This double-blind, multicentre study was designed to compare the efficacy and tolerability of
terfenadine 120 mg with
cetirizine 10 mg, each taken once daily, in the treatment of
seasonal allergic rhinitis. Two hundred and eighty-five patients were recruited to the study by nine general practice centres in the south of England during the 1989
hay-fever season. Symptom severity was assessed daily by the patient and before and after the one-week treatment period by the investigator. At the second
clinic visit both patient and investigator assessed the overall response to treatment. The two treatment groups were well matched for all demographic variables and baseline symptom scores. Improvement in all seven symptoms (nasal congestion,
sneezing, rhinorrhoea,
itching nose,
itching eyes, watery eyes and red eyes) and overall response to treatment were similar in both treatment groups. Adverse events were mainly of mild to moderate severity and were reported by 14 patients on
terfenadine and 21 patients treated with
cetirizine (p = 0.317). This study confirmed
terfenadine's role as the treatment of choice in
hayfever. A single 120 mg dose in the morning effectively reduced symptoms by 43 to 70 per cent of baseline values, with an acceptably low incidence of side effects.
Cetirizine at a single dose of 10 mg displayed equal efficacy in controlling
hayfever symptoms but, in common with other studies, had a significantly greater incidence of drowsiness (p = 0.046).