Estradiol

hormone · endocrine · reproductive · Oral · Transdermal · Intramuscular · Subcutaneous

Estradiol, a hormone. Primary endogenous estrogen. Activates ER-α and ER-β nuclear receptors → transcriptional regulation. Also rapid non-genomic… Oral half-life 14 h.

Primary endogenous estrogen. Activates ER-α and ER-β nuclear receptors → transcriptional regulation. Also rapid non-genomic membrane signaling. Therapeutic in menopausal HRT, gender-affirming care, and certain cancers (oral, transdermal, IM ester forms).

DOSE CORRECTED FROM A DELIVERY RATE STORED AS AN ABSOLUTE DOSE. The TD block read {"min":0.025,"max":0.1,"typical":0.05,"unit":"mg"}, which is the patch's mg/day strength, not the amount it delivers. This row already stores zo_dur_hr, so the wear interval was on the record while the dose contradicted it. Label verbatim: "Start therapy with Climara 0.025 mg per day applied to the skin once weekly". Delivered over the interval that gives 0.175-0.7 mg, typical 0.35 mg — ARITHMETIC, rate x interval. Source: Climara (estradiol) patch, DailyMed set id 1e9702c4-f2d7-4ea8-b6e8-7dca31671864, v25 published 2026-03-30. The once-weekly wear matches the 168 h zero-order duration already on the row, so the patch really does deliver seven daily portions per application. The 0.025 mg/day the label names as the STARTING dose is the stored minimum. THE CATALOG ALREADY DID THIS RIGHT ELSEWHERE, which is how the defect was spotted: nicotine stores 7-21 mg against a 24 h duration and rivastigmine 4.6-13.3 mg against 24 h, both being what the patch delivers over that interval rather than its hourly rate. PK: THE STORED ABSORPTION RATE WAS THE SOLVER DEFAULT WEARING A CITATION. A ka of 1.0/h is exactly what resolvePk substitutes when the field is ABSENT, and no source on this record states one. Removing it is NUMERICALLY A NO-OP — the resolver supplies the identical number — so no curve moves; what changes is that the record stops asserting an absorption rate it never measured. This is the same shape already found on a volume of 35 L, which is likewise the default at the seventy-kilogram reference. THE WIDER DEBT IS LEFT ALONE ON PURPOSE: twelve values account for 152 of the 276 authored absorption rates, but the other eleven are NOT the default, so deleting those would move their curves rather than leave them, which is the error this audit spent a batch documenting.

Pharmacokinetics

• Oral — t½ 14 h · F 5% · Vd 1000 L
• Transdermal — t½ 14 h · F 100% · Vd 1000 L

Sources: PMID:9048584, PMID:4039300