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. |
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 | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
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 |
| Breastfeeding | Enters breast milk in low amounts; M/P ratio approximately 0.3-0.5. Short-term use is generally considered compatible, but high doses or prolonged use should be avoided. Monitor infant for growth and adrenal suppression. |
| 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. |
■ 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 infections; known hypersensitivity to dexamethasone or any component; concurrent live or live-attenuated vaccines; lactation (relative caution); and in patients with idiopathic thrombocytopenic purpura (for intramuscular use).
| 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. |
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| 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. |