NutriStack
Rizatriptan and St. John's Wort, a caution.
St. John's wort has serotonergic antidepressant activity and has documented interaction concerns with antidepressant drugs. Rizatriptan is a serotonin receptor agonist, so overlapping use may increase the risk of serotonin toxicity, although direct case evidence for this exact pair is limited. Warning signs include agitation, tremor, sweating, diarrhea, clonus, fever, or confusion.
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.
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
- Rizatriptan and St. John's Wort
- Pair type
- Caution
- Evidence (highest tier)
- Moderate
- Source citations
- 3 sources
- Stack Score effect
- −5 to your Stack Score (per scored caution row).
- Scope
- Supplement × Prescription
- Last verified
- May 30, 2026
Caution · Moderate evidence
Caution
What is happening. St. John's wort has serotonergic antidepressant activity and has documented interaction concerns with antidepressant drugs. Rizatriptan is a serotonin receptor agonist, so overlapping use may increase the risk of serotonin toxicity, although direct case evidence for this exact pair is limited. Warning signs include agitation, tremor, sweating, diarrhea, clonus, fever, or confusion.
Mechanism. St. John's wort can increase serotonergic tone through monoamine reuptake effects. Rizatriptan activates 5-HT1B/1D receptors, so combined serotonergic activity can contribute to receptor overstimulation in susceptible patients.
Recommendation. Avoid St. John's wort if you use rizatriptan for migraines. If you are already taking St. John's wort, stop it and review alternatives with your prescriber. Seek urgent care if serotonin-toxicity symptoms occur after overlap.
Sources (3)
- Lantz MS, Buchalter E, Giambanco V. St. John's wort and antidepressant drug interactions in the elderly. J Geriatr Psychiatry Neurol. 1999;12(1):7-10. PMID 10447148
- Izzo AA, Ernst E. Interactions between herbal medicines and prescribed drugs: an updated systematic review. Drugs. 2009;69(13):1777-1798. PMID 19719333
- Evans RW, Tepper SJ, Shapiro RE, Sun-Edelstein C, Tietjen GE. The FDA alert on serotonin syndrome with use of triptans combined with selective serotonin reuptake inhibitors or selective serotonin-norepinephrine reuptake inhibitors: American Headache Society position paper. Headache. 2010;50(6):1089-1099. PMID 20618823
Stack Score
How this pair moves the number.
Effect on the composite score
If both Rizatriptan and St. John's Wort 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 documented at /methodology/stack-score.
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