Medication · hrt progesterone

Supplements and Dydrogesterone.

Every documented pair, every citation. Below: 2 documented pairs grouped by mechanism.

Dydrogesterone, sold under the brand names Duphaston, Femoston, Femoston-conti, is hormone replacement therapy (progesterone component).

Dydrogesterone is hormone replacement therapy (the progesterone component). It is prescribed alongside oestrogen in women with an intact uterus, to oppose endometrial hyperplasia driven by oestrogen. Micronised progesterone (Utrogestan) has replaced earlier synthetic progestogens in much of UK practice, given the better metabolic and breast cancer risk profile. Mechanism is GABA-A receptor modulation in addition to progesterone receptor activity. That is why bedtime dosing is standard; the sedating effect is useful. The supplement surface is small. Progesterone is metabolised by CYP3A4 but the dose is much lower than the oestrogen counterpart. The clinical signal from supplement interactions is correspondingly quieter. Symptom relief supplements (black cohosh, ashwagandha for sleep, magnesium glycinate for waking in the night) sit on top of HRT without strong interaction signals. The clinically important point is differentiating HRT progesterone use from progestogen as a contraceptive. Different agents, different goals, different dosing.

Below are the 2 documented pairs we have explicitly assessed against Dydrogesterone in the Distil database: 2 amber. The pairs cluster around 2 mechanisms: CYP3A4 induction and Hormonal axis modulation. Every call is cited to either a clinical reference (PMID) or the British National Formulary. Anything not on this list is either still to be assessed or beyond our database scope. The checker beneath surfaces assessments by supplement, and the missing-item form at the bottom of the page routes any uncatalogued supplement into our next curation pass.

Documented interactions

CYP3A4 induction

Amber St John's Wort

St John's Wort can reduce circulating dydrogesterone levels by speeding up its breakdown. Dydrogesterone is the progestogen in HRT combinations such as Femoston, so for HRT users this can mean menopausal symptom control slips and breakthrough bleeding becomes more likely. Mention St John's Wort to your prescriber rather than starting it alongside HRT on your own.

PMID 13129991 · PMID 27444983 · BNF: Hypericum · BNF: Dydrogesterone

Reviewer-flagged: awaiting clinical-reviewer sign-off.

Hormonal axis modulation

Amber Vitex

Vitex (chasteberry) acts on the body's hormone signals: it lowers prolactin and, in lab studies, gently nudges oestrogen and progesterone receptors. Dydrogesterone is the progestogen in HRT combinations such as Femoston, so in theory vitex could pull against the hormone balance the HRT is providing, and the HRT could equally blunt what vitex is meant to do. There is no study showing this actually happens, so it is a caution rather than a firm warning. If you take HRT, it is worth mentioning vitex to your prescriber before adding it.

PMID 7890021 · PMID 14974442 · PMID 18204102 · PMID 39519010 · BNF: Dydrogesterone

Reviewer-flagged: awaiting clinical-reviewer sign-off.

What this list does not say. Pairs not flagged here are not implicitly safe. They are either not yet in our database, or fall outside our inclusion scope (food-supplement interactions only; for drug-drug interactions, the BNF is authoritative). Use the checker below to surface any supplement, and submit a missing item if you take something we have not catalogued.

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