Betamethasone
Betapred
Betapred is a distinctive formulation: the soluble tablet allows a child with croup or a patient with an allergic reaction to receive a full steroid dose without an injection, and the long biological duration means a single dose suffices. Potency is approximately 25 times that of hydrocortisone and mineralocorticoid effect is absent, making it suitable in cerebral oedema and cord compression where sodium retention is undesirable. The effect is not immediate — it requires hours and never replaces adrenaline in anaphylaxis.
Betamethasone has no role in the acute treatment of anaphylaxis. Adrenaline 0,5 mg im is first-line; the steroid is given only thereafter and does not affect the initial reaction.
Dosing in adults
| Indication | Regimen | Comment |
|---|---|---|
| Croup in children | 0,25 mg/kg orally as a single dose, in practice 8–12 dissolved tablets (4–6 mg) | dissolved in 5–10 ml water, effect within 1–2 hours |
| Allergic condition or asthma in adults | 1,5 mg (3 tablets) daily for 2 days, then taper over 4–6 days | in severe reaction 4–8 mg as a single dose; children 3 mg under 6 years, 5 mg from 6 years |
| Cerebral oedema due to tumour or metastasis | 8–16 mg daily orally or iv, divided into 2 doses | do not give the last dose after 15:00 — sleep disturbance |
| Malignant spinal cord compression | 16 mg iv or orally immediately, then 8 mg × 2 and taper | treat on suspicion, do not wait for MRI |
| Antenatal lung maturation | 12 mg im, repeated after 24 hours | gestational week 23+0 to 33+6, effect maximal after 24–48 hours |
No dose adjustment — excretion is mainly extra-renal, only approximately 5 % is found in urine within 24 hours.
No established dose adjustment. Betamethasone is the active substance and requires no hepatic activation, but clearance may decrease in severe hepatic failure.
Croup and obstructive symptoms: 0,25 mg/kg as a single dose. Acute asthma: 3 mg below 10 kg, 4–5 mg above 10 kg. Allergic reaction: 3 mg below 6 years, 5 mg from 6 years.
Avoid betamethasone in adrenal insufficiency: it lacks mineralocorticoid effect and provides neither sodium retention nor a means of monitoring substitution clinically. Also avoid repeated courses in children with recurrent obstructive symptoms without reassessing the diagnosis — the long duration masks the fact that the background inhaled steroid treatment is insufficient.
Pharmacokinetics
- PEAK CONCENTRATION
- within 2 hours orally
- t½ (plasma)
- approximately 5 hours
- BIOLOGICAL t½
- more than 48 hours
- DURATION
- 36–72 hours
- EQUIVALENCE
- 0,6 mg = 5 mg prednisolone = 20 mg hydrocortisone
- MINERALOCORTICOID EFFECT
- Absent
- METABOLISM
- Hepatic, CYP3A4
- EXCRETION
- Mainly extra-renal, approximately 5 % renal