The short answer
Vitex deserves review before use with chlorpromazine because of possible opposing dopamine-related effects. Reduced chlorpromazine absorption or loss of treatment control has not been demonstrated.
What this answer covers
Oral chlorpromazine with the exact supplement preparation described.
- Supplement or preparation
- Vitex agnus-castus
- Medication ingredient
- chlorpromazine
The proposed concern involves dopamine effects
Vitex preparations showed dopamine-related activity and changes in prolactin secretion in rat laboratory preparations. Chlorpromazine has dopamine-blocking effects, so there is a reason to ask about a possible pharmacodynamic conflict.
Official guidance remains precautionary
The Vitex monograph lists no reported interactions, while advising people using dopamine antagonists to consult a clinician because an interaction cannot be excluded. That is different from documenting treatment failure.
Absorption has not been shown to fall
The laboratory experiments did not administer Vitex with chlorpromazine to patients or measure medicine levels and symptom control. They cannot establish reduced absorption or determine whether spacing the doses helps.
Do not use the herb to adjust psychiatric treatment
Show the fruit or extract product to the prescriber before use, including if you are considering it for hormonal or prolactin-related symptoms. Do not change chlorpromazine on the basis of the theoretical interaction.
Evidence and practical considerations
Absorption & effectiveness
Vitex deserves review before use with chlorpromazine because of possible opposing dopamine-related effects. Reduced chlorpromazine absorption or loss of treatment control has not been demonstrated.
- Exact scope
- Oral chlorpromazine with the exact supplement preparation described. with Oral chlorpromazine with the stated label and formulation limits.
- Medication form and route
- oral
What remains uncertain
- Vitex monograph says no interactions reported but theoretical dopamine effects justify consultation for antagonist users. Rat pituitary receptor work is not measured human absorption/efficacy. Original Q2 insufficient, narrower consultation precaution conditional.
Factors that may matter: Exact preparation and amount; Other medicines; Seizure history, alertness or electrolyte status where relevant.
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 chlorpromazine.
May cause initial drowsiness, intensify other CNS depressants, lower the seizure threshold and cause photosensitivity. Has strong antiadrenergic and weaker peripheral anticholinergic effects.
How this applies: Exact ingredient and oral-route clinical context.
Label class warnings do not establish every exact botanical interaction, event rate or protective supplement interval.
Source 2: Regulatory herbal monograph
ema.europa.eu · Source check Sep 10, 2026
Population: People considering the covered Vitex fruit preparations.
No interactions are reported; possible dopaminergic or estrogenic effects mean interactions cannot be excluded, and dopamine antagonist users should consult a clinician.
How this applies: Supports product review without presenting a theoretical receptor interaction as measured loss of efficacy.
Precautionary guidance, not demonstrated chlorpromazine absorption or treatment failure.
Source 3: Original laboratory study
pubmed.ncbi.nlm.nih.gov · Source check Sep 10, 2026
Population: Rat pituitary cell cultures and striatal membrane preparations.
Selected preparations inhibited prolactin secretion and showed dopamine-receptor-related activity.
How this applies: Explains the proposed pharmacodynamic concern without establishing its clinical magnitude.
Not human chlorpromazine co-use, oral absorption or symptom control.
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 draft with exact preparation limits, original study findings and uncertainty. Clinical review not recorded. | |
| Research summary published |
Article revision: 9a23d04fc3564f5b
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.