Dexamethasone: A Synthetic Corticosteroid Medication
Dexamethasone is a synthetic glucocorticoid (corticosteroid) medication with potent anti-inflammatory and immunosuppressive properties, approximately 25-30 times more potent than hydrocortisone and with a longer duration of action (2-3 days). 1, 2, 3
Chemical and Pharmacological Properties
Dexamethasone is chemically designated as 9-fluoro-11β,17-dihydroxy-16α-methyl-21-(phosphonooxy)pregna-1,4-diene-3,20-dione disodium salt when formulated as dexamethasone sodium phosphate 1
It is a long-acting systemic corticosteroid with potency approximately 25 times greater than short-acting products like hydrocortisone 2
Dexamethasone has high glucocorticoid activity but minimal mineralocorticoid activity, distinguishing it from other corticosteroids 4
The medication is freely soluble in water and exceedingly hygroscopic in its sodium phosphate form 1
Clinical Applications in Neurosurgery
Dexamethasone is the preferred corticosteroid for most neurosurgical indications, particularly for cerebral edema management 4
For mild symptoms related to mass effect: 4-8 mg/day is recommended 4
For moderate to severe symptoms related to mass effect: 16 mg/day or higher doses are recommended 4
Dexamethasone is the first-line corticosteroid for managing cerebral edema due to its high potency and minimal mineralocorticoid activity 4
Use in Other Medical Conditions
Dexamethasone is commonly administered as an antiemetic, with doses of 4-5 mg showing similar clinical effects to 8-10 mg for prevention of postoperative nausea and vomiting 5
The medication is used in combination with other agents for multiple myeloma treatment (venetoclax/dexamethasone, pomalidomide/dexamethasone) 6
Dexamethasone is employed in sudden hearing loss treatment, typically at 10 mg/day for 5 days followed by tapering 6
It is used in dermatological conditions such as pemphigus vulgaris, administered as 100 mg intravenously on three consecutive days monthly in pulse therapy protocols 6
Formulation and Administration
Dexamethasone sodium phosphate injection is supplied as a sterile solution at 4 mg/mL (equivalent to 4.4 mg dexamethasone sodium phosphate) 1
The medication can be administered via intravenous, intramuscular, intra-articular, intralesional, and soft tissue routes 1
Standard immediate-release dexamethasone tablets can be crushed when necessary for patients with dysphagia 7
Oral and intravenous routes are considered equivalent alternatives with similar bioavailability 7
Immunological Effects
Dexamethasone causes dose-dependent changes in immune cell populations, including increased neutrophil counts and decreased monocytes, lymphocytes, basophils, and eosinophils at 4 hours post-administration 8
The medication has immunosuppressive effects that inhibit T cell activation and block B cell antibody production 3
Dexamethasone blocks macrophages from clearing secondary infections, which is a critical consideration in infectious disease management 3
Important Clinical Caveats
Dexamethasone alone is inadequate for patients with primary adrenal insufficiency due to lack of mineralocorticoid activity; hydrocortisone is preferred in these cases 4
Abrupt discontinuation after prolonged use can lead to adrenal insufficiency; tapering is essential 4
The medication may cause transient hyperglycemia in a dose-dependent manner, requiring glucose monitoring in diabetic patients 5
Dexamethasone was FDA-approved in 1958 as a broad-spectrum immunosuppressor with duration of action of 2-3 days 3