From the databaseWhat the row says.
Every entry follows the same shape: what is happening, the mechanism, and the recommendation.
Pair type
Timing Sensitive
Scope
Supplement × Prescription
Last verified
June 4, 2026
Timing SensitiveStrong evidence
What is happening. Cholestyramine can reduce vitamin K absorption and may increase bleeding risk or alter INR.
Mechanism. Bile acid sequestration impairs absorption of fat-soluble vitamin K.
Recommendation. Separate vitamin K from cholestyramine and monitor INR if anticoagulated or if bleeding occurs.
Stack Score
How it moves the number.
Effect on the composite score
If both Cholestyramine and Vitamin K1 are in the same stack, this pair applies −5 to your Stack Score (per scored timing-sensitive row).
The full algorithm, the clamping rules, and four worked stacks are at /methodology/stack-score.
SourcesSources, by evidence tier.
Every claim on this page is cited. PMIDs link straight to PubMed.
Reference material
1- 1DailyMed. Cholestyramine US prescribing information. 2026.Needs sourceNo link