Cholecalciferol (Vitamin D3)

Clinical Summary

Cholecalciferol (vitamin D3) is used for vitamin D supplementation and prevention/treatment of deficiency.

Documented on handwritten prescription as "Dase" — likely brand name containing vitamin D3 (cholecalciferol) 2000 IU.

Long-term continuous medication confirmed. Documented on both November 2022 medication list ("D-Rise") and May 2026 handwritten prescription ("Dase") at the same dose (2000 IU once daily morning). Brand name changed but dose is unchanged across at least 3.5 years.

Dosing History

[!info] Long-Term Continuity: at least Nov 2022 → May 2026
Dose unchanged. Brand changed D-Rise → Dase. 25-OH vitamin D has never been measured in any ingested document.

Despite 3+ years of supplementation, no 25-OH vitamin D level has been measured in any ingested source. Baseline and adequacy are unknown.

Indication

Presumed: Vitamin D supplementation / deficiency prevention

Vitamin D deficiency is common in:
- Elderly populations (Ishamma age 81)
- Limited sun exposure
- Indian population (despite sunny climate, vitamin D deficiency is highly prevalent due to cultural/clothing factors, skin pigmentation)
- Malignancy and treatment (increased bone resorption, decreased sun exposure)

Clinical rationales for Ishamma:
1. Age 81: High risk of deficiency
2. AML treatment: Bone health, immune function
3. Diabetes: Vitamin D may improve insulin sensitivity
4. General health: Bone, immune, cardiovascular benefits

Pharmacology

• Drug class: Vitamin D supplement (cholecalciferol = D3, ergocalciferol = D2)
• Mechanism: Converted in liver to 25-OH vitamin D (storage form), then in kidneys to 1,25-(OH)₂ vitamin D (active hormone). Regulates calcium/phosphate homeostasis, bone metabolism, immune function, cell growth.
• Standard dosing:
• Maintenance (normal levels): 600–1000 IU/day
• Deficiency prevention: 1000–2000 IU/day (Ishamma's current dose)
• Deficiency treatment: 50,000 IU weekly × 8 weeks, then maintenance

Monitoring

[!info] Calcium History
Ishamma had transient hypercalcemia on Jan 19, 2026 (10.9 mg/dL), which resolved spontaneously by Jan 22 (9.9 mg/dL). Etiology was unclear (granulomatous disease, malignancy-related, vitamin D excess were considered). See Calcium.

If vitamin D3 was being given at that time (unknown), it may have contributed to the hypercalcemia. At 2000 IU/day, hypercalcemia risk is low, but monitoring is prudent.

No 25-OH vitamin D lab result has been documented. Baseline vitamin D level should be obtained to confirm deficiency and guide dosing.

Drug Interactions

• Thiazide diuretics: Reduce urinary calcium excretion → increased hypercalcemia risk with vitamin D
• Digoxin: Hypercalcemia (from vitamin D excess) increases digoxin toxicity risk
• Orlistat, bile acid sequestrants: Reduce vitamin D absorption (fat-soluble vitamin)
• No significant interaction with current medications

Adverse Effects

• Hypercalcemia (from excessive dosing) — symptoms: nausea, vomiting, weakness, confusion, polyuria, kidney stones
• Hypercalciuria (increased urinary calcium → kidney stones)
• At 2000 IU/day: side effects are rare; well within safe upper limit (4000 IU/day)

Target Levels

• 25-OH vitamin D goal: 30–50 ng/mL (75–125 nmol/L)
• Deficiency: <20 ng/mL (<50 nmol/L)
• Insufficiency: 20–29 ng/mL (50–74 nmol/L)
• Optimal: ≥30 ng/mL (≥75 nmol/L)
• Toxicity: >100 ng/mL (>250 nmol/L)

Related

• Calcium — Monitor for hypercalcemia (history of transient elevation Jan 2026)
• 25-OH vitamin D — Should be checked (not yet documented)
• Diabetes Mellitus — Vitamin D may improve insulin sensitivity
• Aml — Bone health, immune support during treatment

Medication page created during ingest of 2026-05-04 handwritten prescription.