Oral Dexamethasone Dosing for a 16-Year-Old
The typical oral dose of dexamethasone for a 16-year-old is 0.3 mg/kg/day, with a maximum of 8-12 mg depending on the indication. 1
General Dosing Principles
- Dexamethasone has equivalent dosing when converting from IV to PO administration (1:1 ratio), meaning the same dose can be used whether administering orally or intravenously 2
- Dosing requirements are variable and must be individualized based on the disease being treated and the patient's response 1
- For adolescents with obesity, pharmacokinetic studies suggest that weight-based dosing at 0.5-1 mg/kg provides appropriate exposure 3
Indication-Specific Dosing
Antiemetic Use (Chemotherapy-Induced Nausea/Vomiting)
- For high emetic risk chemotherapy: 12 mg oral dexamethasone on day 1, followed by 8 mg on days 2-3 or 2-4 4
- For moderate emetic risk chemotherapy: 8 mg oral dexamethasone on day 1, followed by 8 mg on days 2-3 4
- For low emetic risk chemotherapy: Single 8 mg oral dose 4
Acute Allergic Disorders
- Initial dose: 4-8 mg intramuscularly on day 1, followed by oral taper 1
- Oral taper example: 3 mg twice daily for days 2-3, then 1.5 mg twice daily on day 4, then 0.75 mg daily on days 5-6 1
Asthma Exacerbations
- Single dose of 0.3 mg/kg oral dexamethasone has been shown to be non-inferior to a 3-day course of prednisolone (1 mg/kg/day) for acute asthma exacerbations 5
- This single-dose approach may improve compliance compared to multi-day regimens 5
Multiple Myeloma Regimens
- When used in combination therapy for multiple myeloma, dexamethasone is typically dosed at 40 mg orally on specific days of the treatment cycle 4
- For example, in the VRd regimen (bortezomib, lenalidomide, dexamethasone): 40 mg on days 1,8,15,22 of a 28-day cycle 4
Important Considerations
- Dexamethasone is 80-100 times more potent than hydrocortisone in suppressing adrenal function, so careful dosing is essential 6
- Due to its high potency, the potential for overtreatment remains high with dexamethasone, requiring close monitoring 6
- For adolescents receiving long-term therapy, lower doses (0.15-0.3 mg/m²/day) may be appropriate to minimize growth effects 6
- If the drug is to be stopped after more than a few days of treatment, it usually should be withdrawn gradually to prevent adrenal insufficiency 1
Common Pitfalls to Avoid
- Do not confuse dexamethasone with other corticosteroids that may have different oral-to-IV conversion ratios 2
- Do not adjust the dose when converting between oral and IV formulations of dexamethasone 2
- Avoid prolonged use without monitoring for adverse effects such as hyperglycemia, immunosuppression, and growth inhibition 6, 7