Botulinum toxin therapy for hyperhidrosis: reduction of injection site pain by nitrous oxide/oxygen mixtures

Injection site pain (ISP) reduces compliance of botulinum toxin (BT) therapy considerably. We wanted to study whether nitrous oxide/oxygen (NOO, Livopan®, Linde Gas Therapeutics, Unterschleißheim, Germany) can reduce ISP in patients receiving intracutaneous BT injections for axillary or palmar hyperhidrosis (HH). The study followed an open-label design comparing intraindividually ISP in both axillae and/or both palms when NOO was applied or not during BT injections. BT efficacy was measured by the Hyperhidrosis Disease Severity Scale (HDSS) and by a 4-point Self-Assessment Scale. ISP was documented by a Visual Analogue Scale (VAS) and the Verbal Scale of Pain Intensity (VSPI), adverse effects by a Structuralised Interview (SI). Altogether 13 patients (age 34.1 ± 12.4 years, 9 females, 4 males) were studied. 11 BT treatments were for biaxillary and 3 for bipalmar HH. BT reduced biaxillary HH from HDSS 3.7 ± 0.5 to 1.0 ± 0 and bipalmar HH from 3.6 ± 0.6 to 1.0 ± 0. All patients reported ISP reduction by NOO. In axillary HH, NOO reduced ISP from 55.7 ± 12.7 to 12.8 ± 7.5 on the VAS (p < 0.05) and from 4.1 ± 0.3 to 0.7 ± 0.5 on the VSPI (p < 0.05), in bipalmar HH from 60.0 ± 10.0 to 13.3 ± 5.8 on the VAS (p < 0.05) and from 5.0 ± 0 to 1.3 ± 0.5 on the VSPI (p < 0.05). Adverse effects were not identified. NOO is a potent, non-sedative, quickly reversible and safe inhalative analgesic which reduces ISP considerably in patients receiving BT therapy for axillary and palmar HH thus substantially improving compliance of BT therapy.