Treatment of axillary hyperhidrosis with botulinum toxin type A reconstituted in lidocaine or in normal saline: a randomized, side-by-side, double-blind study.

BACKGROUND: Botulinum toxin type A represents a safe and effective treatment for primary axillary hyperhidrosis. One of the most troublesome disadvantages associated with this therapy is pain at the injection sites. Reconstitution of botulinum toxin A in a solution of lidocaine could be an easy alternative procedure to reduce the discomfort associated with those injections. However, the current recommendations are that botulinum toxin A should be reconstituted in normal saline.

OBJECTIVES: To compare the efficacy and tolerance profile of saline-diluted botulinum toxin A and lidocaine-diluted botulinum toxin A in patients with axillary hyperhidrosis.

METHODS: In a double-blind, side-by-side, controlled, randomized clinical trial, 29 patients were injected with 100 mouse units of botulinum toxin A (Botox); Allergan Pharmaceuticals Ireland, Westport, Ireland) reconstituted in lidocaine into one axilla and with the same dosage of the toxin, reconstituted in an equal volume of saline, into the other axilla. The patients were followed up for 8 months. Quantification of sweat production was performed by iodine-starch tests and by the patients' own rating of sweating. The intensity of pain associated with the botulinum toxin intracutaneous injections was self-assessed by the patients and was evaluated using a 100-mm visual analogue scale.

RESULTS: Botulinum toxin A diluted in normal saline and botulinum toxin A diluted in lidocaine were similarly effective in terms of control of onset of sweat production, duration of effect and subjective percentage of mean decrease in sweating. Both treatments were well tolerated, and there were no lasting or severe adverse effects. However, the mean +/- SD pain score during the procedure was significantly lower in the axillae treated with lidocaine-reconstituted botulinum toxin than in the axillae treated with saline-reconstituted botulinum toxin (29.3 +/- 20.1 vs. 47.5 +/- 24.0; P = 0.0027).

CONCLUSIONS: Short- and long-term results show the equal effectiveness of botulinum toxin A reconstituted in saline or in lidocaine. However, because injections of botulinum toxin A reconstituted in lidocaine are associated with significantly reduced pain, lidocaine-reconstituted botulinum toxin A may be preferable for treating axillary hyperhidrosis.