Astepro, full-prescription strength allergy medicine, starts working in 30 minutes . This steroid-free allergy spray provides long-lasting allergy relief of indoor and outdoor nasal allergy symptoms; nasal congestion, runny nose, sneezing, and itchy nose for up to 24 hours. Astepro allergy has flexible dosing, so it can be used once or twice daily for allergy relief. One spray contains 205.5 mcg of azelastine HCl.