In a healthy adult, can a regimen of IV vitamin K 10 mg daily, IV thiamine 200 mg daily, oral vitamin A 50,000 IU daily, calcium‑vitamin D supplement (Shelcal XT) daily, oral vitamin C 500 mg daily, an antioxidant capsule daily, and oral vitamin E 200 IU daily cause acute kidney injury?

Risk of Acute Kidney Injury from This Vitamin Regimen

In a healthy adult, this combination of vitamins and supplements at the prescribed doses does not cause acute kidney injury and is generally safe for short-term use. However, several agents require specific monitoring and dose limitations to prevent toxicity-related AKI.

Individual Agent Analysis

High-Risk Agent: Vitamin A

• Vitamin A 50,000 IU daily poses the greatest concern because chronic high-dose supplementation can cause hypercalcemia-mediated AKI, though this typically requires prolonged exposure (weeks to months) rather than acute administration 1.
• The dose of 50,000 IU daily exceeds the U.S. Recommended Dietary Allowance (RDA) for adults (900 mcg RAE or approximately 3,000 IU), and the FDA label for high-dose vitamin A products warns that doses above the RDA should be limited in duration 2.
• Limit vitamin A 50,000 IU to a maximum of 1–2 weeks unless treating documented severe deficiency; prolonged use at this dose increases the risk of hypervitaminosis A with secondary hypercalcemia and potential AKI 1.

Moderate-Risk Agent: Vitamin C (Limcee 500 mg)

• Vitamin C 500 mg daily is well below nephrotoxic thresholds and does not cause AKI in healthy adults 2, 3.
• The FDA label for intravenous ascorbic acid (ASCOR) warns of oxalate nephropathy only with prolonged high-dose infusion (typically >1 gram/day IV for extended periods), not with oral doses of 500 mg 2.
• Oral vitamin C 500 mg daily is protective rather than harmful in AKI models, functioning as an antioxidant that reduces reactive oxygen species and oxidative tubular damage 3.
• No dose adjustment or discontinuation is needed for vitamin C 500 mg daily in healthy adults 2, 3.

Low-Risk Agents: Thiamine, Vitamin K, Vitamin E

• Thiamine 200 mg IV daily is safe and does not cause AKI; in fact, thiamine supplementation is recommended during continuous renal replacement therapy to replace dialysate losses (approximately 4 mg/day lost in effluent) 4.
• Vitamin K 10 mg IV daily does not cause AKI and is commonly used for coagulopathy correction without renal toxicity 4.
• Vitamin E 200 IU daily (Evion 200) is protective against AKI in preclinical models through antioxidant mechanisms and does not cause kidney injury at this dose 5.

Negligible-Risk Agents: Calcium-Vitamin D (Shelcal XT), Antioxidants

• Shelcal XT (calcium with vitamin D3) does not cause AKI when used at standard supplementation doses; AKI from vitamin D occurs only with megadoses (cumulative doses ≥3.6 million IU) that cause severe hypercalcemia 1.
• Standard vitamin D supplementation in Shelcal XT (typically 200–400 IU) is far below toxic thresholds 1.
• Antioxidant capsules (Antoxid) do not cause AKI and may theoretically reduce oxidative stress in renal tubules 3, 5.

Key Monitoring Parameters

• Check serum calcium weekly if vitamin A 50,000 IU is continued beyond 2 weeks, because hypercalcemia is the mechanism linking high-dose fat-soluble vitamins to AKI 1.
• Measure serum creatinine at baseline and after 1 week to detect any subclinical renal dysfunction, particularly if the patient has unrecognized chronic kidney disease 6, 7.
• Discontinue vitamin A immediately if serum calcium rises above 10.5 mg/dL or if creatinine increases ≥0.3 mg/dL within 48 hours (KDIGO Stage 1 AKI criteria) 6, 1.

Common Pitfalls to Avoid

• Do not assume "natural" vitamins are harmless; fat-soluble vitamins (A, D, E, K) accumulate in tissues and can cause toxicity with prolonged high-dose use 4, 1.
• Avoid combining this regimen with other nephrotoxic drugs (NSAIDs, ACE inhibitors, ARBs, aminoglycosides) without close monitoring, as polypharmacy increases AKI risk through additive mechanisms 4, 6.
• Recognize that baseline renal function matters; if the patient has undiagnosed CKD stage 4 (eGFR <30 mL/min/1.73 m²), even standard vitamin doses may require adjustment 7.
• Do not continue high-dose vitamin A beyond the treatment of documented deficiency; the Mayo Clinic guideline notes that multiple vitamin supplements add complexity and cost without preventive benefit in community-dwelling adults 4.

Evidence Summary

The KDIGO guideline emphasizes drug stewardship and identification of nephrotoxic combinations as key AKI prevention strategies 4. Multiple vitamin supplementation lacks evidence for mortality or cardiovascular benefit and contributes to medication burden 4. High-dose vitamin D (megadoses) causes AKI through hypercalcemia-mediated mechanisms, but standard supplementation is safe 1. Vitamin C and vitamin E are protective antioxidants in AKI models rather than causative agents 3, 5.