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Interaction Checker

Check interactions

Add your supplements, foods, meals — and any medications you take — to see how they interact. Findings are grouped by severity: what to avoid, what needs care or timing, and what actually works better together.

Vitamin K

Add more (1/12)

Avoid

3 · Don't combine without medical guidance
Avoid
Vitamin KWarfarin (Coumadin)

Vitamin K directly counteracts warfarin — it can restore clotting and raise clot risk.

Why: Vitamin K is the antidote to warfarin; it regenerates the clotting factors warfarin suppresses.

Do not start/stop vitamin K without your prescriber; keep intake consistent and monitor INR.

Curated
Avoid
Vitamin KAcenocoumarol

Reduces anticoagulant effect

Why: Same as warfarin - vitamin K antagonism

Known interaction
Avoid
Vitamin KPhenprocoumon

Reduces anticoagulant effect

Why: Vitamin K antagonist anticoagulant

Known interaction

Caution

8 · Combine carefully — read the note
Caution
Vitamin KBroad-spectrum antibiotics

Antibiotics kill gut bacteria that produce vitamin K2; may need more K

Why: Reduced intestinal vitamin K synthesis

Known interaction
Caution
Vitamin KCephalosporins

Can cause vitamin K deficiency; bleeding risk

Why: Interfere with vitamin K recycling

Known interaction
Caution
Vitamin KCholestyramine (Questran)

Reduces vitamin K absorption

Why: Binds fat-soluble vitamins in gut

Known interaction
Caution
Vitamin KColestipol

Reduces vitamin K absorption

Why: Bile acid binding

Known interaction
Caution
Vitamin KOrlistat (Alli, Xenical)

Reduces vitamin K absorption

Why: Blocks fat absorption including fat-soluble vitamins

Known interaction
Caution
Vitamin KHigh-dose Vitamin E

High vitamin E may interfere with vitamin K function

Why: Competitive inhibition of vitamin K-dependent clotting

Known interaction
Caution
Vitamin KMineral oil

Reduces vitamin K absorption

Why: Fat-soluble vitamin binding

Known interaction
Caution
Vitamin KWarfarin - must keep intake consistent

Vitamin K: Warfarin - must keep intake consistent

Known interaction

Monitor / Timing

7 · Usually fine — mind timing or watch for effects
Monitor / Timing
Vitamin KRivaroxaban (Xarelto)

Minimal interaction - does not depend on vitamin K

Why: Direct factor Xa inhibitor - not vitamin K dependent

Known interaction
Monitor / Timing
Vitamin KApixaban (Eliquis)

Minimal interaction

Why: Direct factor Xa inhibitor

Known interaction
Monitor / Timing
Vitamin KDabigatran (Pradaxa)

Minimal interaction

Why: Direct thrombin inhibitor

Known interaction
Monitor / Timing
Vitamin KHeparin

No significant interaction

Why: Different mechanism

Known interaction
Monitor / Timing
Vitamin KFluoroquinolones

May reduce vitamin K levels

Why: Gut bacteria disruption

Known interaction
Monitor / Timing
Vitamin KColesevelam

May reduce vitamin K absorption

Why: Less effect than older agents

Known interaction
Monitor / Timing
Vitamin KHigh-dose Vitamin A

May interfere with vitamin K absorption

Why: Competition for absorption

Known interaction
Not medical advice. This tool surfaces well-established and known interactions from our reference data and curated rules. It is not exhaustive, can’t see your full health picture, and an absence of findings does not mean a combination is safe. Always consult a doctor or pharmacist about your supplements and medications.