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Oestrogen (HRT) Pregnancy: UK SPC §4.6 (Zumenon): Zumenon is not indicated during pregnancy. If pregnancy occurs during medication with Zumenon, treatment should be withdrawn immediately. The results of most epidemiological studies to date relevant to inadvertent foetal exposure to oestrogens indicate no teratogenic or foetotoxic effects. Lactation: Zumenon is not indicated during lactation.

Estradiol

Brand names: Estraderm, Estradot, Sandrena, Oestrogel, Vagifem, Femseven

Estradiol is the principal natural oestrogen, prescribed in gynaecology for menopausal hormone replacement and other oestrogen-deficiency states.

Adult dose

Dose: ORAL estradiol tablets only (Zumenon): hormone replacement therapy (HRT) for oestrogen deficiency symptoms in postmenopausal women at least 6 months since last menses. Start with Zumenon 1 mg, one tablet daily; depending on clinical response adjust to individual need; if oestrogen-deficiency complaints are not ameliorated, increase to Zumenon 2 mg, one tablet daily (each 2 mg tablet contains 2 mg estradiol as hemihydrate). Use the lowest effective dose for the shortest duration. In women with a uterus, add a progestogen for 12-14 days each month to reduce the risk to the endometrium; it is not recommended in hysterectomised women unless there is a previous diagnosis of endometriosis.
Route: Oral
Frequency: One tablet once daily, taken continuously without a break between packs, with or without food
VERBATIM UK SPC §4.2 (ZUMENON 2MG FILM-COATED TABLETS, PL440810046, Exeltis Healthcare S.L.): 'One tablet to be taken orally Zumenon is an oestrogen only continuous HRT for women with or without a uterus. In women with a uterus, a progestogen should be added to Zumenon for 12-14 days each month to reduce the risk to the endometrium. Unless there is a previous diagnosis of endometriosis, it is not recommended to add a progestogen in hysterectomised women. For initiation and continuation of treatment of postmenopausal symptoms, the lowest effective dose for the shortest duration (see also section 4.4) should be used. In general, treatment should start with Zumenon 1mg. Depending on the clinical response, the dosage can afterwards be adjusted to individual need. If the complaints linked to oestrogen deficiency are not ameliorated the dosage can be increased by using Zumenon 2mg.' 'The dosage is one tablet per day. Zumenon should be taken continuously without a break between packs. Zumenon can be taken with or without food. If a dose has been forgotten, it should be taken as soon as possible. When more than 12 hours have elapsed, it is recommended to continue with the next dose without taking the forgotten tablet. In the case of a missed or delayed dose the likelihood of breakthrough bleeding or spotting may be increased.' §4.1: 'Hormone replacement therapy (HRT) for oestrogen deficiency symptoms in postmenopausal women at least 6 months since last menses.' 'The experience treating women older than 65 years is limited.' STRENGTH (§2): 'Each tablet contains 2 mg estradiol (as hemihydrate)'; the 1 mg strength is named in §4.2 ('Zumenon 1mg') but its composition is not printed in the fetched §2. STARTING (§4.2): women not on HRT who are amenorrhoeic or hysterectomised, or who switch from a continuous combined HRT, may start on any convenient day; women transferring from a cyclic or continuous sequential regimen start the day after completing it; if menstruating regularly, start on day one of bleeding. SCOPE - ROUTES NOT COVERED: this SPC is the ORAL tablet only. The page's other routes and brands (transdermal patches such as Estraderm, Estradot and Femseven; gels such as Sandrena and Oestrogel; vaginal Vagifem) are NOT covered; their doses are in micrograms per day or per application and differ, and no figure from this SPC applies to them. The SPC prints no maximum daily dose, so none is given. Endometrial safety of added progestogens has not been demonstrated for oral estradiol doses above 2 mg (§4.4). Not for use in children: 'There is no relevant indication for the use of Zumenon in the paediatric population.' Some sections of the product information we used were incomplete — check the full SPC.

Dose adjustments

Renal

UK SPC §4.2 prints no renal impairment dose adjustment (no figure given).

Hepatic

UK SPC §4.2 prints no hepatic dose adjustment. §4.3: contraindicated in acute liver disease, or a history of liver disease as long as liver function tests have failed to return to normal; §4.4: stop therapy for jaundice or deterioration in liver function.

Dose independently re-sourced from UK Summary of Product Characteristics (SPC) via MHRA Products — clinician-reviewed. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

  • Known, past or suspected breast cancer
  • Known or suspected oestrogen-dependent malignant tumours (e.g. endometrial cancer)
  • Undiagnosed genital bleeding
  • Untreated endometrial hyperplasia
  • Previous or current venous thromboembolism (deep vein thrombosis, pulmonary embolism)
  • Known thrombophilic disorders (e.g. protein C, protein S, or antithrombin deficiency)
  • Active or recent arterial thromboembolic disease (e.g. angina, myocardial infarction)
  • Acute liver disease, or a history of liver disease as long as liver function tests have failed to return to normal
  • Known hypersensitivity to the active substance or to any of the excipients
  • Porphyria

Side effects

  • NOTE: §4.8 and §4.4 are truncated at the source-fetch limit, and the frequency columns of the §4.8 table are not legible in the extracted text, so this list names reactions without frequencies and is not the complete profile
  • Table of HRT-reported effects includes: vaginal candidiasis, hypersensitivity, weight increased or decreased, haemolytic anaemia, nervousness, depressed mood, anxiety, libido changes, headache, dizziness, migraine, visual disturbances, intolerance to contact lenses, palpitations, hypertension, peripheral vascular disease, varicose vein, venous thromboembolism, nausea, abdominal pain, dyspepsia, bloating, vomiting, gall bladder disorder, rash, pruritus, urticaria, erythema nodosum, hirsutism, acne, leg and muscle cramps, back pain, metrorrhagia, uterine/vaginal bleeding including spotting, pelvic pain, change in cervical secretion, menorrhagia, breast pain/tenderness, breast enlargement, premenstrual-like symptoms, vaginal discharge, dysmenorrhoea, asthenia, peripheral oedema, fatigue
  • Frequency unknown, reported with estradiol treatment: breast cancer; oestrogen-dependent neoplasms (e.g. endometrial and ovarian cancer); increase in size of leiomyoma; probable dementia over the age of 65; chorea; exacerbation of epilepsy; stroke; arterial thromboembolism (angina, myocardial infarction); venous thromboembolism; pancreatitis (in women with pre-existing hypertriglyceridaemia); gastro-oesophageal reflux disease; abnormal hepatic function sometimes with jaundice; angioedema, chloasma, erythema multiforme, vascular purpura; urinary incontinence; fibrocystic breast disease
  • §4.4: endometrial cancer risk among oestrogen-only users is reported as 2- to 12-fold greater compared with non-users, depending on duration and dose, and may remain elevated for at least 10 years after stopping; HRT is associated with a 1.3-3 fold risk of venous thromboembolism, more likely in the first year of HRT
  • §4.8: an up to 2-fold increased risk of breast cancer diagnosis is reported with combined oestrogen-progestogen therapy (the rest of the section was truncated at the fetch limit)

Interactions

  • Enzyme inducers (CYP450 2B6, 3A4, 3A5, 3A7): anticonvulsants (phenobarbital, phenytoin, carbamazepine) and anti-infectives (rifampicin, rifabutin, nevirapine, efavirenz) may increase oestrogen metabolism and impair efficacy
  • Ritonavir and nelfinavir show inducing properties when used with steroid hormones
  • St John's wort (Hypericum perforatum) may induce oestrogen and progestogen metabolism via CYP3A4, with decreased effect and changes in the uterine bleeding profile
  • Oestrogens may inhibit CYP450 enzymes: plasma increase up to toxic levels of tacrolimus, ciclosporin, fentanyl and theophylline is possible, so careful monitoring and a dose decrease of these may be necessary
  • Lamotrigine: oestrogen-containing hormone contraceptives significantly decrease its plasma concentration; a similar interaction is expected with HRT, which may reduce seizure control
  • HCV combination regimens (ombitasvir/paritaprevir/ritonavir and dasabuvir, glecaprevir/pibrentasvir, sofosbuvir/velpatasvir/voxilaprevir): ALT elevations were seen with ethinylestradiol-containing medicines; with estradiol the rate was similar to no oestrogen but numbers were limited (the §4.5 text is truncated at the source-fetch limit, so this list is partial)

Monitoring

  • Careful appraisal of the risks and benefits at least annually; HRT only continued as long as the benefit outweighs the risk
  • Before initiating or reinstituting HRT take a complete personal and family medical history; pelvic and breast examination guided by this; periodic check-ups adapted to the individual woman
  • Women should be advised what breast changes to report; imaging such as mammography in line with accepted screening practice (HRT can increase the density of mammographic images)
  • Immediate withdrawal for: jaundice or deterioration in liver function; significant increase in blood pressure; new onset of migraine-type headache; pregnancy; or discovery of a contraindication
  • Close supervision if present, previous or aggravated by pregnancy or earlier hormone treatment: uterine fibroids or endometriosis; thromboembolic risk factors; risk factors for oestrogen-dependent tumours; hypertension; liver disorders (e.g. liver adenoma); diabetes mellitus; cholelithiasis; migraine or severe headache; systemic lupus erythematosus; history of endometrial hyperplasia; epilepsy; asthma; otosclerosis
  • Investigate breakthrough bleeding or spotting that appears after some time on therapy or continues after stopping, which may include endometrial biopsy
  • Consider adding a progestogen in hysterectomised women with known residual endometriosis (unopposed oestrogen may cause premalignant or malignant transformation)
  • Careful drug monitoring for an extended period with tacrolimus, ciclosporin, fentanyl and theophylline

Clinical monograph

How it works

Binds oestrogen receptors to restore oestrogenic effects on the endometrium, vaginal epithelium, bone and vasomotor centres, relieving symptoms of oestrogen deficiency.

Prescribing in practice

  • In women with an intact uterus, systemic oestrogen must be combined with adequate progestogen to prevent endometrial hyperplasia and carcinoma.
  • Assess venous thromboembolism, stroke and breast cancer risk before starting; transdermal routes carry a lower thrombotic risk than oral.
  • Avoid in oestrogen-dependent cancers, undiagnosed vaginal bleeding and active thromboembolic disease.

Monitoring

Review symptom control, blood pressure and breast and pelvic health periodically, and investigate any unscheduled bleeding.

Counselling the patient

  • Report unexpected vaginal bleeding, new breast lumps, or signs of a clot such as leg swelling or breathlessness.
  • Attend breast screening and cervical screening as invited.
  • Use the prescribed oestrogen and any progestogen together as directed if you have a womb.

Evidence & guidelines

NICE menopause guidance frames the benefits and risks of oestrogen-based hormone replacement therapy, including route-dependent thrombotic risk.

Reference: NICE NG23; British Menopause Society; MHRA Drug Safety Update; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

Pathways