Vitamin d

1. Vitamin d Ajith.A

2. Fat soluble , maintanence of plasma calcium and phosphate level , thermostabile ISOFORMS Vitamin D1 Vitamin D2 ( calciferol ) Vitamin D3 ( cholecalciferol )

3. Activation 7-Dehydro cholesterol Ergosterol UV light Calciferol Cholecalciferol 25- Hydroxy cholecalciferol 25-Hydroxy calciferol Liver microsomes Calcitriol 1,25- Di Hydroxy calciferol Kidney Mitochondria Active forms

4. ACTIONS Calcitriol enhances absorption of calcium and phosphate from intestine. It enhances resorption of calcium & phosphate from bone Calcitriol enhances tubular reabsorption of calcium & phosphate in kidney

5. RDA 5µgm ( 200 IU) or 400 IU/day if there is no synthesis in body PREPARATIONS CALCIFEROL as solution in oil, filled in gelatin capsules 25,000 and 50,000 IU caps. CHOLECALCIFEROL as granules for oral ingestion and oily solution for i.m injection

6. CALCITRIOL 0.25 – 1 µgm orally daily or on alternate days 0.5 – 1 µgm I.v on alternate days ALFACALCIDOL It is 1 α – OHD3, a prodrug that is rapidly hydroxylated in the liver to calcitriol 1-2µgm/day in adults for children<20 kg 0.5 µgm/ day DIHYDROTACHYSTEROL synthetic vit D2 analogue 0.25 – 0.5 mg/ day

7. PHARMACOKINETICS Absorption Intestine in presence of bile salts Storage Adipose tissues t1/2 1-18 Days Excretion Bile

8. V it d d eficiency Inadequate absorption Plasma calcium & phosphate Secretion of PTH Calcium mobilization from bone to restore plasma Ca 2+ Mineralization of bone fails in newly laid area & becomes soft Rickets in children Oestomalacia in adults

9. USES Prophylaxis (400 IU/ day) Treatment of nutritional Vit D deficiency ( 3000-4000 IU/day) or ( 3,00,000 – 6,00,000 IU) orally or i.m once in 2-6 mnths Metabolic rickets A.) Vit D resistant ricket administration of phosphate with calcitriol or alfacalcidol

10. B.) Vit D dependent rickets administration of calcitriol or alfacalcidol C.) Renal rickets alfacalcidol or calcitriol Senile or post menopausal osteoporosis Vit D3 + Calcium Hypoparathyroidism Dihydrotachysterol is given Fanconi syndrome

11. HYPERVITAMINOSIS > 50,000 IU/ day Excess ingestion of vit D leads to Hypercalcemia Weakness Fatigue Vomiting

12. Diarrhoea sluggishness Polyuria Albuminuria Renal stones hypertension

13. Thank you