Abstract: Objective To evaluate the efficacy and safety of mizolastine versus loratadine in the treatment of chronic idiopathic urticaria(CIU).Methods A five-centre,double-blind,randomized,comparative study was conducted.The patients were randomly divided into two therapeutic groups:received mizolastine(10mg)or loratadine(10mg)once daily for 28 days.Itching,number of wheals,diameter of the largest wheal and lasting time of urticarial attacks were evaluated.According to a scale from 0(absent)to 3(severe),the patientrated severity of itch measured by visual analogue scale(VAS).The number of weekly urticaria episodes was recorded.Control visits were scheduled after 7,14 and 28 days of therapy.Results 213 patients were enrolled and206patients completed the trial,including 104 cases in mizolastine group and 102 cases in loratadine group.There were 12 patients withdrew and dropped out from the trial.Efficacy assessment based on symptom score reducing index(SSRI)showed that the effective rate of mizolastine and loratadine were 80.8% and 74.5% respectively,no statistically significant difference was observed 28 days after treatment between two groups(χ²=1.16,P=0.28).The scores of the diameter of largest wheal,weekly urticaria episodes and VAS score in mizolastine group were decreased significantly than those in loratadine group 7 days after treatment(P=0.05,P=0.03and P=0.02).But there was no statistically significant different between two groups14and28days after treatment(P>0.05).No serious adverse events were reported in these two groups.The incidences of adverse event of mizolastine and loratadine were28.6%and25.5%respectively,there were no statistically significant difference between two groups(χ²=0.25,P=0.62).Conclusions The efficacy of mizolastine and loratadine is similar in the treatment of CIU,but mizolastine is quicker in action than loratadine.The incidences of adverse events are not different in the two groups.

Key words: Urticaria, Loratadine, Mizolastine