The efficacy and side effects of once-daily astemizole-D, a combination of 10 mg astemizole and 240 mg pseudoephedrine, were compared with those of twice-daily brompheniramine-D, a combination of 12 mg brompheniramine and 50 mg phenylpropanolamine (Lunerin), in 64 patients with seasonal allergic rhinitis caused by birch pollen. Efficacy was monitored by patient's diary scores, investigator ... [Show full abstract] assessments of nasal and eye symptoms and need of rescue medication during the 4-week study period. Both astemizole-D and brompheniramine-D reduced nasal and eye symptoms of allergy. There were no significant differences between the treatment groups regarding obstruction, but brompheniramine-D alleviated symptoms of rhinorrhoea and itchy eyes significantly more than astemizole-D. On the other hand, the patients in the brompheniramine-D group reported dry mouth, tiredness and drowsiness more often than those in the astemizole-D group. The results indicate that the two drugs are effective in the treatment of seasonal allergic rhinitis, but astemizole-D is better tolerated than brompheniramine-D.