Efficacy and tolerability of intranasally applied dimetindene maleate solution versus placebo in the treatment of seasonal allergic rhinitis.

The aim of this study was to investigate the efficacy and tolerability of a 0.1% dimetindene maleate spray (Fenistil Nasal Dosierspray) compared to placebo when applied intranasally. Dimetindene (dimetindene maleate, CAS 3614-69-5, DMM) is a very potent and well established H1-receptor antagonist. A total of 36 asymptomatic patients (17 female, 19 male), suffering from seasonal allergic rhinitis from grass pollen, were randomly assigned to treatment with matching topicalnasal sprays with either dimetindene maleate 0.1% or placebo as control in a double-blind, randomised, cross-over-design, with 2 weeks wash-out periods between. The trial period was chosen in a pollen-free time from 20th October to 5th November 1998 to guarantee asymptomatic patients. The patients being allergic to grass pollen, verified by positive case history, positive skin prick test and positive nasal provocation test, were challenged under controlled conditions with purified airborne grass pollen in the Vienna Challenge Chamber. The nasal spray were applied as single doses (1 puff = 0.14 ml of the respective solution with or without 0.14 mg dimetindene maleate) in the evening before at 7.30 p.m. and in the morning at 7.30 a.m. to each nostril exactly 15 min before the onset of allergen provocation. The dosage scheme relates to a daily dose of 0.56 mg DMM in the active treatment group. Subjective nasal and ocular symptoms were measured on-line in time intervals of 30 min during the 4 h allergen provocation. The statistical analysis was a priori sequentially ordered to account for multiple testing and keep the 5% level of significance. All measured primary criteria, Total Nasal Symptom Score (p < 0.0001) calculated from the three single symptoms running of the nose (p = 0.0032) sneezing stimulus (p < 0.0001) and nasal itching (p < 0.0001), as well nasal secretion (p = 0.0031), resulted consistently in a statistically significant and clinically relevant superiority of 0.1% DMM compared to placebo. The same superior treatment effect was observed for all the other criteria, despite the nasal flow, but including the ocular variables. This can be interpreted as a positive efficacy also in secondary allergic conjunctivitis. No systemic or topical adverse events were reported. The results of the study demonstrate that 0.1% DMM as nasal spray is an efficient and safe application form for patients suffering from seasonal allergic rhinitis.