Randomised controlled trial of butterbur and cetirizine for treating seasonal allergic rhinitis.

OBJECTIVES To compare the efficacy and tolerability of butterbur (Petasites hybridus) with cetirizine in patients with seasonal allergic rhinitis (hay fever). DESIGN Randomised, double blind, parallel group comparison. SETTING Four outpatient general medicine and allergy clinics in Switzerland and Germany. PARTICIPANTS 131 patients were screened for seasonal allergic rhinitis and 125 patients were randomised (butterbur 61; cetirizine 64). INTERVENTIONS Butterbur (carbon dioxide extract tablets, ZE 339) one tablet, four times daily, or cetirizine, one tablet in the evening, both given for two consecutive weeks. MAIN OUTCOME MEASURES Scores on SF-36 questionnaire and clinical global impression scale. RESULTS Improvement in SF-36 score was similar in the two treatment groups for all items tested hierarchically. Butterbur and cetirizine were also similarly effective with regard to global improvement scores on the clinical global impression scale (median score 3 in both groups). Both treatments were well tolerated. In the cetirizine group, two thirds (8/12) of reported adverse events were associated with sedative effects (drowsiness and fatigue) despite the drug being considered a non-sedating antihistamine. CONCLUSIONS The effects of butterbur are similar to those of cetirizine in patients with seasonal allergic rhinitis when evaluated blindly by patients and doctors. Butterbur should be considered for treating seasonal allergic rhinitis when the sedative effects of antihistamines need to be avoided.