NutriStack
Colchicine and Vitamin B12, a conflict.
Colchicine causes dose-dependent, reversible malabsorption of vitamin B12 by reducing the number of intrinsic factor-vitamin B12 receptors in the ileal mucosa. Chronic colchicine use can lead to clinically significant B12 deficiency, manifesting as megaloblastic anemia and potentially irreversible peripheral neuropathy or subacute combined degeneration of the spinal cord. The neuropathy from B12 deficiency may be difficult to distinguish from colchicine-induced neuropathy.
One pair, every claim cited. The two substances, the type, the mechanism, the recommendation, and the primary literature.
Same shape as the other 1,729 pairs in the public database.
From the interaction database
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
- Colchicine and Vitamin B12
- Pair type
- Conflict
- Evidence (highest tier)
- Strong
- Source citations
- 2 sources
- Stack Score effect
- −10 to your Stack Score (per scored conflict row).
- Scope
- Supplement × Prescription
- Last verified
- May 30, 2026
Conflict · Strong evidence
Conflict
What is happening. Colchicine causes dose-dependent, reversible malabsorption of vitamin B12 by reducing the number of intrinsic factor-vitamin B12 receptors in the ileal mucosa. Chronic colchicine use can lead to clinically significant B12 deficiency, manifesting as megaloblastic anemia and potentially irreversible peripheral neuropathy or subacute combined degeneration of the spinal cord. The neuropathy from B12 deficiency may be difficult to distinguish from colchicine-induced neuropathy.
Mechanism. Colchicine disrupts microtubule-dependent intracellular transport in ileal enterocytes, reducing the quantity and function of intrinsic factor-cobalamin receptors (cubilin-amnionless complex) on the brush border membrane. This impairs the receptor-mediated endocytosis of the intrinsic factor-B12 complex in the terminal ileum, the exclusive site of active B12 absorption.
Recommendation. Monitor vitamin B12 levels annually in patients on chronic colchicine therapy. Consider prophylactic B12 supplementation (1000 mcg sublingual daily or monthly B12 injections) for long-term users. Sublingual or injectable B12 bypasses the intestinal absorption defect caused by colchicine. Report any numbness, tingling, or balance problems promptly.
Stack Score
How this pair moves the number.
Effect on the composite score
If both Colchicine and Vitamin B12 are in the same stack, this pair applies −10 to your Stack Score (per scored conflict row).
The full algorithm, the clamping rules, and four worked stacks are documented at /methodology/stack-score.
Check your full routine
One pair was the worked example. NutriStack runs every pair in your stack at once.
Drop in your supplements and prescriptions and the public database surfaces every interaction, synergy, timing rule, and contraindication, every one linked to its primary source.