Efficacy and Safety of Concomitant Montelukast Sodium and Levocetirizine Dihydrochloride in Perennial Allergic Rhinitis (PAR) Patients

Inclusion Criteria:

• Patients with at least 2 years history of PAR prior to the study

• Positive results of skin prick test

• Patients who provided a signed written informed consent form

• Patients who are able and willing to complete subject diaries

• Patients who agree to maintain consistency in their surroundings throughout the studyperiod

• At Visit, 2 patients whose symptom scores recorded in the subject diary meet all ofthe followings during the last one week of baseline period A.Daily mean of 6 points orabove for Daytime Nasal Symptom Score (maximum 12 points) B.Daily mean of 1.8 pointsor above for Daytime Nasal Obstruction Symptom Score (maximum 3 points)

Exclusion Criteria:

• Patients also with non-allergic rhinitis with different causes.

• Patients with severe asthma who meet the followings.

• Presence of nasal polyps or any clinically important nasal anomaly.

• History of acute • chronic sinusitis within 30 days of Visit 1

• History of intranasal / eye surgeries within 3 months of Visit 1

• Initiation of immunotherapy or dose modification within 1 month prior to Visit 1

• Upper respiratory infections including cold and systemic infections within 3 weeks ofVisit 1.

• Chronic use of tricyclic antidepressants, beta agonists, bronchodilators, etc. thatmay affect the efficacy of study drug

• At Visit 2, patients who recorded Daytime Nasal Symptom Scores for fewer than 4 daysin the subject diary during the last one week of baseline period