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Botulinum toxin A delivery methods for upper face equally effective

Subcutaneous injection and intramuscular administration of botulinum toxin A were equally effective in treating the upper face, according to recent study results.

Researchers at Thomas Jefferson University Hospital, Philadelphia, conducted a double blind, prospective study between December 2010 and June 2011 of 19 patients who underwent botulinum toxin A (Botox, Allergan) treatment to the forehead. All patients randomly received intramuscular (IM) administration of botulinum toxin to one side of the face and a subcutaneous (SC) injection of botulinum toxin to the other side for a combined 12 U Botox.

Eyebrow elevation assessment was made at baseline and 2 weeks, 2 months and 4 months after injections. Patient questionnaires on discomfort during injection, bruising and tenderness, and perceptions of appearance were compiled after treatment.

Eyebrow height measurements between injection methods displayed no difference (0.00; 95% CI, –0.02 to 0.01) at first follow-up visit. In the final follow-up, the measurements also showed no difference between methods. Patients reported IM injections caused greater discomfort when compared with SC injections (–0.76; 95% CI, –1.53 to 0.0005).

“Patient satisfaction scores did not demonstrate a statistically significant difference between IM injections compared with SC techniques when measured on the first and second post-treatment visits; however, there was a trend toward significance on the final follow-up visit [P=.04],” the researchers reported.

“Subcutaneous injection of botulinum toxin A is equally effective in achieving paralysis of the underlying frontalis muscle as IM botulinum toxin A administration,” researchers said. “Patients report less discomfort on injection of botulinum toxin into the SC plane relative to the IM space. Subcutaneous injection can therefore be used as a technique to mitigate the pain associated with IM injection of botulinum toxin A without compromising the compound’s efficacy.”

Disclosure: The researchers report no relevant financial disclosures.