Calcifediol
Severe
Database
Clinical effect not specified
Source: DDInter
Drug reference
Cholecalciferol
Vitamin D3 supplement / fat-soluble vitamin · Nutritional supplement
Also known as Vitamin D3, Calciol, Colecalciferol
START
Check baseline 25(OH)D level; 50,000 IU weekly x 6-8 weeks if deficient (<20 ng/mL); maintenance 1,000-2,000 IU/day; take with fatty meal
TYPICAL MAX
4,000 IU/day maintenance without monitoring; up to 10,000 IU/day short-term with calcium and 25(OH)D monitoring
STOP IF
25(OH)D >100 ng/mL, hypercalcemia, signs of toxicity
WATCH
Serum 25(OH)D at 8-12 weeks (target 30-50 ng/mL), calcium, phosphate, PTH if indicated
CDSCO approvedJan AushadhiATC A11CC05
KDIGO 2024 + manufacturer label
- ONSET
- 12h · absorption onset
- PEAK
- 2d · Absorption peak; 25(OH)D peaks at 8-12 weeks
- t½
- 2w · 25(OH)D half-life 2-3 weeks
- DURATION
- 12w · Fat-soluble; stores last weeks to months
EXCRETION
Biliary/fecal (major)
route + CYP
INTERACTIONS
7 major
SEVERE in our sources
PREGNANCY
Safe and recommended in pregnancy; 600 IU/day minimum; deficiency should be corrected
FDA category + note
Top interactionssee all 11 →
- CalcifediolSevereDatabaseDDInter
- CalcitriolSevereDatabaseDDInter
- DihydrotachysterolSevereDatabaseDDInter
- DoxercalciferolSevereDatabaseDDInter
Available in India
196 branded formulations and 86 fixed-dose combinations. Look up specific brands in the Drugs workspace.
Jan Aushadhi — generic available at GoI pharmacies
Mechanism
Prohormone converted in liver to 25-hydroxyvitamin D [25(OH)D], then in kidney to active 1,25-dihydroxyvitamin D [1,25(OH)2D, calcitriol]. Active form regulates calcium and phosphate homeostasis by enhancing intestinal absorption, renal reabsorption, and bone mobilization. Also has immunomodulatory, anti-inflammatory, and cellular differentiation effects.
Indications
Vitamin D deficiency (treatment and prevention)Osteoporosis (adjunctive therapy with calcium)Rickets and osteomalaciaHypoparathyroidism (adjunctive)Chronic kidney disease (CKD-MBD, as active vitamin D or precursor)Prevention of falls in elderlyMultiple sclerosis (adjunctive, evidence emerging)
Dosing
- Adult
- Deficiency: 50,000 IU weekly x 6-8 weeks then 1,000-2,000 IU daily maintenance. Maintenance: 600-1,000 IU/day (up to 2,000 IU). Severe deficiency: 6,000-10,000 IU daily x 8-12 weeks
- Pediatric
- Deficiency: 2,000 IU/day (<12 months) or 4,000 IU/day (>12 months) x 6-8 weeks. Maintenance: 400-600 IU/day. Rickets: 3,000-6,000 IU/day
- Renal adjustment
- No adjustment needed for cholecalciferol itself; in CKD stages 4-5, active vitamin D (calcitriol, alfacalcidol) preferred
- Hepatic adjustment
- Caution in severe hepatic impairment (reduced 25-hydroxylation); may need active forms
- Geriatric
- Standard dosing; elderly have reduced skin synthesis and increased fracture risk; 800-2,000 IU/day recommended
- Max dose
- 4,000 IU/day (maintenance upper limit without medical supervision); higher doses for short-term repletion under monitoring
Pharmacokinetics
Onset
Weeks (for deficiency correction)
Peak effect
24-48 hours for absorption; 25(OH)D peak at 2-3 months
Duration
Months (fat-soluble, stored in adipose tissue)
Half-life
Cholecalciferol: 12-24 hours; 25(OH)D: 2-3 weeks
Bioavailability
50-80% (oral, with fatty meal)
Protein binding
85-90% (bound to vitamin D-binding protein)
Metabolism
Hepatic 25-hydroxylation (CYP2R1, CYP27A1); renal 1-alpha-hydroxylation (CYP27B1)
Excretion
Biliary/fecal (major); minimal renal excretion
Contraindications
- Hypercalcemia
- Nephrolithiasis (active or history with hypercalciuria)
- Severe renal impairment (for standard cholecalciferol - use active forms in CKD stage 4-5)
- Vitamin D toxicity / hypersensitivity
- Metastatic calcification
Side effects
Common
Generally none at standard doses
Serious
- Hypercalcemia (with excessive dosing)
- Nephrocalcinosis / renal stones
- Nausea, vomiting, constipation (hypercalcemia symptoms)
- Polyuria, polydipsia
- Weakness, confusion (severe hypercalcemia)
Pregnancy & lactation
Pregnancy
Safe and recommended in pregnancy; 600 IU/day minimum; deficiency should be corrected
Lactation
Safe during breastfeeding; infant should also receive 400 IU/day supplementation
Drug interactions
Calcitriol
Severe
Database
Drug interaction classified as: synergy.
Source: DDInter
Dihydrotachysterol
Severe
Database
Clinical effect not specified
Source: DDInter
Doxercalciferol
Severe
Database
Clinical effect not specified
Source: DDInter
Erdafitinib
Severe
Database
Clinical effect not specified
Source: DDInter
Ergocalciferol
Severe
Database
Clinical effect not specified
Source: DDInter
Paricalcitol
Severe
Database
Drug interaction classified as: synergy
Source: DDInter
Corticosteroids
Moderate
Database
Steroids reduce calcium absorption and increase vitamin D metabolism; may cause bone loss
Ensure adequate vitamin D and calcium supplementation with long-term steroids
Source: Kimi deep-research + Cla
Orlistat
Moderate
Database
Fat malabsorption reduces vitamin D absorption (fat-soluble vitamin)
Take vitamin D at bedtime or separate from orlistat; monitor 25(OH)D
Source: Kimi deep-research + Cla
Phenytoin
Moderate
Database
Enzyme induction increases vitamin D metabolism; may cause vitamin D deficiency
Monitor 25(OH)D levels; may need higher vitamin D doses
Source: Kimi deep-research + Cla
Thiazide Diuretics
Moderate
Database
Thiazides reduce urinary calcium excretion; combined with vitamin D may cause hypercalcemia
Monitor calcium levels; avoid high-dose vitamin D with thiazides
Source: Kimi deep-research + Cla
1 additional low-confidence interaction hidden — those rows lack a documented mechanism or management plan in our sources.
Related guidelines
Chronic kidney disease — assessment and management
KDIGO · Nephrology · 2024
Iron deficiency anaemia in pregnancy
ICMR · Obstetrics & Gynaecology · 2022
Iron deficiency anaemia in adults
ICMR · Hematology · 2023
Chronic kidney disease — assessment and management
NICE · Nephrology · 2021
Cardiovascular disease prevention
ESC · Cardiology · 2021
Ask House about Cholecalciferol
Continue into a citation-backed clinical answer with the drug context already attached.
Sources: KD Tripathi 7e, Goodman & Gilman 14e, Katzung, BNF·Verified: 2026-05-19 · House clinical team·Cockpit curated: 2026-05-19