Vitex and Metoclopramide Injection: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Metoclopramide Injection
Vitex
No brand names on record
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
What happens
Decreased effectiveness of DOPamine antagonists
Interaction Deep Dive
Theoretically, the DOPamine agonist activity of Vitex may oppose that of DOPamine antagonists, decreasing their effectiveness. Vitex has been effective in alleviating luteal phase defects due to hyperprolactinemia and in relieving symptoms related to premenstrual tension syndrome12. Vitex reduced prolactin secretion in humans 1. In vitro, Vitex inhibited prolactin release by binding to the D2 receptor 3.
Why it happens (mechanism)
DOPamine agonism of Vitex may counteract DOPamine antagonists
Literature reports
3 reports — tap to read
a) Vitex agnus castus (Vitex) effectively normalized prolactin release in a randomized double-blind, placebo-controlled trial of 52 women with luteal phase defects due to latent hyperprolactinemia. Administration of Vitex agnus castus 20 mg daily for three months reduced prolactin release (from 23.7 to 22.5 nanogram (ng)/mL; p equal to 0.23), normalized shortened luteal phases (from 5.5 days to 10.5 days; p less than 0.005), and eliminated deficits in luteal progesterone synthesis (from 2.46 ng/mL to 9.69 ng/mL; p less than 0.001). No side effects were noted 1.
b) Vitex agnus castus and pyridoxine caused a similar reduction on the premenstrual tension scale (PMTS) in a randomized, controlled trial of 127 women with PMTS. Patients taking Vitex agnus castus (Agnolyt(R)) experienced more relief from breast tenderness, inner tension, headache, edema, constipation, and depression than those taking pyridoxine. Patients in the Vitex agnus castus group receive one capsule of Agnolyt(R) and one placebo capsule daily for 3 menstrual cycles. Patients in the pyridoxine group received one placebo capsule twice daily on days 1-15 of the menstrual cycle and pyridoxine 100 mg twice daily on days 16 to 35 of the menstrual cycle for 3 menstrual cycles. Unspecified gastrointestinal disturbances occurred in the treatment group along with two cases of skin reaction and one transient headache 2.
c) In vitro, Vitex (Agnus castus) was found to bind to the D2 receptor in rat pituitary cell cultures. Basal prolactin release was significantly inhibited by 0.5 milligram (mg) and 1 mg of vitex extract/mL culture medium (p less than 0.05). Agnus castus extract doses from 0.125 mg/mL to 1 mg/mL significantly suppressed prolactin release in cells stimulated by thyrotropin releasing hormone (TRH) (p less than 0.05). DOPaminergic action was demonstrated in the rat corpus striatum membrane DOPamine receptor assay. Agnus castus extract did not affect basal luteinizing hormone (LH) or follicle-stimulating hormone (FSH), indicating selectivity for prolactin secretion, and not generalized inhibition of pituitary hormone secretion. The effect was not due to a cytotoxic effect as demonstrated by the lack of effect on the MTT-conversion test. The authors concluded that Agnus castus exerted its prolactin inhibiting effect via stimulation of D2 receptors in the pituitary 3.
Common questions
Can I take Vitex and Metoclopramide Injection together?
Decreased effectiveness of DOPamine antagonists Always confirm with your pharmacist or prescriber before making any change.
How serious is the Vitex and Metoclopramide Injection interaction?
It is rated minor. Usually limited clinical impact.
How quickly could this interaction happen?
The documented onset is "delayed". Effects tend to build up gradually over days to weeks.
How strong is the evidence for this interaction?
The evidence is graded "established". Well documented — supported by controlled studies or strong clinical data.
Questions for your pharmacist
- Does my dose of Vitex or Metoclopramide Injection need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there anything you'd monitor while I'm on both?
References (3)
- Milewicz A, Gejdel E, Sworen H, et al: Vitex agnus castus extract in the treatment of luteal phase defects due to latent hyperprolactinemia. Results of a randomized placebo-controlled double-blind study (Article in German). Arzneimittelforschung 1993; 43(7):752-756.
- Lauritzen C, Reuter HD, Repges R, et al: Treatment of premenstrual tension syndrome with Vitex agnus castus: controlled, double-blind study versus pyridoxine. Phytomedicine 1997; 4:183-189. PubMed
- Jarry H, Leonhardt S, Gorkow C, et al: In vitro prolactin but not LH and FSH release is inhibited by compounds in extracts of Agnus castus: direct evidence for a dopaminergic principle by the dopamine receptor assay. Exp Clin Endocrinol 1994; 102:448-454. DOI
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