A Comparative Study of Montelukast and Azelastine add on Therapy in Moderate to Severe Allergic Rhinitis Treatment: A Double-Blind Randomized Clinical Trial.BACKGROUND
 Allergic Rhinitis (AR) is a prevalent chronic inflammatory nasal condition with significant negative effects on the patients' quality of life.  This study aimed to investigate the efficacy of Montelukast and intranasal antihistamine in combination with intranasal corticosteroid (INCS) in moderate to severe allergic rhinitis on the patients' quality of life and AR control.


 This double-blind randomized clinical trial study was carried out on 66 moderate to severe AR patients referred to Namazi Hospital, Shiraz, Iran from 2020 to 2021, who were randomly divided into 3 groups.  Group one received Montelukast add-on therapy and Budesonide nasal spray.  The second group received intranasal antihistamine (Azelastine) add-on therapy and Budesonide nasal spray and the third group as the control group received intranasal Budesonide spray with a placebo tablet.To measure the impact of each medication on the patient's quality of life and AR control, we employed the Sino-Nasal Outcome Test-22 questionnaire (SNOT 22).  We evaluated the symptoms and compared them at baseline, one and three months after the start of treatments.  Spirometry was performed to investigate the possibility of co-morbid asthma at baseline and end of the study.


 Most patients experienced perennial AR (65.2%).  Reduction of mean scores SNOT22 was statistically different between groups (P-value < 0.001).  Three months after treatment, the mean decrease of SNOT-22 in the Azelastine group was statistically significant compared to both Montelukast (P-value < 0.001) and control groups (P-value < 0.001).  No significant difference was observed between the Montelukast and control groups (P-value = 0.142).  The amount of FEV1 change after AR treatment was not statistically significant between the groups in asthmatic patients (P-value = 0.351).


 CONCLUSION
 Based on our findings, we recommend Azelastine in conjunction with an intranasal corticosteroid for the treatment of moderate to severe allergic rhinitis.  In moderate to severe AR or even asthma management, Montelukast has no greater impact than INCS.
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