What kind of interaction is it?

Contraindicated: the two should not be combined; the risk outweighs any benefit.

Is this interaction backed by published research?

Yes. NutriStack lists 2 citation rows for the Fluvoxamine + St. John's Wort pair, each linking to PubMed by PMID where available. Full sourcing methodology at https://nutristackapp.com/methodology/interactions.

Interaction databaseSupplement × PrescriptionReviewed May 2026

Fluvoxamine and St. John's Wort, contraindicated.

Q: Can I take Fluvoxamine and St. John's Wort together?

No. Fluvoxamine and St. John's Wort are contraindicated together. St. John's Wort has SSRI-like activity and is a strong CYP3A4/2C9 inducer. Combined with fluvoxamine, the additive serotonergic load can trigger serotonin syndrome (tremor, agitation, hyperthermia, clonus). St. John's Wort is contraindicated with all SSRIs for this reason.

Q: How does this affect a NutriStack Stack Score?

-25 to your Stack Score per scored contraindication row.

St. John's Wort has SSRI-like activity and is a strong CYP3A4/2C9 inducer. Combined with fluvoxamine, the additive serotonergic load can trigger serotonin syndrome (tremor, agitation, hyperthermia, clonus). St. John's Wort is contraindicated with all SSRIs for this reason.

2 primary source citations. Strong evidence. Last verified May 30, 2026.

Open the interaction checker →Read the methodology

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.

Sourcing standards·Evidence tiers

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: Fluvoxamine and St. John's Wort
Pair type: Contraindicated
Evidence (highest tier): Strong
Source citations: 2 sources
Stack Score effect: −25 to your Stack Score (per scored contraindication row).
Scope: Supplement × Prescription
Last verified: May 30, 2026

Contraindicated · Strong evidence

Contraindicated

What is happening. St. John's Wort has SSRI-like activity and is a strong CYP3A4/2C9 inducer. Combined with fluvoxamine, the additive serotonergic load can trigger serotonin syndrome (tremor, agitation, hyperthermia, clonus). St. John's Wort is contraindicated with all SSRIs for this reason.

Mechanism. St. John's Wort constituents (hyperforin, hypericin) inhibit synaptic monoamine reuptake including serotonin. Combined with fluvoxamine's SERT blockade, synaptic serotonin can rise to toxic levels.

Recommendation. Do not combine St. John's Wort with fluvoxamine. Stop St. John's Wort at least 2 weeks before starting fluvoxamine.

Sources (2)

Stack Score

How this pair moves the number.

Effect on the composite score

If both Fluvoxamine and St. John's Wort are in the same stack, this pair applies −25 to your Stack Score (per scored contraindication row).

The full algorithm, the clamping rules, and four worked stacks are documented at /methodology/stack-score.

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