Sumatriptan Iontophoretic Transdermal System Reduces Treatment-Emergent Nausea and is Effective in Patients with and Without Nausea at Baseline - Results from a Randomized Controlled Trial

Objectives To test the hypothesis that sumatriptan iontophoretic transdermal system (TDS) is associated with lower rates of treatment-emergent nausea (TEN) relative to placebo, as well as to compare the efficacy of sumatriptan TDS in migraineurs with or without nausea at baseline. Methods Participants of a double-blind, randomized, parallel-group, single-attack, placebo-controlled study conducted at 38 sites in the United States were analyzed. Participants who treated their migraine attacks while nausea-free were identified. The primary endpoint was TEN over 24 hours post-treatment contrasting both treatment groups and it was assessed by regression analyses using generalized estimating equations. Secondary endpoint was headache response as a function of presence of nausea, assessed by generalized linear model. Results A total of 130 participants free of nausea at baseline were treated with sumatriptan TDS, while 109 participants free of nausea at baseline were treated with placebo TDS. The occurrence of TEN over 24 hours post-treatment was significantly lower with the sumatriptan TDS than with placebo (P =.0011). These differences were statistically significant at 1 hour (13.8% vs 9.2%, P <.01), 2 hours (13.8% vs 4.6% P <.001) and 3 hours (13.8% vs 8.5% P <.01). The efficacy of sumatriptan TDS was similar regardless of the presence or absence of nausea at baseline for all clinical parameters. Conclusion Sumatriptan TDS is not associated with the emergence of nausea in migraineurs without nausea. It is equally effective in participants with or without nausea at the time of treatment.