NutriStack
Risperidone and St. John's Wort, a conflict.
St. John's Wort induces CYP3A4, which metabolizes risperidone. Reduced risperidone levels can cause psychotic relapse.
One pair, every claim cited. The two substances, the type, the mechanism, the recommendation, and the primary literature.
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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
- Risperidone and St. John's Wort
- Pair type
- Conflict
- Evidence (highest tier)
- Moderate
- 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 · Moderate evidence
Conflict
What is happening. St. John's Wort induces CYP3A4, which metabolizes risperidone. Reduced risperidone levels can cause psychotic relapse.
Mechanism. Risperidone is metabolized by CYP2D6 and CYP3A4 to its active metabolite 9-hydroxyrisperidone. CYP3A4 induction by SJW increases clearance.
Recommendation. Avoid combining. Loss of antipsychotic effect can be dangerous.
Sources (2)
- Markowitz JS, Donovan JL, DeVane CL, et al. Effect of St John's wort on drug metabolism by induction of cytochrome P450 3A4 enzyme. JAMA. 2003;290(11):1500-1504. PMID 13129991
- Spina E, Avenoso A, Facciola G, et al. Plasma concentrations of risperidone and 9-hydroxyrisperidone: effect of comedication with carbamazepine or valproate. Ther Drug Monit. 2000;22(4):481-485. PMID 10942191
Stack Score
How this pair moves the number.
Effect on the composite score
If both Risperidone and St. John's Wort 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.
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