Clinical study of the therapeutic efficacy and safety of emedastine difumarate versus terfenadine in the treatment of seasonal allergic rhinitis.

Emedastine is a new H1-receptor antagonist endowed with potent and selective antihistamine activity. The aim of this study was to evaluate the therapeutic efficacy and tolerability of emedastine difumarate (CAS 87233-62-3) in Caucasian patients in the treatment of seasonal allergic rhinitis as compared to terfenadine (CAS 50679-08-8). A total of 130 patients suffering from grass pollen allergic rhinitis were randomly assigned to 14 days treatment with either emedastine difumarate (2 mg b.i.d.) or terfenadine (60 mg b.i.d.) in a double-blind, randomised, crossover design. Primary efficacy parameter was a Total Severity Symptom Score, including among symptoms nasal congestion, sneezing, rhinorrhea, nasal/throat/palate itching, eye itching and lacrimation. Safety was assessed on routine laboratory tests and recording vital signs and adverse events (AEs). Emedastine 2 mg b.i.d. was significantly more effective than terfenadine 60 mg b.i.d. in reducing Total Symptom Severity Score (p = 0.0258). This statistical significant difference was also obtained in controlling sneezing and rhinorrhea (p = 0.003). Moreover, both the physician and patients indicated emedastine as the preferred therapy (p < 0.01). Forty-seven drug related AEs were reported for emedastine (= 51.07 %) and 53 for terfenadine (64.15 %), most of them involving the CNS. The results of study show that emedastine difumarate is more effective than terfenadine in the symptomatic management of seasonal allergic rhinitis and is particularly active in controlling the main nasal symptoms, such as sneezing and rhinorrhea; it is safe and well tolerated in this therapeutic indication, while related AEs are less if compared to those displayed by terfenadine.