Comparisons among HC 20-211 (Ketotifen), clemastine, DSCG and beclomethasone dipropionate in nasal challenge.

Nasal challenge tests were used to compare the protective effect of pre-treatment with HC 20-511 (Ketotifen), a new antiallergic compound, clemastine, DSCG and beclomethasone dipropionate in 14 patients with hay fever. HC 20-511 and clemastine were tested in a double-blind fashion and DSCG and beclomethasone openly. Most of the patients experienced an intense nasal reaction when challenged with pollens without pre-treatment. The intensity of nasal reactions was determined by subjective symptoms, clinical findings and nasal peak expiratory flow values. All the drugs tested relieved the symptoms and signs induced by pollens in nasal challenge tests. This tendency was not, however, statistically significant for any of the drugs. When using the changes in nasal expiratory flow rate as a criterion of protectiveness, the differences among the compounds tested were also slight. HC 20-511 seems to be a promising antiallergic agent. However, long term clinical trials still are needed to establish its efficacy in various allergic disorders.