Dexamethasone
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Contents |
Introduction
- Tradenames: Decadron, Maxidex, AK-Dex.
Indications
- inflammation
- autoimmune disease
- allergic disorders
- hematologic disorders
- neoplastic disorders
- antiemetic
- bone metastasis: reduces bone pain
- neuropathic pain
- cerebral edema
- septic shock
- diagnostic agent for Cushing's disease
- ophthalmic inflammation
- macular edema (Ozurdex)
- dermatoses (topical)
- prophylaxis for post-operative nausea & vomiting [6]
Dosage
- Systemic agent:
- anti-inflammatory:
- Load 10-20 mg IV, maintenance 4 mg every 6 hours
- pediatric meningitis: 0.15 mg/kg IV.
- tuberculous meningitis (4-6 weeks duration)
- 2 weeks IV (0.3 mg/kg per day for week 1, 0.2 mg/kg per day for week 2)
- 4 weeks oral (0.1 mg/kg per day for week 3, then 3 mg per day, decreasing by 1 mg each week)
- croup: 0.6 mg/kg IM.
- antiemetic: 10 mg IV prior to chemotherapy
- metastatic bone pain: 4 mg IB every 6 hours
- physiologic replacement therapy:
- 0.03-0.15 mg/kg/day
- 0.6-0.75 mg/m2/day
- divide every 6-12 hours
- low-dose dexamethasone suppression test:
- 1 mg at 11 PM
- serum cortisol at 8 AM
- Tabs: 0.25, 0.5, 0.75, 1.0, 1.5, 2, 4, 6 mg.
- Elixir: 0.5 mg/5 mL.
- Injection: 8 & 16 mg/mL (dexamethasone acetate) (5 mL)
- Vitreal implant for treatment of macular edema: Ozurdex
- Topical agent: 0.1% cream BID. Soluble in EtOH, insoluble in H2O. Nasal preparation: 2 sprays BID/ TID.
- Ophthalmic: ointment: (0.1%) BID- QID solution: 1 drop every 1-6 hours (1%)
Pharmacokinetics
- oral bioavailability is 78 +/- 14%
- protein binding: 68%
- metabolized in liver
- 3% excreted in the urine
- elimination 1/2life is 3.0 +/- 0.8 hours
- elimination via liver
- 1/2life = 3.0 hours
- protein binding = 68 %
Adverse-effects
- common (> 10%) [5]
- less common (1-10%) [5]
- uncommon (< 1%) [5]
- seizures, mood swings, headache, skin atrophy, bruising, hyperpigmentation, acne, amenorrhea, Na+ & H20 retention, Cushing's syndrome, hyperglycemia, suppression of bone growth, abdominal distention, ulcerative esophagitis, pancreatitis, muscle wasting, hypersensitivity reactions, delirium, hallucinations, euphoria
- short term use [4]
- fluid & electrolyte disturbances
- hyperglycemia
- poor wound healing
- GI disturbances
- immune suppression
- long term use [4]
- osteoporosis
- bone fractures
- pituitary & adrenal insufficiency
- Cushing's syndrome
- adrenal insufficiency may manifest with rapid withdrawal
- ophthalmic agent [4]
- irritation
- increased intraocular pressure
- cataracts
- uncommon (< 1%) [5]
- burning, itching, irritation, dryness, folliculitis, hypertrichosis, acne, hypopigmentation, perioral dermatitis, allergic contact dermatitis, skin maceration, secondary infection, skin atrophy, striae, miliaria
- burning, itching, irritation, dryness, folliculitis, hypertrichosis, acne, hypopigmentation, perioral dermatitis, allergic contact dermatitis, skin maceration, secondary infection, skin atrophy, striae, miliaria
Drug-interactions
- aminoglutethimide
- anticholinesterases
- barbiturates
- carbamazepine
- phenytoin
- rifampin
- live vaccines
- dexamethasone induces cyt P450 3A4
- may diminish levels of drugs metabolized by cyt P450 3A4
- may diminish levels of drugs metabolized by cyt P450 3A4
Mechanism-of-action
- a potent, long-acting synthetic glucocorticoid
- minimal mineralocorticoid activity
- reduces bone pain & neuropathic pain
- reduces vasogenit edema
- inhibits production of prostaglandins
- inhibits formation of vascular endothelial growth factor
More General Terms
- pregnenedione
- 11 hydroxycorticosteroid
- 17 hydroxycorticosteroid
- glucocorticoid
- neurologic agent
- antipruritic agent
Additional Terms
- cytochrome P450 3A4 (cytochrome P450 C3, nifedipine oxidase, P450-PCN1, NF-25, CYP3A4)
- dexamethasone suppression test
Internet Database
PubChem: 5743
PubChem: 3003
PubChem: 451600
References
- Merck Index 11th ed #8116
- Research Biochemicals International 1993-94 catalog
- The Pharmacological Basis of Therapeutics, 9th ed. Gilman et al, eds. Permagon Press/McGraw Hill, 1996
- Drug Information & Medication Formulary, Veterans Affairs, Central California Health Care System, 1st ed., Ravnan et al eds, 1998
- Kaiser Permanente Northern California Regional Drug Formulary, 1998
- Journal Watch 24(14):113, 2004 Apfel CC, Korttila K, Abdalla M, Kerger H, Turan A, Vedder I, Zernak C, Danner K, Jokela R, Pocock SJ, Trenkler S, Kredel M, Biedler A, Sessler DI, Roewer N; IMPACT Investigators. A factorial trial of six interventions for the prevention of postoperative nausea and vomiting. N Engl J Med. 2004 Jun 10;350(24):2441-51. PMID: [1]
