1. Dosage

Oral non-sedating antihistamines are FDA-approved for managing urticaria and allergic rhinitis. Nasal non-sedating antihistamines as monotherapy and combination therapy are FDA-approved for treating allergic rhinitis and vasomotor rhinitis. The oral non-sedating antihistamines desloratadine and acrivastine are available only by prescription. Inhalational non-sedative antihistamines are also available; olopatadine (Patanase®) and azelastine (Astepro®) are available by prescription and azelastine (Astepro Allergy ®) are available now over the counter.