Vitamin D2
Ergocalciferol
Brand names: various
Adult dose
Dose: Deficiency: 50,000 units PO weekly for 6–10 weeks (loading); maintenance 800–2,000 units OD
Route: Oral
Frequency: Weekly (loading) / OD (maintenance)
Clinical pearls
- NICE NG121 osteoporosis / fragility fracture: cholecalciferol (D3) generally preferred over D2 due to longer half-life
- UK National Osteoporosis Society / Royal Osteoporosis Society guidance
- Vegan-suitable form of vitamin D
Contraindications
- Hypercalcaemia
- Hypervitaminosis D
- Severe renal failure
- Metastatic calcification
Side effects
- Hypercalcaemia (over-dose)
- Hypercalciuria
- Renal stones
- Constipation
Interactions
- Thiazides (hypercalcaemia)
- Digoxin (with hypercalcaemia)
- Calcium supplements
- Magnesium-containing antacids
Monitoring
- 25(OH)D level after 8–12 weeks loading
- Calcium
- Renal function
Reference: BNF; NICE NG121; Royal Osteoporosis Society; https://bnf.nice.org.uk/drugs/ergocalciferol/. Verify against your local formulary and the latest BNF before prescribing.
Related
Curated clinical cross-links plus same-class fallbacks.
Pathways
- Sepsis Screening and Sepsis Six · UK Sepsis Trust; NICE NG51; Surviving Sepsis Campaign 2021
- Unintentional Weight Loss Workup · NICE NG12; BSG
- Chronic Fatigue Workup · NICE NG206; BMJ Best Practice
- Lymphadenopathy Workup · NICE NG12; BMJ Best Practice
- Pre-op Medical Clearance · NICE NG45; ESC 2022
- Secondary Hypertension Workup · NICE NG136; ESH 2023