Single dose dexamethasone suppression test in children: dose relationship to body size

We have performed an overnight single dose dexamethasone suppression test in 15 children at different dosages to determine the minimum dose required to suppress the 0800 h serum cortisol level. With a dexamethasone dose of 0.1 mg/m2 two of seven children showed suppression. When the dose was increased to 0.3 mg/m2 all of six patients showed suppression as did three given dexamethasone 0.5 mg/m2. We recommend that doses of dexamethasone should be calculated in terms of body surface area when assessing the hypothalamo-pituitary axis in children and that a dose of 0.3 mg/m2 should be used for suppression tests.