What kind of interaction is it?

Caution: an interaction that may reduce efficacy or raise side-effect risk and warrants monitoring.

Is this interaction backed by published research?

Yes. NutriStack lists 1 citation row for the Cefixime + Vitamin K2 pair, each linking to PubMed by PMID where available. Full sourcing methodology at https://nutristackapp.com/methodology/interactions.

Supplement × Prescription·a caution·Insufficient evidence

Cefixime + Vitamin K2

Q: Can I take Cefixime and Vitamin K2 together?

Possibly, but with caution. Cefixime and Vitamin K2 have a documented caution-tier interaction. Broad-spectrum antibiotics including cephalosporins can suppress vitamin K-producing gut flora during prolonged or repeated courses, which may modestly lower vitamin K status. Vitamin K2 supplementation is generally protective rather than harmful in this setting.

Q: How does this affect a NutriStack Stack Score?

-5 to your Stack Score per scored caution row.

Caution Insufficient evidence

Broad-spectrum antibiotics including cephalosporins can suppress vitamin K-producing gut flora during prolonged or repeated courses, which may modestly lower vitamin K status. Vitamin K2 supplementation is generally protective rather than harmful in this setting.

Supplement × Prescription

Open the interaction checker → Read the methodology

From the database

What the row says.

Every entry follows the same shape: what is happening, the mechanism, and the recommendation.

Substances

Cefixime and Vitamin K2

Pair type

Caution

Evidence

Insufficient

Source citations

Scope

Supplement × Prescription

Last verified

June 4, 2026

CautionInsufficient evidence

What is happening. Broad-spectrum antibiotics including cephalosporins can suppress vitamin K-producing gut flora during prolonged or repeated courses, which may modestly lower vitamin K status. Vitamin K2 supplementation is generally protective rather than harmful in this setting.

Mechanism. Antibiotic-induced reduction of menaquinone-synthesizing colonic bacteria can lower endogenous vitamin K availability, an effect of clinical relevance mainly in malnourished or anticoagulated patients.

Recommendation. No routine action is needed for typical short cefixime courses. Patients on chronic anticoagulants or with poor nutritional intake should monitor for signs of bleeding and discuss vitamin K intake with their clinician.

Stack Score

How it moves the number.

Effect on the composite score

If both Cefixime and Vitamin K2 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 at /methodology/stack-score.

Sources

Sources, by evidence tier.

Every claim on this page is cited. PMIDs link straight to PubMed.

Reference material

1Shevchuk YM, Conly JM. Antibiotic-associated hypoprothrombinemia: a review of prospective studies, 1966-1988. Rev Infect Dis. 1990.Needs sourceNo link

Check your full routine

One pair was the worked example.

Drop your supplements and prescriptions into NutriStack and it runs every pair at once: every interaction, synergy, timing rule, and contraindication, each linked to its primary source.

Open the interaction checker → Browse the research index