Double-blind comparison of nedocromil sodium (1% nasal spray) and placebo in rhinitis caused by birch pollen.

A double-blind parallel group study was undertaken during May and June 1985 to compare the effect of nedocromil sodium (1% nasal spray) and placebo, taken twice daily, in relieving the symptoms of rhinitis caused by birch pollen. Two centres were involved. The 54 patients studied had a history of rhinitis in 2 previous birch pollen seasons and positive skin tests to birch pollen. Patients were treated for 4 weeks, but to compare the effects of the 2 treatments the peak pollen periods were used. For dairy card symptoms, results in the 2 centres differed: in Tampere, there were trends in favour of nedocromil sodium with respect to itching (P = 0.04, sneezing (P = 0.06) and total symptoms (P = 0.09); in Oulu no significant differences were seen. Nasal peak expiratory flow rates were slightly better in the nedocromil sodium group. In respect of antihistamine usage, results in the 2 centres were similar and significantly more were used in the placebo group (P less than 0.01). At the end of the trial, both the patients' and the investigators' opinions of treatment effect favoured nedocromil sodium. There were no serious side effects. The results suggest that nedocromil sodium 1% nasal spray, when given twice daily, is effective in the treatment of seasonal allergic rhinitis.