DEXONE 0.5
Clinical safety rating: caution
Comprehensive clinical and safety monograph for DEXONE 0.5 (DEXONE 0.5).
Dexamethasone is a glucocorticoid receptor agonist, binding to the glucocorticoid receptor (GR) and modulating gene expression through transactivation and transrepression. It inhibits phospholipase A2, reduces prostaglandin and leukotriene synthesis, suppresses cytokine production (IL-1, IL-2, IL-6, TNF-alpha), and decreases immune cell migration and activation.
| Metabolism | Primarily hepatic metabolism via CYP3A4; also metabolized by 11β-hydroxysteroid dehydrogenase (11β-HSD) to inactive metabolites. Elimination half-life is approximately 3-4 hours, but biologic half-life is longer (36-54 hours due to intracellular activity). |
| Excretion | Renal: 70-80% (mostly as 6β-hydroxydexamethasone); biliary/fecal: 10-15% |
| Half-life | 3.0-4.5 hours; prolonged in hepatic impairment (up to 6-8 hours) or concurrent CYP3A4 inhibitors |
| Protein binding | 77-84% (corticosteroid-binding globulin, albumin) |
| Volume of Distribution | 0.8-1.2 L/kg; indicates extensive tissue penetration, including CNS (0.3-0.6 L/kg in CSF) |
| Bioavailability | Oral: 60-80%; IM: 80-100% (formulation-dependent) |
| Onset of Action | Oral: 1-2 hours; IV: immediate (minutes); IM: 2-3 hours |
| Duration of Action | Oral/IV: 36-54 hours (single dose); IM: 24-36 hours; duration prolonged with high doses or continuous therapy |
0.5 mg orally once daily, with gradual taper to lowest effective dose
| Dosage form | TABLET |
| Renal impairment | No adjustment required for GFR >30 mL/min; avoid in GFR <30 mL/min due to increased risk of adverse effects |
| Liver impairment | Child-Pugh A: no adjustment; Child-Pugh B: reduce dose by 50%; Child-Pugh C: avoid use |
| Pediatric use | 0.02-0.3 mg/kg/day orally divided once daily or twice daily; maximum 0.5 mg/day |
| Geriatric use | Initiate at lowest dose (0.25 mg daily) and titrate cautiously due to increased risk of osteoporosis, hyperglycemia, and immunosuppression |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for DEXONE 0.5 (DEXONE 0.5).
| Breastfeeding | Dexamethasone enters breast milk; M/P ratio 0.19-0.25. Low levels unlikely to harm infant, but high maternal doses may cause neonatal adrenal suppression. Consider timing doses after nursing. |
| Teratogenic Risk | First trimester: Increased risk of orofacial clefts (odds ratio ~3.4). Second/third trimester: Fetal adrenal suppression, intrauterine growth restriction, oligohydramnios. Prolonged use: Premature birth, low birth weight. |
| Fetal Monitoring |
■ FDA Black Box Warning
No FDA black box warning specific to dexamethasone.
| Serious Effects |
["Hypersensitivity to dexamethasone or any component","Systemic fungal infections","Administration of live or live-attenuated vaccines (relative contraindication)","Idiopathic thrombocytopenic purpura (relative)"]
| Precautions | ["Increased risk of infections due to immunosuppression","Adrenal suppression and withdrawal syndrome with abrupt discontinuation","Osteoporosis with long-term use","Hyperglycemia and diabetes exacerbation","Gastrointestinal perforation or bleeding","Cushing's syndrome with chronic use","Ocular effects: glaucoma, cataracts, central serous chorioretinopathy","Psychiatric disturbances (e.g., euphoria, psychosis)","Growth suppression in children","Fluid and electrolyte disturbances (sodium retention, potassium loss)"] |
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| Maternal: Blood pressure, blood glucose, weight gain, signs of adrenal insufficiency. Fetal: Serial ultrasound for growth, amniotic fluid index, fetal heart rate monitoring. Newborn: Observe for adrenal suppression, hypoglycemia. |
| Fertility Effects | May suppress ovulation due to interference with gonadotropin release. Long-term use can disrupt menstrual cycles and reduce fertility, which is reversible upon discontinuation. |