The effect of azelastine on basal forced expiratory volume in one second in asthmatics: a systematic review and...

Nearly 5 to 10% of asthmatics show a problematic drug tachyphylaxis, featuring the need for new therapies. Bitter taste receptors (TAS2Rs) are expressed in the airway tract, and their activation leads to multiple antiasthma effects. Azelastine, an antihistaminic drug with a strong bitter taste, is used to treat allergic rhinitis but is frequently prescribed for asthma. The present study aims to evaluate the bronchodilator effect of azelastine in asthmatic patients. We searched PubMed, the Cochrane Library, and Scopus databases from inception to April 1, 2026. Studies investigating the effect of azelastine on baseline forced expiratory volume in one second (FEV1) of asthmatic patients, compared to a placebo, were included. Mean differences between the two arms were calculated using a random effects model. The systematic search retrieved 145 articles, of which 8 met the inclusion criteria. Azelastine improved FEV1 by 7.57% compared to placebo (p<0.001). The heterogeneity was low (I2=0%), and the overall methodological quality of the selected studies was high, except in four studies, where a risk of bias was observed due to deviations from the intended intervention. Meta-regression analysis showed no significant impact of age, sex ratio, and baseline FEV1 on the global effect size (p>0.05). Azelastine treatment improves FEV1 in asthmatic patients. These results support the previously reported bronchodilator benefits of azelastine through TAS2Rs activation. However, more clinical studies are still needed to explore the therapeutic potential of TAS2R-targeted treatments in asthma.