Protective effect of hydroxyzine and phenylpropanolamine in the challenged allergic nose.

Allergic rhinitis patients were challenged with intranasal allergen aerosols after pretreatment with hydroxyzine and phenylpropanolamine, singly and in combination. Hydroxyzine protected against itching, sneezing and hypersecretion but aggravated obstruction. Phenylpropanolamine had a subtle but measurable anti-congestive effect. This model quantitates and confirms the complementary effects of combined antihistamine-decongestant therapy.