LYSINE-VASOPRESSIN IN THE EVALUATION OF THE HYPOTHALAMIC-PITUITARY-ADRENAL AXIS IN CHILDREN WITH ALLERGIC RHINITIS TREATED WITH INTRANASAL BECLOMETHASONE DIPROPIONATE OR ORAL PREDNISONE

One of the complications of steroid therapy is the hypothalamic-pituit ary-adrenal (HPA) axis suppression, particularly in children where thi s can lead to growth suppression and other well known complications. A lthough there are a large number of studies on suppression of the HPA axis with the use of topical steroids, the subject is still controvers ial. We measured the HPA axis function in 3 groups of allergic childre n treated with. 1) intranasal beclomethasone dipropionate (BDP) 400 mu g/day for 4 weeks or 2) BDP 800 mu g/day for 4 weeks and 3) oral pred nisone, 1 mg/kg/day for 2 weeks. The HPA response was obtained after l ysine-vasopressin (LVP) stimulation. LVP acts on the pituitary or hypo thalamus level, stimulating the whole axis. Peripheral blood samples t hrough an intravenous line were obtained for serum cortisol measuremen t at zero, 30, 60, and 90 minutes after the intravenous injection of L VP, before and after the treatment period. Our results showed no suppr ession of the HPA axis in children medicated with BDP at either 400 mu g/day or 800 mu g/day. On the other hand, there was a suppression of the HPA axis after prednisone treatment (p <0.05). During the LVP test some side effects, possibly due to systemic vasoconstriction, were no ted such as abdominal pain, nausea and vomiting, and transient hyperte nsion. in conclusion, intranasal BDP at the dose of 400 or 800 mu g/da y during 4 weeks did not induce HPA axis suppression. The LVP test is efficient to demonstrate HPA hypofunction or suppression and it produc ed only mild to moderate transient side effects. However, due to the s ide effects observed, a safer test such as urinary free cortisol (24 h ours), should be used in the investigation of the HPA axis.