What is the best prescription allergy medicine?

Intranasal steroids: For environmental allergies, the most effective treatment is nasal steroid sprays. Some are approved to as young as age 2 years old, there are generic ones available. There is a possibility that these may not require a prescription in the near future.

Nasal steroids: As long as you are talking about allergic rhinitis, nasal steroids have shown in studies to provide the greatest amount of relief. As far as cost-effectiveness goes, i would use generic flonase, which is going to be preferred on most plans.