Supplement × Prescription·Evidence index
PubMed indexes 4 records that name St. John's Wort and Verapamil together, either in the title or in an interaction, co-administration, or pharmacokinetic context. Each one is listed below with its study design and, where the abstract states one, the authors’ own conclusion, quoted and linked. This page reports that literature. It does not tell you whether to combine them.
Every statement below is attributed to a named, dated, linked source.
This page lists published research relevant to St. John's Wort and Verapamil. It deliberately does not state whether the combination is safe, whether it interacts, in which direction, at what dose, or how far apart to take them.
Strongest relevance first: papers naming both substances in the title, then human trials and systematic reviews.
“Repeated administration of St John's wort significantly decreased the bioavailability of R- and S-verapamil. This effect is caused by induction of first-pass CYP3A4 metabolism, most likely in the gut, because the jejunal permeability and the terminal half-life were unchanged for both enantiomers.”
Names both St. John's Wort and Verapamil in its title.
“Numerous interactions between herbal medicines and conventional drugs have been documented. While the significance of many interactions is uncertain, several interactions, particularly those with St John's wort, may have serious clinical consequences.”
Names St. John's Wort and Verapamil together in an interaction, co-administration, or pharmacokinetic context.
“The RH123 accumulation assay in LS180V cells can be used as a valuable screening tool to study both inhibition and induction of P-gp activity and expression. This assay has the potential to predict P-gp-mediated alterations in intestinal absorption of drugs.”
Names St. John's Wort and Verapamil together in an interaction, co-administration, or pharmacokinetic context.
Names St. John's Wort and Verapamil together in an interaction, co-administration, or pharmacokinetic context.
Search-based evidence indexes have real limits, and it is worth being explicit about them:
NutriStack is a free iPhone app for organising a supplement routine: what you take, when, and what the published record says about it. Its exploratory interaction checker covers St. John's Wort, Verapamil, and several hundred other substances.
The checker is a research and organisation tool, not a clinical decision aid, and its per-pair assessments are excluded from search until they pass claim-level review.
NutriStack is an informational and organizational tool, not a medical service, and not a substitute for professional advice. Always consult a qualified healthcare professional before starting, stopping, or changing any supplement or medication.
