Dimethindene maleate in the treatment of sunburn. A double-blind, placebo-controlled pilot study

The efficacy of topical dimethindene maleate (DMM, CAS 31614-69-5, Fenistil Gel) in the treatment of sunburn was evaluated in a placebo-controlled, 1-period crossover trial in 24 healthy volunteers. An UV-erythema (sunburn) of a well-defined intensity and extent was experimentally induced on three different skin test-areas by means of UV-A/B irradiation with three times the minimal erythema dose (MED). About 24 h after irradiation, one skin test-area was subjected to a 1-h occlusive treatment with DMM gel, the second test area was subjected to treatment with a placebo gel and the third one remained untreated. As objective-quantitative indicators of tenderness, a key symptom of sunburn, sensory and pain thresholds to CO2-Laser stimulation and laser somatosensory evoked potentials (SEPs) in Vertex-EEG were assessed about 1.5 h postdose. The reaction times (RTs) to painless and painful CO2-laser stimulation (sensory and pain threshold level, respectively) on the DMM-treated area were significantly longer than RTs to stimulation on the placebo-treated area. Thresholds in terms of laser energy showed no differences between the treatments. The SEP N1-amplitude on the DMM-area was markedly decreased in comparison to placebo. With regard to subjective sensations of pain, itching and tenderness assessed by means of visual analogue scales (VAS), no clinically relevant differences between treatments were observed after sole UV-irradiation. After additional laser stimulation tenderness was--objectively but not subjectively--decreased on the DMM-area versus placebo. Both gel preparations were well tolerated.