Carfilzomib
Severe
Database
Drug interaction classified as: synergy
Source: DDInter
Drug reference
Estradiol
Estrogen / steroid hormone / HRT · Hormone Replacement Therapy; Contraceptive (in combination); Treatment of Estrogen Deficiency
Also known as Estradiol valerate, Estradiol hemihydrate, Estradiol cypionate, Estradiol benzoate, E2
START
Lowest effective dose (0.5 mg oral or 25 mcg patch) for shortest duration; must add progestin if uterus intact; check baseline BP, mammogram, Pap smear, family history
TYPICAL MAX
2 mg/day oral; 100 mcg/day transdermal
STOP IF
VTE symptoms (leg pain, chest pain, dyspnea), migraine with aura, BP >160/100, jaundice, 5-year mark (reassess)
WATCH
BP at each visit, mammography (biennial), VTE risk assessment, uterine bleeding pattern, lipids, glucose if at risk
CDSCO approvedJan AushadhiNPPA price-controlledATC G03CA03
KDIGO 2024 + manufacturer label
- ONSET
- 1.5h · absorption onset
- PEAK
- 6h · Oral peak
- t½
- 15h · Oral: 12-18 hours
- DURATION
- 1d · 24-hour coverage (daily dosing)
EXCRETION
Renal (conjugates)
route + CYP
INTERACTIONS
9 major
SEVERE in our sources
PREGNANCY
Contraindicated in pregnancy; may cause fetal harm
FDA category + note
Top interactionssee all 10 →
- CarfilzomibSevereDatabaseDDInter
- DantroleneSevereDatabaseDDInter
- HeminSevereDatabaseDDInter
- LenalidomideSevereDatabaseDDInter
Available in India
88 branded formulations and 148 fixed-dose combinations. Look up specific brands in the Drugs workspace.
Jan Aushadhi — generic available at GoI pharmacies
Mechanism
Endogenous estrogen that binds to intracellular estrogen receptors (ER-alpha and ER-beta) in target tissues, regulating gene transcription. Modulates hypothalamic-pituitary-gonadal axis, maintains female reproductive tissues, bone density, cardiovascular health, and has neuroprotective effects. In HRT, replaces declining endogenous estrogen in menopause.
Indications
Menopausal hormone therapy (MHT) - vasomotor symptoms (hot flashes)Menopausal urogenital atrophy / vaginal drynessPrevention of postmenopausal osteoporosisHypogonadism / primary ovarian insufficiencyGender-affirming hormone therapy (feminizing)Oral contraception (in combination with progestin)Amenorrhea (estrogen deficiency-related)
Dosing
- Adult
- Oral: 0.5-2 mg/day (start 0.5 mg). Transdermal: 25-100 mcg patch twice weekly. Vaginal: 10 mcg tablet daily or 0.5-1 mg cream twice weekly. IM (depot): 1-5 mg every 3-4 weeks
- Pediatric
- Hypogonadism: start 0.3 mg/day, titrate over 2-3 years to adult dose
- Renal adjustment
- No adjustment needed
- Hepatic adjustment
- Contraindicated in severe hepatic impairment; avoid oral route in any hepatic impairment (use transdermal)
- Geriatric
- Start lowest dose (0.5 mg or 25 mcg patch); use for shortest duration; reassess need annually
- Max dose
- 2 mg/day (oral); 100 mcg/day (transdermal)
Pharmacokinetics
Onset
Hot flashes: 1-2 weeks; Bone protection: months
Peak effect
Oral: 4-8 hours; Transdermal: 24-48 hours (steady-state); IM depot: 2-4 days
Duration
Oral: 24 hours; Transdermal: 3-4 days (patch); IM: 2-4 weeks
Half-life
Oral: 12-18 hours (short due to first-pass); Transdermal: 2-4 hours (absorption-limited); Estrone sulfate: 5-16 hours
Bioavailability
Oral: 5% (extensive first-pass); Transdermal: ~95%; Vaginal: variable
Protein binding
98% (bound to SHBG and albumin)
Metabolism
Hepatic CYP3A4 (major), CYP1A2, CYP2C9; extensive first-pass to estrone and estriol
Excretion
Renal (as glucuronide and sulfate conjugates); fecal
Contraindications
- History of breast cancer or other estrogen-dependent neoplasia
- Undiagnosed abnormal vaginal bleeding
- Active or history of venous thromboembolism (DVT/PE)
- Active or history of arterial thromboembolism (stroke, MI)
- Severe hepatic impairment
- Known thrombophilic disorders
- Pregnancy
- Known hypersensitivity to estradiol
Side effects
Common
Breast tenderness/enlargementNauseaHeadacheBloating/fluid retentionBreakthrough bleeding/spottingMood changesWeight gain
Serious
- Venous thromboembolism (DVT, PE)
- Stroke
- Myocardial infarction
- Breast cancer (with prolonged combined HRT)
- Endometrial cancer (unopposed estrogen)
- Gallbladder disease
- Hypertension
- Hepatic adenoma
Pregnancy & lactation
Pregnancy
Contraindicated in pregnancy; may cause fetal harm
Lactation
May reduce milk production; excreted in breast milk; avoid during breastfeeding
Drug interactions
Dantrolene
Severe
Database
Clinical effect not specified
Source: DDInter
Hemin
Severe
Database
Drug interaction classified as: antagonism
Source: DDInter
Lenalidomide
Severe
Database
Drug interaction classified as: synergy.
Source: DDInter
Paritaprevir
Severe
Database
Drug interaction classified as: metabolism
Source: DDInter
Pomalidomide
Severe
Database
Drug interaction classified as: synergy
Source: DDInter
Rifampicin
Severe
Database
Significantly decreased plasma concentrations and efficacy of estradiol, leading to breakthrough bleeding, reduced contraceptive efficacy (if used in combination oral contraceptives), or recurrence of menopausal symptoms. This effect can persist for several weeks after rifampicin discontinuation.
Avoid concomitant use if possible. If co-administration is unavoidable, use alternative non-hormonal contraception during rifampicin treatment and for at least 4 weeks after discontinuation. For hormone replacement therapy, consider alternative routes of administration or higher doses, but efficacy may still be compromised.
Source: DDInter
Thalidomide
Severe
Database
Drug interaction classified as: synergy.
Source: DDInter
Tranexamic Acid
Severe
Database
Drug interaction classified as: synergy
Source: DDInter
Phenobarbital
Moderate
Database
Decreased plasma concentrations and efficacy of estradiol, leading to breakthrough bleeding, reduced contraceptive efficacy (if used in combination oral contraceptives), or recurrence of menopausal symptoms.
Consider alternative or additional contraception. Monitor for reduced efficacy of estradiol. Dose adjustment of estradiol may be necessary, or consider an alternative antiepileptic drug.
Source: DDInter
2 additional low-confidence interactions hidden — those rows lack a documented mechanism or management plan in our sources.
Related guidelines
Tobacco-related cancer prevention
ICMR · Oncology · 2021
Primary prevention of cardiovascular disease
AHA · Cardiology · 2019
Iron deficiency anaemia in adults
ICMR · Hematology · 2023
Iron deficiency anaemia in pregnancy
ICMR · Obstetrics & Gynaecology · 2022
Iron deficiency anaemia in pregnancy
FOGSI · Obstetrics & Gynaecology · 2017
Ask House about Estradiol
Continue into a citation-backed clinical answer with the drug context already attached.
Sources: KD Tripathi 7e, Goodman & Gilman 14e, Katzung, BNF·Verified: 2026-05-19 · House clinical team·Cockpit curated: 2026-05-19