Flunisolide, a derivative of fluocinolone acetonide, is advocated for intranasal inhalation for the treatment of perennial and seasonal allergic rhinitis. It is rapidly absorbed by all routes of administration, but it quickly undergoes extensive first-pass metabolism to a 6 beta-hydroxylated metabolite, which possesses only weak corticosteroid effects. Intranasal flunisolide relieves nasal symptoms (but not eye symptoms) in both perennial and seasonal allergic rhinitis, being most effective in patients who have an allergic component to their rhinitis; and like other corticosteroids it may reduce the need for systemic antihistamines in such patients, expecially during peak pollen periods. A few well designed comparative studies have shown flunisolide to be as effective as intranasal beclomethasone, and (in a single study) more effective than intranasal sodium cromoglycate solution. Only transient side effects have occurred, including nasal stinging and throat irritation. No Candida infections have been clinically apparent in short or longer term trials. Resting morning plasma cortisol levels have not been suppressed by usual therapeutic doses of intranasal flunisolide, but the drug's effects on hypothalamo-pituitary-adrenal (HPA) axis integrity during conditions of stress have not been evaluated.