All of the preparations are effective. A patient must find a preparation that they tolerate and they should stick with that. We tend to use nasal steroids as first or second line drugs in the treatment of allergic rhinitis. Antihistamines are the other major class of oral medications used to treat allergic rhinitis. Antihistamines work by blocking the action of histamine at histamine receptors.
Histamine is responsible for the itching, swelling and increased mucus secretion.
Antihistamines are usually divide into the sedating variety and the nonsedating variety. There are no nonsedating preparations available over the counter. The following nonsedating preparations are available. Claritin Zyrtec Allegra Claritin and Zyrtec are both once daily preparations and Allegra is a twice daily preparation. There are few head to head comparisons of the above medications.