The short answer
St John’s wort should be checked with your prescriber before use with labetalol. Its effects on other medicines do not establish how much it changes this exact treatment.
What this answer covers
Oral labetalol with the exact supplement preparation described below.
- Supplement or preparation
- Hypericum perforatum
- Medication ingredient
- labetalol
The herb can change some drug-handling pathways
An older-volunteer probe study showed enzyme changes after a specific St John’s wort preparation. The study did not administer labetalol and cannot supply its interaction size or clinical failure rate.
The exact medicine matters
Labetalol is mainly converted to glucuronide metabolites. A result from a CYP3A probe medicine does not by itself prove that St John’s wort lowers labetalol exposure.
Starting and stopping the product need review
St John’s wort has important interactions with several medicines. Bring the exact preparation and the full medication list to the prescriber before changing it. No hours-apart strategy was established for this pair.
Keep the prescribed treatment plan
Do not stop labetalol abruptly or adjust the dose to compensate for a supplement. Bring the product label and your recent blood-pressure and pulse readings to your pharmacist or prescriber so any change can be assessed in context.
Evidence and practical considerations
Absorption & effectiveness
St John’s wort should be checked with your prescriber before use with labetalol. Its effects on other medicines do not establish how much it changes this exact treatment.
- Exact scope
- Oral labetalol with the exact supplement preparation described below. with Oral labetalol; intravenous cases are identified as indirect route evidence where discussed.
- Medication form and route
- oral
What remains uncertain
- Other-drug enzyme induction is indirect; no exact labetalol exposure or absorption study established. Labetalol is mainly glucuronidated, so CYP3A probe findings cannot be treated as measured labetalol loss.
Factors that may matter: Exact ingredient and preparation; Kidney function and clinical indication; Concomitant medicines.
Read the supporting source summaries
Source 1: Current U.S. regulatory product labeling
dailymed.nlm.nih.gov · Source check Sep 10, 2026
Population: Patients prescribed oral labetalol.
Oral labetalol undergoes extensive first-pass metabolism, mainly glucuronide conjugation. Food increases bioavailability. This is separate from intravenous exposure and emergency treatment.
How this applies: Exact active-ingredient and oral-route context.
Label omission of an herb does not prove safety. No invented exact supplement interaction rate or universal spacing rule.
Source 2: Original human study
pubmed.ncbi.nlm.nih.gov · Source check Sep 10, 2026
Population: Twelve healthy older volunteers.
St John’s wort induced selected enzymes. Ginseng produced a small CYP2D6 marker change judged unlikely clinically relevant.
How this applies: Supports mechanism-specific limits, not blanket extrapolation.
No exact beta-blocker co-use. A probe marker is not a measured change in another drug, and bisoprolol is not a CYP2D6 substrate per its label.
Source 3: Federal supplement guidance
nccih.nih.gov · Source check Sep 10, 2026
Population: People considering the named supplement.
St John’s wort has important interactions with several named medicines; medication review is advised.
How this applies: Does not itself establish reduced bisoprolol or labetalol exposure.
General safety guidance does not quantify an exact beta-blocker interaction or establish a protective interval.
Research assessment: · Open full citations ↗
Review and change history
- Publication status
- Published research summary
- Clinical review
- Not yet recorded
| Date | Update |
|---|---|
| Article prepared | |
| Initial source-checked research draft with exact preparation limits, contrary findings and source-access details. Clinical review not recorded. | |
| Research summary published |
Article revision: 30daadd9dfc4ea01
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.