Dexamethasone suppression tests are used to assess the status of the hypothalamic-pituitary-adrenal (HPA) axis and for the differential diagnosis of adrenal hyperfunction. The low-dose dexamethasone suppression tests are used to assess nonsuppressible cortisol production by adrenal incidentalomas and to differentiate patients with Cushing's syndrome of any cause from patients who do not have Cushing's syndrome. The high-dose dexamethasone suppression tests help to distinguish patients with Cushing's disease (Cushing's syndrome caused by pituitary hypersecretion of corticotropin [ACTH]) from most patients with the ectopic ACTH syndrome (Cushing's syndrome caused by nonpituitary ACTH-secreting tumors).
The 4 mg/mL injection strength may be used for intralesional and soft tissue administration. Doses range from mg to 4 mg injected as a single dose at the appropriate site. For soft tissue and bursal injections a dose of 2 to 4 mg is recommended. Ganglia require a dose of 1 to 2 mg. A dose of to 1 mg is used for injection into tendon sheaths. Usually employed when condition to be treated is limited to 1 or 2 sites. Dosage dependent upon degree of inflammation, size, disease state, and location of affected area. Repeat doses may be given from once every 3 to 5 days to once every 2 to 3 weeks.