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# IV Dexamethasone
## Overview
Dexamethasone is a long-acting, potent glucocorticoid with negligible mineralocorticoid activity. IV formulation is used for rapid anti-inflammatory and immunosuppressive effects.
## Primary Indications
- Cerebral edema (e.g., from brain tumors)
- Severe acute asthma exacerbations
- Croup (in pediatric patients)
- Adjunctive therapy in COVID-19 (hypoxia/inflammatory phase)
- Anaphylaxis (part of resuscitation protocol)
- Spinal cord compression (malignancy)
- Antiemetic (prevention/control of chemotherapy-induced nausea/vomiting)
- Autoimmune/inflammatory conditions when rapid glucocorticoid effect needed
## Adult Dosing
- **Cerebral edema**: 10 mg IV once, then 4–6 mg IV every 6 hours; taper as tolerated.
- **Severe asthma exacerbation**: 6–10 mg IV once (or 0.6 mg/kg); then 4–6 mg IV every 6 hours or switch to oral.
- **COVID-19 (hypoxia)**: 6 mg IV once daily for up to 10 days (or until discharge). Per WHO/NIH guidelines.
- **Anaphylaxis**: 8–20 mg IV once (after epinephrine).
- **Antiemetic (chemotherapy)**: 8–20 mg IV before chemotherapy, often with other antiemetics.
- **Spinal cord compression**: 10 mg IV loading, then 4–6 mg IV every 6 hours; taper.
*Maximum single IV dose: Typically 20 mg; higher doses (up to 40–100 mg) used in specific protocols (e.g., status asthmaticus, septic shock). Consult local protocol.*
## Pediatric Dosing
- **Croup (mild to moderate)**: 0.15–0.6 mg/kg IV once (max 10 mg). Oral often preferred if tolerated.
- **Severe asthma exacerbation**: 0.3–0.6 mg/kg IV once (max 16–20 mg); then 0.15–0.3 mg/kg IV every 6 hours or switch to oral prednisolone.
- **Cerebral edema (malignancy)**: 0.5–1 mg/kg IV once, then 0.25–0.5 mg/kg every 6 hours (max single dose 16 mg). Taper.
- **Anaphylaxis**: 0.6 mg/kg IV once (max 16 mg).
- **Antiemetic**: 0.1–0.2 mg/kg IV (max 8–16 mg) before chemotherapy.
*Doses are per institutional protocols; adjust based on severity and weight.*
## Dose Adjustments
- **Hepatic impairment**: No specific IV dose adjustment for dexamethasone; monitor for adverse effects.
- **Renal impairment**: No dose adjustment; negligible renal elimination.
- **Elderly**: Use lowest effective dose; monitor for hyperglycemia, delirium.
- **Pregnancy**: Generally considered safe (Category C); use only if clearly needed.
## Contraindications
- Hypersensitivity to dexamethasone or any excipient
- Systemic fungal infection (except when used adjunctively for inflammatory complications)
- Active untreated infections (except in specific protocols, e.g., COVID-19, bacterial meningitis with antibiotics)
- Live virus vaccines (avoid during high-dose therapy)
## Adverse Effects
- **Common**: Hyperglycemia, insomnia, mood changes, increased appetite, fluid retention, hypertension, dyspepsia.
- **Serious**: Adrenal suppression (with prolonged use), osteoporosis, avascular necrosis, peptic ulcer, pancreatitis, psychosis, increased infection risk, Cushing’s syndrome.
- **High-dose/pulse**: Cardiac arrhythmias, sudden death (rare).
## Key Drug Interactions
- **Anticoagulants (warfarin)**: May alter INR; monitor closely.
- **NSAIDs**: Increased risk of GI ulceration/bleeding.
- **Antidiabetics**: Reduced glycemic control; adjust doses.
- **CYP3A4 inducers (e.g., phenytoin, carbamazepine, rifampin)**: Decrease dexamethasone efficacy; may need higher dose.
- **CYP3A4 inhibitors (e.g., ketoconazole, ritonavir)**: Increase dexamethasone levels; monitor toxicity.
- **Vaccines**: Decreased antibody response; avoid live vaccines during immunosuppressive therapy.
## Monitoring
- Serum glucose (especially in diabetics)
- Blood pressure, weight, electrolytes (if prolonged use)
- Signs of infection (masked by steroid)
- Adrenal suppression if withdrawing after >2 weeks of therapy (taper gradually)
- Psychiatric status (mood, behavior)
## Clinical Pearls
- **Onset of action**: IV dexamethasone has rapid anti-inflammatory effects (hours); peak effect for cerebral edema within 12–24 hours.
- **Half-life**: Long (36–54 hours); allows once-daily or twice-daily dosing in many conditions.
- **Mineralocorticoid activity**: Negligible, so not for adrenal crisis (use hydrocortisone instead).
- **Reconstitution**: Most IV formulations require dilution; check product labeling. Administer over several minutes (push) or short infusion.
- **Taper**: Withdraw gradually after >2 weeks of therapy; abrupt cessation can cause adrenal insufficiency.
- **Dose rounding**: Typical IV doses are multiples of 4 mg (e.g., 4, 8, 12, 16, 20 mg).
*This information is educational and does not replace clinical judgment. Always verify current prescribing information, local protocols, and product labeling before administering.*
