Burosumab
Severe
Database
Drug interaction classified as: synergy
Source: DDInter
Drug reference
Calcitriol
Active vitamin D3 metabolite (hormone) · Calcium/Vitamin D
Also known as 1,25-dihydroxycholecalciferol, Rocaltrol, Calcijex
START
Baseline calcium, phosphate, PTH, 25-OH vitamin D, creatinine. Ensure phosphate controlled before starting (Ca x P product <55 mg²/dL²).
TYPICAL MAX
2mcg/day. Monitor for hypercalcemia (constipation, confusion, polyuria, polydipsia).
STOP IF
Serum calcium >10.5 mg/dL (or 2.65 mmol/L), Ca x P product >55, signs of ectopic calcification, anaphylaxis.
WATCH
Calcium and phosphate monthly during titration, then every 3 months. PTH every 3 months (target per KDIGO). Adynamic bone disease risk if PTH suppressed too low. Concurrent phosphate binders often needed in CKD.
CDSCO approvedJan AushadhiATC A11CC04
KDIGO 2024 + manufacturer label
- ONSET
- 4h · Calcium absorption 2-6 hours
- PEAK
- 4.5h · Tmax 3-6 hours
- t½
- 6.5h · t½ 5-8 hours
- DURATION
- 3d · Effects persist 3-5 days
EXCRETION
Fecal (~50%), renal metabolites
route + CYP
INTERACTIONS
8 major
SEVERE in our sources
PREGNANCY
Use only if clearly needed; monitor calcium closely. Crosses placenta; may affect fetal calcium metabolism.
FDA category + note
Top interactionssee all 12 →
- BurosumabSevereDatabaseDDInter
- CalcifediolSevereDatabaseDDInter
- CholecalciferolSevereDatabaseDDInter
- DihydrotachysterolSevereDatabaseDDInter
Available in India
15 branded formulations and 86 fixed-dose combinations. Look up specific brands in the Drugs workspace.
Jan Aushadhi — generic available at GoI pharmacies
Mechanism
The biologically active form of vitamin D. Binds to vitamin D receptor (VDR) in intestine, bone, kidney, and parathyroid gland, increasing intestinal calcium and phosphate absorption, promoting bone mineralization, and suppressing PTH synthesis. Does not require renal 1α-hydroxylation (unlike cholecalciferol/ergocalciferol).
Indications
Secondary hyperparathyroidism in CKD (stages 3-5D)Hypocalcemia in hypoparathyroidismRickets / osteomalacia (vitamin D-dependent types, malabsorption)Psoriasis (topical)Osteoporosis (with calcium, in patients unable to activate vitamin D)
Dosing
- Adult
- CKD (dialysis): 0.25mcg PO daily initially, titrate by 0.25mcg q2-4 weeks to target PTH 150-300 pg/mL (KDOQI) or 2-9x ULN (KDIGO). Usual range 0.25-1mcg daily. Hypoparathyroidism: 0.25mcg BID, titrate to normocalcemia. Max 2mcg/day.
- Pediatric
- CKD: 0.01-0.05mcg/kg/day. Hypoparathyroidism: 0.04-0.08mcg/kg/day in 2 divided doses.
- Renal adjustment
- No adjustment (active form; no renal activation needed).
- Hepatic adjustment
- No adjustment.
- Geriatric
- Start at low end; increased hypercalcemia risk; monitor calcium and creatinine closely.
- Max dose
- 2mcg/day (oral)
Pharmacokinetics
Onset
Intestinal calcium absorption increases within 2-6 hours; PTH suppression within days
Peak effect
Tmax 3-6 hours (oral); PTH suppression: 1-2 weeks
Duration
3-5 days (effects persist after discontinuation)
Half-life
~5-8 hours (plasma); biological effects persist longer
Bioavailability
~70%
Protein binding
~99.9% (VDBP and albumin)
Metabolism
Hepatic via CYP24A1 (24-hydroxylation) to inactive calcitroic acid; also excreted in bile
Excretion
Fecal (~50%); renal (~16% as metabolites)
Contraindications
- Hypercalcemia
- Vitamin D toxicity
- Hypersensitivity to calcitriol
- Nephrolithiasis (calcium-based)
- Metastatic calcification
Side effects
Common
HypercalcemiaHyperphosphatemiaHeadacheNauseaPruritusPolyuria
Serious
- Severe hypercalcemia (nephrocalcinosis, arrhythmias)
- Nephrolithiasis
- Metastatic calcification (vascular, soft tissue)
- Ectopic calcification
- Adynamic bone disease (PTH oversuppression)
Pregnancy & lactation
Pregnancy
Use only if clearly needed; monitor calcium closely. Crosses placenta; may affect fetal calcium metabolism.
Lactation
Excreted in breast milk; may affect infant calcium metabolism. Monitor infant for hypercalcemia signs.
Drug interactions
Calcifediol
Severe
Database
Drug interaction classified as: synergy
Source: DDInter
Cholecalciferol
Severe
Database
Drug interaction classified as: synergy.
Source: DDInter
Dihydrotachysterol
Severe
Database
Drug interaction classified as: synergy
Source: DDInter
Doxercalciferol
Severe
Database
Drug interaction classified as: synergy.
Source: DDInter
Erdafitinib
Severe
Database
Drug interaction classified as: others
Source: DDInter
Ergocalciferol
Severe
Database
Drug interaction classified as: synergy.
Source: DDInter
Paricalcitol
Severe
Database
Drug interaction classified as: synergy.
Source: DDInter
Phenobarbitone
Moderate
Textbook
Prolonged use can cause rickets/osteomalacia.
Not explicitly stated, but implies monitoring bone health and vitamin D status, and possibly increasing calcitriol dose or supplementing calcium.
Source: KDT 7e · p343
Magnesium Containing Antacids
Moderate
Database
Increased magnesium absorption in CKD patients; risk of hypermagnesemia.
Avoid magnesium-containing products in CKD patients on calcitriol.
Source: Kimi deep-research + Cla
Phenytoin
Moderate
Database
Enzyme inducers increase calcitriol metabolism, reducing efficacy.
Monitor PTH and calcium; may need calcitriol dose increase.
Source: Kimi deep-research + Cla
Thiazide Diuretics
Moderate
Database
Thiazides reduce urinary calcium excretion; additive with calcitriol increases hypercalcemia risk.
Monitor calcium closely; may need calcitriol dose reduction.
Source: Kimi deep-research + Cla
Related guidelines
Ask House about Calcitriol
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