Use of botulinum toxin type F injections to treat torticollis in patients with immunity to botulinum toxin type A.

Fifteen patients with torticollis who had been treated with repeated injections of botulinum toxin type A (botox A) developed antibodies to the toxin. This resulted in loss of benefit in the 13 patients who had improved with botox A injections and failure to develop muscle atrophy after injection in all 15 patients. Patients were then injected with botulinum toxin type F (botox F) in the same muscles that had been injected with botox A. Ten of the 15 improved after botox F injections, including 9 of the 12 patients who had improved with type A toxin. Six of 9 patients with pain had improvement in pain after botox F injections. Patients reported similar improvement with type F and type A toxins, but duration of benefit was approximately 3 months with type A and approximately 1 month with type F. Botox F is an effective treatment for torticollis in patients who are immune to botox A. The usefulness of type F toxin, however, is limited by short duration of benefit.