A two-center randomized, comparative study versus loratadine was conducted to examine the efficacy and safety of mizolastine in chronic idiopathic urticaria (CIU) compared with loratadine.

This trial followed GCP guidelines. 145 adult CIU patients completed mizolastine (M) 10mg (71/145) and loratadine (L) 10mg (74/145) once daily for 28 days. 9 patients withdrew or dropped out. The symptom relief was analysis according to symptom score reducing index came from patients' diary data. Adverse drug reaction (ADR) findings were completed by the information from inquiry, physical examination, laboratory tests (liver and renal function, blood and urine routine test) and ECG. A specialist on ECG was invited to join in this trial.

The score decrease of wheal in M group was superior to that in L group (p<0.05). Efficacy assessment showed that the efficacy of mizolastine was 90.1% and the excellent rate was 52.1%, while the efficacy of loratadine was 85.1% and the excellent rate was 45.9%. The incidence of ADR was 21.1% in M group and 34% in L group. No serious adverse event was reported.

The results confirm that mizolastine is effective and well tolerated in CIU treatment. The efficacy of mizolastine is similar to loratadine. However, mizolastine provided greater improvement in wheal reducing than loratadine.