Antihistamine selection in patients with allergic rhinitis.

Seven hundred eighty-two patients diagnosed as having either seasonal allergic rhinitis or perennial allergic rhinitis in a solo allergy practice were given five different antihistamine products representing each of the five classes of antihistamines. The following products were evaluated for 2 weeks each: tripelennamine, diphenhydramine, chlorpheniramine, hydroxyzine, and trimeprazine. Symptoms and side effects were graded 0 to 4. The more troublesome side effects, graded 3 or 4, were tabulated. The antihistamine products in order of increasing frequency of significant side effects were: trimeprazine, chlorpheniramine, hydroxyzine, diphenhydramine, and tripelennamine. The order of antihistamine preference by the patients was chlorpheniramine (27%), diphenhydramine (22%), tripelennamine (20%), hydroxyzine (16%), and trimeprazine (14%). Only seven of 758 patients (less than 1%) were unable to find an acceptable antihistamine class. Patients remained on their antihistamine class of first choice 78% of the time after 1 year, 71% after 3 years and 51% after 5 years. The antihistamine pack provides a rational approach to antihistamine selection in patients with allergic rhinitis.