DEXAMETHASONE ACETATE
Clinical safety rating: avoid
CYP3A4 inducers (eg phenytoin) may decrease efficacy and inhibitors may increase effects Can cause hyperglycemia and adrenal suppression with prolonged use.
Agonist at glucocorticoid receptors, modulating gene expression to suppress inflammation, immune response, and adrenal function.
| Metabolism | Primarily hepatic via CYP3A4. |
| Excretion | Renal (primarily as glucuronide and sulfate conjugates) and biliary/fecal (minor). Approximately 65-80% of a dose is excreted in urine within 24 hours as 20-beta-dihydrodexamethasone (inactive) and conjugated metabolites; about 10-15% appears in feces. Less than 5% is excreted unchanged. |
| Half-life | Terminal elimination half-life: 3-5 hours in adults; slightly prolonged in neonates (approximately 12-24 hours) and patients with hepatic impairment. Clinical context: Duration of HPA axis suppression may exceed the presence of measurable drug; single dose typically suppresses cortisol for 24-36 hours. |
| Protein binding | Approximately 77-84% bound, primarily to albumin and to a lesser extent to alpha-1-acid glycoprotein. |
| Volume of Distribution | Approximately 0.6-0.8 L/kg (adults). This reflects moderate tissue distribution; drug crosses placenta and enters breast milk. |
| Bioavailability | Oral: approximately 80-90% (first-pass metabolism minimal). Intramuscular: 100% (by definition). Subcutaneous: 100% (by definition). Topical/ophthalmic: variable, but systemic absorption is minimal (<1% for most topical formulations, except when applied to large areas or broken skin). |
| Onset of Action | Intravenous: 1-2 hours (effects on glucose metabolism, inflammation). Intramuscular: 2-3 hours. Oral: 1-2 hours. Topical/ophthalmic: minutes to hours depending on formulation. Note: Onset of anti-inflammatory effect may be delayed up to 24-48 hours for some indications. |
| Duration of Action | Duration of biologic activity (glucocorticoid effect) is 36-54 hours; clinical duration for anti-inflammatory/immunosuppressive effects ranges from 24 to 72 hours depending on dose and individual. HPA axis suppression lasts 2-3 days after a single dose, longer with repeated dosing. |
| Molecular Weight | 434.5 |
0.5-9 mg/day orally in divided doses every 6-12 hours; intravenously or intramuscularly as dexamethasone sodium phosphate; typical anti-inflammatory dose 0.75-9 mg/day. For cerebral edema: IV loading dose 10 mg, then 4 mg every 6 hours. For COVID-19: 6 mg IV or orally once daily for up to 10 days.
| Dosage form | INJECTABLE |
| Renal impairment | No dose adjustment required for renal impairment; not removed by hemodialysis. |
| Liver impairment | No specific Child-Pugh based guidelines; caution in severe hepatic impairment due to risk of fluid retention and increased glucocorticoid sensitivity. |
| Pediatric use | Anti-inflammatory: 0.08-0.3 mg/kg/day or 2.5-10 mg/m2/day orally in divided doses every 6-12 hours; cerebral edema: IV loading dose 0.5-1 mg/kg, then 0.1-0.5 mg/kg/day divided every 6 hours. |
| Geriatric use | Start at lower end of dosing range due to increased risk of osteoporosis, hyperglycemia, and fluid retention; monitor closely. |
| 1st trimester | Use only if clearly needed; associated with cleft palate (animal data) but limited human data; weigh risks vs benefits. |
| 2nd trimester | May suppress fetal adrenal function; monitor fetal growth with prolonged use; use lowest effective dose. |
| 3rd trimester | Fetal HPA axis suppression possible; neonatal hypoglycemia and adrenal insufficiency reported; avoid chronic use. |
Clinical note
CYP3A4 inducers (eg phenytoin) may decrease efficacy and inhibitors may increase effects Can cause hyperglycemia and adrenal suppression with prolonged use.
| FDA category | Positive |
| Placental transfer | Readily crosses placenta; metabolized in placenta to inactive 11-keto form, but active drug reaches fetal circulation; about 67% of maternal serum levels. |
■ FDA Black Box Warning
None.
| Common Effects | immunosuppression |
| Serious Effects |
Systemic fungal infectionHypersensitivity to dexamethasone or any componentIntrathecal administration (contraindicated)Live or live-attenuated vaccines (concurrent use)
| Precautions | Hypothalamic-pituitary-adrenal (HPA) axis suppression, Increased susceptibility to infections, Masking of infection signs, Gastrointestinal perforation risk, Osteoporosis with long-term use, Cushing's syndrome, Adrenal crisis upon withdrawal, Growth suppression in children, Ocular effects (cataracts, glaucoma), Ketoacidosis in diabetes, Increased intraocular pressure, Thrombotic events, Myopathy, Psychiatric disturbances, Vaccination risks with live vaccines, Kaposi sarcoma, Anaphylactic reactions |
| Food/Dietary |
Loading safety data…
| Breastfeeding |
| Enters breast milk in low concentrations; at maternal doses up to 20 mg/day, minimal risk to infant; avoid high-dose or prolonged therapy; monitor infant for adrenal suppression if mother on chronic therapy. |
| Lactation Rating | L2 (Safer) - low risk, but monitor infant |
| Teratogenic Risk | Pregnancy Category C. First trimester: Increased risk of cleft palate (2-3 fold). Second/third trimester: Fetal adrenal suppression, growth restriction, and altered brain development. Avoid unless maternal benefit outweighs risk. |
| Fetal Monitoring | Monitor fetal growth via ultrasound; assess for adrenal suppression in newborn (hypoglycemia, hypotension). Monitor maternal blood pressure, glucose levels, and signs of infection. |
| Fertility Effects | May inhibit ovulation and disrupt menstrual cycle due to hypothalamic-pituitary-adrenal axis suppression. Reversible upon dose reduction or discontinuation. |
| Avoid grapefruit and grapefruit juice as they may increase dexamethasone levels. Limit high-sodium foods to reduce fluid retention and hypertension. Avoid alcohol as it can increase the risk of gastrointestinal bleeding. There are no significant interactions with other foods; however, a balanced diet with adequate calcium and vitamin D is advisable due to increased risk of osteoporosis with long-term use. |
| Clinical Pearls | Dexamethasone acetate is a long-acting glucocorticoid used primarily for its anti-inflammatory and immunosuppressive effects. Due to its minimal mineralocorticoid activity, it is preferred for conditions requiring high-dose glucocorticoid therapy without significant sodium retention. For cerebral edema, use high-dose dexamethasone (10 mg IV followed by 4 mg every 6 hours) – it is the glucocorticoid of choice because of its long half-life and low mineralocorticoid effect. In COVID-19, dexamethasone 6 mg once daily for up to 10 days reduces mortality in patients requiring oxygen or mechanical ventilation. Avoid abrupt withdrawal after prolonged therapy (>2 weeks) to prevent adrenal insufficiency; taper gradually. Dexamethasone suppresses the HPA axis for longer than other glucocorticoids; thus, stress doses may be needed for up to one year after discontinuation. Intravitreal injection is used for macular edema; monitor for intraocular pressure elevation and cataract formation. |
| Patient Advice | Take exactly as prescribed; do not stop suddenly without consulting your doctor. · Do not receive live vaccines while on this medication. · Report any signs of infection (fever, sore throat) or unusual bleeding/bruising. · May cause increased appetite, weight gain, and fluid retention; monitor your weight. · Avoid prolonged sun exposure; use sunscreen as the drug can make you more sensitive to sunlight. · If you have diabetes, monitor blood glucose more frequently as this drug can increase blood sugar. · Inform your doctor if you are pregnant, breastfeeding, or planning to become pregnant. · Carry a medical alert card indicating you are taking corticosteroids, especially if on long-term therapy. · Do not take NSAIDs (like ibuprofen) without discussing with your doctor to avoid increased GI bleeding risk. |