Ergocalciferol (Calciferol) 💊
📌 See also: Vitamin D Deficiency and Management
📖 About
Always check the BNF link here before prescribing.
- 💊 Ergocalciferol = Vitamin D₂ (plant-derived form of Vitamin D).
- 🔄 Requires hydroxylation in the liver and kidneys → active 1,25-dihydroxy Vitamin D.
⚡ Mechanism of Action
- ⬆️ Increases intestinal absorption of calcium and phosphate.
- 🦴 Promotes bone mineralisation and suppresses secondary hyperparathyroidism.
- 🌱 Plant source (ergosterol → ergocalciferol when UV-activated).
🩺 Indications
- Vitamin D deficiency (mild, moderate, or severe).
- Hypoparathyroidism (long-term management).
💊 Dosing (check BNF/datasheet)
| Indication |
Dose / Details |
| 🍽️ Dietary supplement |
10 micrograms (400 units) daily |
| 🦴 Vitamin D deficiency |
20 micrograms (800 units) daily |
| ⚠️ Severe deficiency |
1 mg (40,000 units) daily |
| 🧬 Hypoparathyroidism |
2.5 mg (100,000 units) daily (specialist use, close monitoring required) |
| 👴 Elderly / high hypercalcaemia risk |
Reduce dose accordingly |
⚠️ Interactions
- See BNF – interactions with enzyme inducers (e.g. phenytoin, carbamazepine), digoxin (↑ toxicity with hypercalcaemia), and other Vitamin D analogues.
⚠️ Cautions
- Hypercalcaemia (monitor calcium & U&E regularly).
- Risk of metastatic calcification with prolonged high doses.
🚫 Contraindications
- See BNF – avoid in persistent hypercalcaemia, severe renal impairment with uncontrolled phosphate, or hypersensitivity.
💥 Side Effects
- ⬆️ Hypercalcaemia (nausea, vomiting, confusion, arrhythmias).
- 🪨 Nephrocalcinosis, renal stones.
- 🌡️ Rash, urticaria (rare).
📑 References
