DEXAMETHASONE SODIUM PHOSPHATE PRESERVATIVE FREE
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.
Dexamethasone sodium phosphate is a corticosteroid with potent anti-inflammatory and immunosuppressant properties. It binds to the glucocorticoid receptor, leading to modulation of gene expression and suppression of pro-inflammatory cytokines, inhibition of phospholipase A2, and reduction of inflammatory mediators like prostaglandins and leukotrienes.
| Metabolism | Primarily metabolized in the liver via CYP3A4 to minor metabolites; dexamethasone itself is the active compound. The phosphate ester is rapidly hydrolyzed to dexamethasone after administration. |
| Excretion | Primarily renal (approximately 65-80% as free steroid and glucuronide conjugates); minor biliary/fecal elimination (10-15%). |
| Half-life | Terminal elimination half-life is 3-4 hours in adults; clinical context: biological effects persist >24 hours due to prolonged receptor binding. |
| Protein binding | Approximately 70-77%, primarily to albumin and corticosteroid-binding globulin (CBG). |
| Volume of Distribution | Volume of distribution: 0.8-1.0 L/kg; wide distribution indicates extensive tissue penetration, including CSF. |
| Bioavailability | Bioavailability: Oral (not applicable as parenteral only); intramuscular: ~80-100%; intra-articular: limited systemic absorption, essentially local. |
| Onset of Action | Intravenous: 1-2 hours; intramuscular: 1-2 hours; intra-articular: 12-24 hours; ophthalmic: minutes to hours (variable). |
| Duration of Action | Duration: 36-54 hours (anti-inflammatory); ophthalmic: 4-6 hours (tear concentration); intra-articular: 1-3 weeks. |
| Molecular Weight | 516.41 |
0.5-24 mg/day IV or IM in divided doses every 6-12 hours; acute conditions: 4-20 mg IV initially, then 2-4 mg every 4-6 hours.
| Dosage form | INJECTABLE |
| Renal impairment | No dose adjustment required for GFR >=15 mL/min; insufficient data for GFR <15 mL/min, use with caution. |
| Liver impairment | Child-Pugh A: no adjustment; Child-Pugh B: consider 50% dose reduction; Child-Pugh C: use with caution, titrate to effect. |
| Pediatric use | 0.024-0.34 mg/kg/day IV or IM in divided doses every 6-12 hours; max 12 mg/day; acute conditions: 0.1-0.5 mg/kg/dose every 12-24 hours. |
| Geriatric use | Use lowest effective dose; monitor for hyperglycemia, fluid retention, and osteoporosis; reduced starting dose may be needed due to decreased renal and hepatic function. |
| 1st trimester | Corticosteroids are associated with cleft palate in animal studies; human data limited but risk cannot be excluded. Use only if clearly needed. |
| 2nd trimester | May be used for fetal lung maturity (betamethasone preferred); consider risk of maternal glucose intolerance and fetal growth restriction. |
| 3rd trimester | Prolonged use may cause fetal adrenal suppression; short courses for fetal lung maturity are accepted. |
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 | Dexamethasone crosses the placenta; placental metabolism reduces fetal exposure compared to betamethasone, but significant transfer occurs. |
■ FDA Black Box Warning
None explicitly stated for dexamethasone sodium phosphate preservative-free, but corticosteroids in general carry warnings for increased risk of infections and adrenal suppression.
| Common Effects | immunosuppression |
| Serious Effects |
Systemic fungal infectionHypersensitivity to dexamethasone or any componentAdministration of live or live-attenuated vaccines in patients receiving immunosuppressive doses
| Precautions | May cause immunosuppression and increase susceptibility to infections; adrenal suppression with prolonged use; corticosteroid-induced myopathy; osteoporosis with long-term use; growth suppression in children; glaucoma and cataracts with ophthalmic use; fluid and electrolyte disturbances; gastrointestinal perforation risk; psychiatric disturbances; and withdrawal syndrome upon abrupt discontinuation. |
| Food/Dietary |
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| Breastfeeding |
| Dexamethasone enters breast milk in low amounts. Typically compatible with breastfeeding, but monitor infant for potential adrenal suppression if high maternal doses are prolonged. |
| Lactation Rating | L2 (Safer) |
| Teratogenic Risk | First trimester: Increased risk of oral clefts (1-3 per 1000 births), dose-dependent. Second/third trimester: Long-term use associated with fetal growth restriction, adrenal suppression, and possible neurodevelopmental effects. |
| Fetal Monitoring | Monitor maternal blood glucose, blood pressure, and signs of infection. Fetal ultrasound for growth and amniotic fluid volume if long-term use. Newborn: assess for adrenal insufficiency if maternal use in late pregnancy. |
| Fertility Effects | May suppress ovulation and menstrual cycles at high doses; reversible upon discontinuation. No evidence of permanent fertility impairment. |
| Avoid excessive salt intake as this drug promotes sodium and fluid retention. May decrease potassium levels; consider potassium-rich foods under medical advice. Grapefruit juice may inhibit CYP3A4, potentially increasing dexamethasone levels; limit consumption. |
| Clinical Pearls | Preservative-free formulation prevents toxicity from benzyl alcohol (associated with gasping syndrome in neonates). Useful for intraocular, epidural, or intravenous use in patients with sulfite sensitivity. Taper dose to avoid adrenal insufficiency after prolonged therapy. Onset of action is rapid (minutes IV). Monitor for hyperglycemia, especially in diabetic patients. |
| Patient Advice | Do not abruptly stop this medication; follow your doctor's instructions for tapering the dose to avoid withdrawal symptoms. · Report any signs of infection (fever, sore throat) as this drug can mask symptoms and increase infection risk. · This medication may cause increased blood sugar; monitor if you have diabetes. · Avoid live vaccines while on this medication. · Inform all healthcare providers that you are taking this medication before any surgery or emergency treatment. |