Azelastine nasal spray

Azelastine is an H1-receptor antagonist. This entry represents the product delivered locally inside the nose, not an oral or systemic formulation. Its current U.S. Drug Facts label describes it as an antihistamine for specified nasal symptoms attributed to hay fever or other upper respiratory allergies.

A double-blind placebo-controlled trial randomized 581 people with perennial allergic rhinitis to two intranasal azelastine formulations or placebo. The primary measurement was change in a participant-reported composite of nasal symptoms. The study supplies randomized evidence for a local allergic-rhinitis product, but it did not measure mast-cell mediators and did not enroll people with MCAS.

A separate historical randomized crossover compared oral azelastine with chlorpheniramine in 15 people with mastocytosis. It recorded symptom scores, skin-test responses, plasma histamine, and global evaluations. Some skin-response and symptom measurements differed between the regimens, plasma histamine did not, and the authors reported that neither drug was clearly superior when all parameters were considered. Because that exposure was oral and the comparator was another H1 antihistamine, it is preserved here as a route boundary rather than treated as evidence for the current nasal spray.

The catalog therefore places azelastine nasal spray under “Local-route symptom treatments.” The placement records what was studied and what product is currently labeled; it does not imply systemic mast-cell stabilization or a general MCAS outcome.