Hypothalamic-pituitary-adrenal axis suppression during inhaled or intranasal corticosteroid treatment

Asthma and chronic rhinitis frequently coexist. In such patients, the risk of adverse side effects of corticosteroids, among the most common agents for both conditions, is high. The major adverse reaction of both inhaled and intranasal corticosteroids is suppression of the hypothalamic-pituitary-adrenal (HPA) axis with resultant corticosteroid imbalance. Inhaled corticosteroids pose a greater threat of adverse event because of the higher systemic drug concentration achieved by this route. When inhaled, doses of beclomethasone dipropionate as high as 3 mg/d can be tolerated without HPA-axis suppression. In contrast, HPA-axis suppression has occurred following a single inhaled dose of 0.25 mg of fluticasone propionate or 0.8 mg of budesonide. Despite the relative safety of intranasal corticosteroids, HPA-axis suppression has followed doses as low as 0.4 mg/d of budesonide or 0.2 mg/d of fluticasone propionate for 1 week. Because individual susceptibility to HPA-axis suppression during corticosteroid therapy varies widely among individuals, all patients taking these agents in either form should be regarded as being at risk.