NutriStack
Topiramate and Vitamin C, a caution.
Topiramate increases kidney-stone risk by causing alkaline urine and hypocitraturia. High-dose vitamin C can increase urinary oxalate and has been associated with higher kidney-stone risk, particularly in men. Combining topiramate with high-dose vitamin C is most concerning in people with prior stones, low fluid intake, ketogenic diets, or other stone risks.
One pair, every claim cited. The two substances, the type, the mechanism, the recommendation, and the primary literature.
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What the row says.
Every entry follows the same shape: what is happening, the mechanism, the recommendation, and the primary literature.
At a glance
- Substances
- Topiramate and Vitamin C
- Pair type
- Caution
- Evidence (highest tier)
- Moderate
- Source citations
- 3 sources
- Stack Score effect
- −5 to your Stack Score (per scored caution row).
- Scope
- Supplement × Prescription
- Last verified
- May 30, 2026
Caution · Moderate evidence
Caution
What is happening. Topiramate increases kidney-stone risk by causing alkaline urine and hypocitraturia. High-dose vitamin C can increase urinary oxalate and has been associated with higher kidney-stone risk, particularly in men. Combining topiramate with high-dose vitamin C is most concerning in people with prior stones, low fluid intake, ketogenic diets, or other stone risks.
Mechanism. Topiramate promotes calcium phosphate stone risk through renal carbonic anhydrase inhibition, hypocitraturia, and elevated urine pH. Vitamin C is metabolized partly to oxalate, increasing calcium oxalate supersaturation when taken at high supplemental doses.
Recommendation. Avoid high-dose vitamin C while taking topiramate unless your clinician has a specific reason for it. Keep vitamin C near dietary or standard multivitamin amounts, maintain good hydration, and ask about urine or blood monitoring if you have a stone history. Seek care for flank pain, blood in urine, fever, or vomiting.
Sources (3)
- Lamb EJ, Stevens PE, Nashef L. Topiramate increases biochemical risk of nephrolithiasis. Ann Clin Biochem. 2004;41(Pt 2):166-169. PMID 15025812
- Ferraro PM, Curhan GC, Gambaro G, Taylor EN. Total, Dietary, and Supplemental Vitamin C Intake and Risk of Incident Kidney Stones. Am J Kidney Dis. 2016;67(3):400-407. PMID 26463139
- Massey LK, Liebman M, Kynast-Gales SA. Ascorbate increases human oxaluria and kidney stone risk. J Nutr. 2005;135(7):1673-1677. PMID 15987848
Stack Score
How this pair moves the number.
Effect on the composite score
If both Topiramate and Vitamin C are in the same stack, this pair applies −5 to your Stack Score (per scored caution row).
The full algorithm, the clamping rules, and four worked stacks are documented at /methodology/stack-score.
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