sprouting may occur, and extra junctional acetylcholine receptors may develop. There is evidence that reinnervation of the muscle may occur, thus slowly reversing muscle denervation produced by NEURONOX. The paralysis activity of botulinum toxin is effective for the relief of excessive abnormal contraction associated with blepharospasm.
In case of other botulinum toxin product which was injected to the neck muscle, the botulinum toxin treatment mitigated subject and objective symptoms of paroxysmal spasmodic tonicollis and reduced the rotation angle of head as well as the rising of shoulder. And it also reduced the size and the intension of hypertrophic muscles and relieved the pain. In case of other botulinum toxin product, the efficacy of the botulinum toxin product has not been established in case of deviations over 50 prism diopters, or restrictive strabismus, or Duane's syndrome with symptoms of contralateral superior recurs weakness, or secondary strabismus caused by over-recession of the antagonist muscle during the surgery and repetitive injection may be required.
In case of other botulinum toxin product, botulinum toxin was ineffective in chronic paralytic strabismus except when used in conjunction with surgical repair to reduce antagonist contracture. If neutralizing antibodies to botulinum toxin type A is exist, it may reduce the effectiveness of botulinum toxin treatment. In clinical studies, reduction in effectiveness due to antibody production has occurred in one patient with blepharospasm receiving 3 doses of botulinum toxin over a 6 weeks period totaling 92 U, and in several patients with torticollis who received multiple doses experimentally, totaling over 300 U in a one month period. For this reason, the cumulative dose of NEURONOX treatment in a one month period should not exceed 200 Units for treating blepharospasm.