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Estradiol (Transdermal Patch)

HRTprescriptiontransdermal patch · inferred

Transdermal estradiol patch delivering 25-100 mcg/day. Bypasses first-pass hepatic metabolism, producing physiological estradiol:estrone ratios. Changed twice weekly (Vivelle-Dot, Climara) or weekly. Lower VTE risk than oral estrogen.

Projected serum levels — 50 mcg/day (≈ 0.050 mg), twice weekly

Estradiol (Transdermal Patch)
Estradiol (Transdermal Patch) modeled serum levels, 50 mcg/day (≈ 0.050 mg) twice weekly over 18 days Population-based pharmacokinetic estimate. Steady state reached after approximately 7 days. 0 0.25 0.50 0.75 1 Day 0 Day 4 Day 9 Day 13 Day 18 Time on a regular schedule ≈ steady state · day 7
Estradiol (Transdermal Patch) modeled serum levels with a loading dose of 61.6 mcg/day, then 50 mcg/day (≈ 0.050 mg) twice weekly The first dose is larger so levels approach steady state faster. 0 0.25 0.50 0.75 1 Day 0 Day 4 Day 9 Day 13 Day 18 Time on a regular schedule

Maintenance schedule: 50 mcg/day (≈ 0.050 mg) twice weekly (transdermal patch).

Loading schedule: 61.6 mcg/day on day 1, then 50 mcg/day (≈ 0.050 mg) twice weekly — reaching therapeutic levels sooner.

Modeled steady state after ~7 days: peak ≈ 0.001 mg, trough ≈ 0.000 mg body load. Population-based estimate over 18 days for a reference dose at a 70 kg reference body mass — the interactive app scales curves to your doses, timing, and body mass.

Key facts

Category
HRT
Route modeled
Transdermal patch
Model confidence
inferred
Half-life
1.5 h
Common dose
50 mcg/day (≈ 0.050 mg)
Suggested maximum
100 mcg/day/day
Reference dose range
25–100 mcg/day (single dose)
Suggested cadence
twice weekly
Validated against
0.10 mg td — Cmax 0.000 mg/L at 36 h

Documented interactions

  • danger
    Carbamazepine (Tegretol) + Estradiol (Transdermal Patch) CYP induction

    Carbamazepine (Tegretol) inducer of CYP3A4 predicted to change Estradiol (Transdermal Patch) AUC by ~0.32x

  • danger
    Efavirenz (Sustiva) + Estradiol (Transdermal Patch) CYP induction

    Efavirenz (Sustiva) inducer of CYP3A4 predicted to change Estradiol (Transdermal Patch) AUC by ~0.21x

  • danger
    Levothyroxine (Synthroid) + Estradiol (Transdermal Patch) Protein binding

    Estradiol (Transdermal Patch) may displace Levothyroxine (Synthroid) from plasma protein binding sites, transiently raising free drug concentration. This drug has a narrow therapeutic index; free…

  • danger
    Phenobarbital + Estradiol (Transdermal Patch) CYP induction

    Phenobarbital inducer of CYP3A4 predicted to change Estradiol (Transdermal Patch) AUC by ~0.49x

  • danger
    Phenytoin (Dilantin) + Estradiol (Transdermal Patch) CYP induction

    Phenytoin (Dilantin) inducer of CYP3A4 predicted to change Estradiol (Transdermal Patch) AUC by ~0.49x

  • danger
    Rifampin + Estradiol (Transdermal Patch) CYP induction

    Rifampin inducer of CYP3A4 predicted to change Estradiol (Transdermal Patch) AUC by ~0.21x

Serum checks 251 modeled interaction pairings for estradiol (transdermal patch) across your whole stack — absorption conflicts, enzyme inhibition, and nutrient depletion included.

Research behind this entry

  1. Transdermal Estradiol for the Prevention of Osteoporosis Lufkin EG et al. · New England Journal of Medicine, 1992 DOI

    RCT establishing transdermal estradiol efficacy for osteoporosis prevention in postmenopausal women with favorable safety profile.

  2. Venous Thromboembolism in Relation to Oral Contraceptive and Hormone Replacement Therapy Use Canonico M et al. · European Journal of Obstetrics & Gynecology, 2010 DOI

    Meta-analysis showing transdermal estrogen does NOT increase VTE risk, unlike oral estrogen which doubles it — supporting transdermal as the safer HRT route.

  3. Transdermal Versus Oral Estrogen Therapy and Vascular Events Sweetland S et al. · Lancet, 2019 DOI

    Million Women Study analysis confirming transdermal HRT associated with significantly lower VTE and stroke risk compared to oral formulations.

3 published studies referenced in the app, each with a plain-language summary.