SEDATION IN ALLERGIC RHINITIS IS CAUSED BY THE CONDITION AND NOT BY ANTIHISTAMINE TREATMENT

Sedation is regarded as a common side-effect of most H-1-antihistamine s. This view must be accepted, yet can hardly be assessed under treatm ent of allergic disorders. Since central sedative potency is hard to e valuate, different methods of measurement have been introduced in the four phases of clinical investigation. While tests of high complexity in early trials can detect true central effects, they seem to have the disadvantage of not taking into consideration the important interacti ons of drugs with the disorder. Therefore, we used a visual analog sca le (VAS) as an instrument to demonstrate sedative effects in five clin ical studies carried out between 1989 and 1994 with a total number of 1070 patients. Thereby, we could assess the result of the different co mponents of the central interaction. In 1989, in a double-blind, place bo-controlled trial, we could show that the vigilance of patients suff ering from seasonal allergic rhinitis increased significantly more und er treatment with an antihistamine (mizolastine) than under placebo. F rom 1992 until 1994, we compared azelastine nasal spray either by the double-dummy technique with oral antihistamines (cetirizine, loratadin e, and astemizole) or by the double-dummy or placebo-controlled design with monotherapy or combined therapy with azelastine tablets. A marke d or statistically significant improvement of vigilance was found for all compounds (loratadine: P <0.0001; cetirizine: P <0.0254; and azela stine nasal spray: P <0.1409 to P <0.0001). Even when taking azelastin e as oral application, patients, in spite of the warning, reported a s imilar increase in vigilance (P <0.2628 to P <0.0001). Finally, we ass essed the range of physiologic vigilance using the same VAS in healthy volunteers. In conclusion, we could prove that in all trials the base line values of vigilance of untreated symptomatic patients were far be low physiologic condition and improved under treatment to the upper ra nge of healthy persons. Therefore, any sedative properties of modern H -1-antihistamines should not limit their therapeutic use, since the tr uly threatening sedation results from the disorder itself.