Betamethasone
Betamethasone is a very potent, long-acting synthetic glucocorticoid (roughly 25-30 times cortisol potency, similar to dexamethasone) with negligible mineralocorticoid activity. It is used topically at high potency, as a combined fast/slow depot injection (Celestone/Diprospan) for joints, and antenatally to accelerate fetal lung maturity. Same corticosteroid trade-offs: strong anti-inflammatory action, but catabolic and HPA-suppressive.
01 Overview
Betamethasone is the beta-epimer of dexamethasone and shares its high potency and long duration. The injectable combines betamethasone sodium phosphate (fast-acting) with betamethasone acetate (depot), giving both rapid and sustained effect — a popular joint and soft-tissue injection. Antenatal betamethasone is a well-established intervention to reduce neonatal respiratory distress in preterm birth.
As with other potent long-acting glucocorticoids, systemic exposure strongly suppresses the HPA axis and, over time, is catabolic and immunosuppressive. Injectable and systemic betamethasone are WADA-prohibited in-competition.
02 Mechanism
Potent, long-acting glucocorticoid receptor agonist with minimal mineralocorticoid activity; suppresses inflammatory transcription broadly.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Topical (potent) | 0.025–0.1 % | Transdermal | High-potency topical for inflammatory skin disease. |
| Systemic | 0.25–7.2 mg/day | Oral | Range by indication; potent per milligram. |
| Depot injection | 6–12 mg | IM | Combined fast/depot ester for joint or systemic use. |
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Very potent anti-inflammatory actionStrong, durable inflammation control systemically and topically. | ~25-30x cortisol | Clinical | |
| Fetal lung maturation (antenatal)Antenatal course reduces respiratory distress in preterm neonates. | reduced neonatal RDS | Clinical |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| HPA axis suppressionLong duration produces strong, durable adrenal suppression. | Severe | Universal with sustained use | Clinical | |
| Skin atrophy (topical high potency)Thinning skin, striae and telangiectasia with prolonged potent topical use. | Moderate | Common with prolonged topical use | Clinical | |
| HyperglycaemiaRaised blood glucose from potent glucocorticoid action. | Moderate | Common | Clinical |