Dexamethasone: answers

02 January 2025
Volume 7 · Issue 1

Abstract

The half-life of oral dexamethasone is 20 mg every 4 hours. What is the serum concentration after 20 hours?

  • 625 micrograms
  • Initial dosage of 20 mg. 20 hours divided by 4 hours = 5 half-life reductions
  • First half-life = 10 mg Second half-life = 5 mg Third half-life = 2.5 mg Fourth half-life = 1.25 mg Fifth half-life after 20 hours = 625 micrograms

The half-life of oral dexamethasone is 20 mg every 4 hours. What is the serum concentration after 20 hours?

A 10-month-old child, weight 9 kg, is diagnosed with mild croup and prescribed 150 micrograms/kg for one dose. What is the dose to be prescribed?

A 3-week-old child, weight 3 kg, is prescribed dexamethasone for suppression of an inflammatory disorder. An initial emergency dose of 300 micrograms/kg is required.

3a). What emergency dose should be prescribed?

3b). The emergency dose should be followed by a regular prescription of 80 micrograms/kg daily in two divided dosages. What maintenance dose should be prescribed?

A 5-year-old child, weight 18 kg, requires dexamethasone IV infusion of 120 micrograms/kg (maximum 20 mg per day). What is the dose to be prescribed?

A 2-year-old child, weight 12 kg, requires dexamethasone physiological replacement of 250–500 micrograms/m2 every 12 hours. Body surface area for 12 kg is 0.56 (NICE, 2024).

5a). What is the minimum dose required?

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