The short answer
A specific avoidance or spacing rule for St. John’s wort with rifampin has not been established. Have the complete tuberculosis regimen reviewed before adding the herb, because interactions with other medicines may still matter.
What this answer covers
Hypericum perforatum preparations with variable hyperforin.
- Supplement or preparation
- Hypericum perforatum
- Medication ingredient
- rifampin
The exact timing evidence is missing
The inspected sources did not establish a rifampin-specific protective interval or a universal requirement to avoid this herb. This evidence gap does not prove that co-use is safe.
Other interaction evidence cannot be reversed
Rifampin changes the handling of many other medicines. Evidence that a herb changes a different drug’s exposure does not show that it changes rifampin itself, nor does it define a safe separation schedule.
The whole regimen and preparation matter
Tuberculosis treatment often involves several medicines. Any advice needs the actual herbal species, extract and dose as well as the full medication list; a rifampin-only conclusion cannot cover every companion drug.
Review before making changes
Ask the TB clinician or pharmacist about starting or stopping the herb. Do not alter rifampin or attempt to prevent an unknown interaction by choosing a timing gap yourself.
Evidence and practical considerations
Timing & monitoring
No exact rifampin-herb avoidance or timing evidence identified. Different-drug probe effects and rifampin’s perpetrator enzyme induction do not establish an effect on rifampin or an exact gap. Full-regimen review remains appropriate.
- Exact scope
- Hypericum perforatum preparations with variable hyperforin. with Rifampin oral capsules and intravenous product in the combined RIFADIN label; antacid absorption warnings apply to oral dosing.
- Medication form and route
- oral medication; oral supplement
What remains uncertain
- No unmeasured pair incidence, blanket class transfer or arbitrary spacing interval.
Factors that may matter: Preparation; Dose; Other medicines; Organ function.
Read the supporting source summaries
Source 1: current product label
dailymed.nlm.nih.gov · Source check Sep 11, 2026
Population: People prescribed rifampin
Oral antacid precaution specifies rifampin at least1 hour before antacids. Enzyme induction may alter vitamin D metabolism; does not establish deficiency in everyone.
How this applies: Exact rifampin RxCUI 9384 IN, with stated salt/formulation/route bridge.
Exact route and formulation apply. Label precautions do not quantify untested botanical pairs or support arbitrary supplement doses.
Source 2: original human study
pubmed.ncbi.nlm.nih.gov · Source check Sep 11, 2026
Population: 12 healthy adults.
Short-term dosing had no measured CYP effect; repeated use reduced oral midazolam AUC more than IV AUC.
How this applies: Original source interpreted for rifampin only within the stated preparation and endpoint limits.
Not a direct rifampin combination trial; original preparation, dose and endpoint limits apply. No exact-pair adverse-event rate or protective spacing established.
Source 3: original human study
pubmed.ncbi.nlm.nih.gov · Source check Sep 11, 2026
Population: 20 healthy men.
Small AUC decrease considered not clinically relevant by authors; no significant Cmax or half-life change.
How this applies: Original source interpreted for rifampin only within the stated preparation and endpoint limits.
Not a direct rifampin combination trial; original preparation, dose and endpoint limits apply. No exact-pair adverse-event rate or protective spacing established.
Research assessment: · Open full citations ↗
Review and change history
- Publication status
- Published research summary
- Clinical review
- Not yet recorded
| Date | Update |
|---|---|
| Research summary published | |
| Editorial update | |
| Corrected missing spaces between numbers and units or words in the copy before registration; evidence and conclusions unchanged. | |
| Article prepared | |
| Prepared exact rifampin article with formulation-specific evidence and uncertainty. |
Article revision: e6d8ca2b125f3750
This guide brings together the evidence records used by our interaction checker. Each finding retains its own preparation limits, research date, and source summaries.
Full citations require verification. Reading this answer and the source summaries does not.
Taking other supplements or medications?
Use the checker to explore your other combinations. Ask a pharmacist to review the exact products, amounts and medical conditions in your complete list.
Open the interaction checkerInformation, not medical advice. Do not change prescribed treatment based on this guide.