betamethasone
Brand: Celestone Soluspan
Prototype: prednisone
Drug Class: corticosteroid
Drug Family: corticosteroid
Subclass: long-acting synthetic glucocorticoid
Organ Systems: endocrinerespiratory
Mechanism of Action
Long-acting synthetic glucocorticoid with ~25 times the anti-inflammatory potency of hydrocortisone and essentially no mineralocorticoid activity. Activates GR to suppress inflammatory gene transcription, stimulates fetal lung maturation in utero by inducing surfactant synthesis in type II pneumocytes.
glucocorticoid receptor (GR)
Indications
- antenatal fetal lung maturation (prematurity 24–34 weeks gestation)
- inflammatory and autoimmune conditions
- cerebral edema
- intra-articular inflammation
Contraindications
- systemic fungal infections
- hypersensitivity
Adverse Effects
Common
- transient fetal heart rate changes
- hyperglycemia
- maternal insomnia
Serious
- fetal neurodevelopmental effects with repeated courses
- adrenal suppression
- Cushing's syndrome (long-term)
Pharmacokinetics (ADME)
| Absorption | IM; betamethasone acetate (slow release) + betamethasone phosphate (rapid release) in Celestone Soluspan |
| Distribution | widely distributed; crosses placenta readily (unlike prednisone, which is inactivated by placental enzymes) |
| Metabolism | hepatic |
| Excretion | renal |
| Half-life | 35–54 hours (biologic) |
| Onset | hours to 24 hours (for fetal lung effect) |
| Peak | 1–2 hours |
| Duration | 24–72 hours |
| Protein Binding | 64% |
| Vd | moderate |
Drug Interactions
| Drug / Agent | Mechanism | Severity |
|---|---|---|
| NSAIDs | additive GI effects | moderate |
Nursing Considerations
- For fetal lung maturation: administer two doses of 12 mg IM 24 hours apart; delivery is expected within 1 week of treatment.
- Monitor maternal blood glucose closely; betamethasone transiently raises glucose for 24–48 hours, requiring insulin adjustment in diabetic mothers.
- Monitor fetal heart rate for expected transient changes after administration.
- Betamethasone is preferred over dexamethasone for antenatal use per ACOG guidelines because it does not contain preservatives that may cause fetal harm.
Clinical Pearls
- Unlike prednisone (which is converted to inactive prednisolone by placental 11β-HSD2), betamethasone and dexamethasone are not inactivated by the placenta, allowing direct fetal exposure — precisely why betamethasone is used for antenatal lung maturation.
- A single course of antenatal betamethasone remains one of the most evidence-based interventions in perinatology, reducing neonatal RDS, IVH, NEC, and mortality in preterm infants.
Safety Profile
Pregnancy avoid
Lactation generally-safe
Renal Adjustment Not required
Hepatic Adjustment Not required
TDM Not required
Concordance Terms
Cross-referenced clinical concepts — click any term to see all content where it appears.