The short answer
Have your full medication list checked before adding St. John’s wort. It has important interactions with many medicines, but the sources inspected do not establish a clonidine-specific interaction or an hours-apart schedule that makes this pair safe.
What this answer covers
Oral Hypericum perforatum with oral clonidine. Results from other Hypericum species or isolated constituents are not assigned to this product.
- Supplement or preparation
- St. John’s wort
- Medication ingredient
- clonidine
What is known about this exact pair?
The evidence located did not establish that oral St. John’s wort changes clonidine levels or that the two require a particular separation interval. That uncertainty should be stated directly, rather than turning the herb’s many other interactions into proof about clonidine.
Does the animal study answer the question?
A study compared Hypericum extract with clonidine for morphine withdrawal in rats. The herb and clonidine were separate treatments, each used with morphine. It did not test taking the herb and clonidine together in people and cannot validate a household dosing schedule.
Why still review the full medicine list?
St. John’s wort can alter the effects of several important medicines. A person taking clonidine may also use one of those medicines. The practical review therefore needs all prescriptions, nonprescription products and the actual herb preparation, rather than this pair alone.
What should happen next?
Discuss adding or stopping the herb with your pharmacist or prescriber. A generic instruction to take it a few hours away from clonidine is not supported by the inspected research. Continue clonidine as prescribed while that review is arranged.
Evidence and practical considerations
Timing & monitoring
No verified exact-pair human interaction or protective spacing interval was found. General Hypericum interaction risk requires a complete medication review.
- Exact scope
- Oral Hypericum perforatum with oral clonidine. Results from other Hypericum species or isolated constituents are not assigned to this product. with Clonidine, RxCUI 2599, IN. The inspected oral immediate-release clonidine hydrochloride label explicitly identifies its clonidine free-base equivalent. That salt-to-active-ingredient bridge is restricted to the labeled oral formulation; patch, epidural and extended-release regimens are not assigned the same exposure automatically.
- Medication form and route
- oral
What remains uncertain
- The apparent exact-name study is an animal comparator design, not coadministration.
Factors that may matter: exact product and dose; baseline blood pressure; other medicines.
Read the supporting source summaries
Source 1: government botanical reference
nccih.nih.gov · Source check Sep 10, 2026
Population: People considering Hypericum perforatum.
Documents important interactions with multiple medicines and advises medication review.
How this applies: Supports reviewing the full medicine list without assuming that every known interaction applies to clonidine.
No clonidine-specific clinical finding or validated spacing interval is given.
Source 2: original animal experiment
pubmed.ncbi.nlm.nih.gov · Source check Sep 10, 2026
Population: Morphine-dependent male Wistar rats.
Both interventions reduced withdrawal behaviors, with dose-dependent differences.
How this applies: Explains why an apparently matching paper does not verify the existing combination warning.
Animal comparator study, not Hypericum-clonidine coadministration, hypertension treatment or human absorption research.
Source 3: regulatory product labeling
dailymed.nlm.nih.gov · Source check Sep 10, 2026
Population: People prescribed oral immediate-release clonidine.
Describes blood-pressure lowering, sedation, interactions with other sedating drugs, and potentially severe rebound hypertension after abrupt withdrawal.
How this applies: Defines medication context and prevents an unsupported recommendation to stop clonidine.
Does not directly test the botanical combinations in this batch. The free-base bridge is explicit in Description.
Research assessment: · Open full citations ↗
Review and change history
- Publication status
- Published research summary
- Clinical review
- Not yet recorded
| Date | Update |
|---|---|
| Article prepared | |
| Original article drafted after source checks. Exact preparation, route, contrary evidence and claim limitations recorded for review. | |
| Research summary published |
Article revision: 834ab119b6b914fe
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.