Decadron
Decadron
Generic Name
Decadron
Brand Names
for dexamethasone, a potent synthetic glucocorticoid with anti‑inflammatory, immunosuppressive, and anti‑emetic properties.
Mechanism
- Glucocorticoid receptor agonist → Forms a complex that translocates to the nucleus.
- Transactivates anti‑inflammatory genes (e.g., lipocortin‑1, IL‑10).
- Transrepresses pro‑inflammatory genes (e.g., IL‑1β, IL‑6, COX‑2, TNF‑α) by inhibiting NF‑κB and AP‑1.
- Inhibits phospholipase A2, reducing arachidonic acid release and downstream eicosanoid production.
- Suppresses leukocyte trafficking and decreases capillary permeability.
Result: potent reduction of edema, inflammation, and immune responses.
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Pharmacokinetics
| Parameter | Typical Value (IV/PO) |
| Absorption | PO: ~95% bioavailability; IV: 100% |
| Distribution | Vd ≈ 0.6–0.7 L/kg; highly protein‑bound (~95%) |
| Metabolism | Microsomal oxidation (CYP3A4) → inactive metabolites |
| Elimination | Renal excretion of metabolites; half‑life 3–4 h (IV); 3–5 h (PO) |
| Special Populations | ↓ clearance in hepatic impairment; use caution in renal disease |
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Indications
- Anti‑inflammatory / immunosuppressive:
- Asthma exacerbations, COPD flare‑ups, rheumatic arthritis, systemic lupus erythematosus.
- Neuro‑oncology: reduce cerebral edema in brain tumors or metastases.
- Oncology: adjunct to chemotherapy (e.g., in lymphoma) and as anti‑emetic prophylaxis.
- Dermatology: acute severe dermatitis, atopic dermatitis flares.
- Others: hypoadrenalism, endocrine disorders, adrenal insufficiency, acute pancreatitis (controversial), and prophylaxis for high‑altitude sickness (in some settings).
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Contraindications
- Absolute: hypersensitivity to dexamethasone; active systemic fungal infections.
- Relative: uncontrolled infections, chronic alcoholism, poorly controlled diabetes, peptic ulcer disease, uncontrolled hypertension.
- Warnings:
- Hyperglycemia, hypertension, fluid retention, adrenal suppression, mood changes.
- Risk of Cushingoid features with prolonged use.
- Immunosuppression increasing infection risk.
- Potential for steroid‑related ocular complications (cataracts, glaucoma).
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Dosing
| Scenario | Dose | Route | Frequency | Notes |
| Adult anti‑inflammatory | 0.75–2 mg PO or IV q24 h | PO or IV | 7–14 days | Taper over 2–3 weeks to prevent adrenal crisis |
| Cerebral edema (acute) | 8 mg IV ↑ | IV | 1 day | Follow with 4 mg BID → 2 mg BID → 1 mg BID taper |
| Oncology (pre‑chem) | 4–8 mg IV 30 min before chemo | IV | Single dose | Timing per chemo regimen |
| Pediatric dosing (neurosurgery) | 0.2 mg/kg IV (max 8 mg) q12–24 h | IV | 2–4 days | Weight‑based; monitor for infection |
| Pediatric anti‑emetic prophylaxis | 0.1–0.5 mg/kg PO (max 10 mg) | PO | 1–3 days | Adjust per regimen |
Titration: For chronic conditions, begin at the lowest effective dose and adjust every 1–2 weeks.
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Adverse Effects
Common (≥10 %):
• Weight gain, fluid retention, increased appetite
• Hyperglycemia, insomnia, mood lability
• Acne, hirsutism, facial flushing
• GI upset, mild gastric irritation
Serious (≤1 % or higher with prolonged use):
• Osteoporosis, spontaneous fractures
• Severe immunosuppression → opportunistic infections
• Steroid‑induced psychosis, agitation
• Adrenal insufficiency on abrupt withdrawal
• Cataract, glaucoma, peptic ulcer disease
• Viral zoster reactivation
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Monitoring
| Parameter | Frequency | Rationale |
| Blood glucose | Baseline, then weekly (diabetics) | Steroid‑induced hyperglycemia |
| Blood pressure | Baseline, then daily in hospitalized pts | Hypertension risk |
| Weight | Baseline, then weekly | Fluid retention |
| Bone density (long‑term therapy) | Baseline, then annually | Osteoporosis prevention |
| Mental status | Baseline, every visit | Psychosis, mood changes |
| Liver function tests | Baseline, monthly (long‑term) | Hepatic metabolism impact |
| Kidney function | Baseline, periodically | Renal excretion of metabolites |
| Adrenal axis | Baseline, when tapering >1 month | Avoid adrenal crisis |
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Clinical Pearls
- Taper Early, Taper Gradually: Even short courses (>3 days) need a gradual taper to prevent adrenal insufficiency, especially when steroids >10 mg/day.
- Use the Lowest Effective Dose: Dexamethasone has a very long duration of action; 0.75 mg can be sufficient for many indications; higher doses increase side‑effect burden.
- Non‑oral Routes Avoid First‑Pass: IV or IM avoids extensive hepatic metabolism and ensures 100 % bioavailability – critical for acute indications (e.g., cerebral edema).
- Potent Anti‑emetic: 4 mg IV 30 min before cisplatin or carboplatin markedly reduces nausea/vomiting; consider synergy with ondansetron.
- Drug Interactions: Co‑administering with CYP3A4 inducers (e.g., rifampin, phenytoin) may decrease dexamethasone exposure; inducers of CYP3A4 can enhance metabolism, requiring dose escalation.
- Glycemic Control: For diabetics, insulin regimen may need adjustment 12–48 h after IV dexamethasone due to peak glucose rise at ~2–12 h post‑dose.
- Stress‑dose Steroids: In surgical patients on chronic steroids, give a “stress dose” (e.g., 10 mg IV) peri‑operatively to mimic physiologic cortisol.
- Ocular Screening: Annual eye exams for patients on >3 months of therapy; consider prophylactic topical steroids if cataract or glaucoma risk becomes significant.
- Patient Education: Advise patients to *not* abruptly stop therapy; provide a written taper schedule to avoid adrenal crisis.
- Pregnancy Category: Dexamethasone is category C; use only if benefits outweigh risks. Avoid during first trimester unless absolutely necessary.
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• *For deeper dives into dexamethasone’s pharmacogenomics, novel indications, or case studies, refer to the latest literature in *Pharmacotherapy* and *The New England Journal of Medicine*.