Comparative Pharmacology
Head-to-head clinical analysis: ERGOCALCIFEROL versus VITAMIN D.
Peer-Reviewed Evidence
Head-to-head clinical analysis: ERGOCALCIFEROL versus VITAMIN D.
ERGOCALCIFEROL vs VITAMIN D
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Ergocalciferol is a fat-soluble vitamin that increases intestinal absorption of calcium and phosphate. It binds to vitamin D receptors (VDR), which regulate gene expression of proteins involved in calcium homeostasis, including calbindin-D9k, calcium channels, and the calcium pump. It also promotes renal tubular reabsorption of calcium and phosphate and mobilizes calcium from bone.
Vitamin D (cholecalciferol) is a secosteroid that binds to the vitamin D receptor (VDR), which heterodimerizes with the retinoid X receptor (RXR) to regulate gene transcription. It enhances intestinal calcium and phosphate absorption, promotes renal tubular reabsorption of calcium, and stimulates osteoclast activity to mobilize calcium from bone, thereby maintaining serum calcium and phosphate homeostasis.
400-800 IU orally once daily for vitamin D deficiency prevention; 50,000 IU orally once weekly for 8 weeks for deficiency treatment.
600-800 IU (15-20 mcg) orally once daily for adults 19-70 years; 800 IU (20 mcg) orally once daily for adults >70 years. For deficiency: 50,000 IU (1.25 mg) orally once weekly for 8 weeks, then maintenance as above.
None Documented
Clinical Note
moderateErgocalciferol + Hydrochlorothiazide
"Ergocalciferol may increase the hypercalcemic activities of Hydrochlorothiazide."
Clinical Note
moderateErgocalciferol + Bendroflumethiazide
"Ergocalciferol may increase the hypercalcemic activities of Bendroflumethiazide."
Clinical Note
moderateErgocalciferol + Methyclothiazide
"Ergocalciferol may increase the hypercalcemic activities of Methyclothiazide."
Clinical Note
moderateErgocalciferol + Hydroflumethiazide
None Documented
Terminal half-life is approximately 19 to 48 hours in healthy adults following oral administration. Due to extensive tissue storage, the functional half-life may be prolonged to weeks to months in cases of toxicity.
Terminal elimination half-life of 25-hydroxyvitamin D is 2-3 weeks (15-21 days), reflecting slow turnover and tissue storage, clinically important for dosing intervals.
Primarily excreted in bile and feces as metabolites; less than 5% excreted unchanged in urine. Renal excretion of metabolites accounts for approximately 2-4% of the dose.
Primarily fecal via bile (approximately 50-60% of metabolites), renal excretion accounts for <4% of unchanged vitamin D and its metabolites, mainly as water-soluble conjugates.
Category A/B
Category C
Vitamin D
Vitamin D
"Ergocalciferol may increase the hypercalcemic activities of Hydroflumethiazide."