Estriol (medication)

This article is about estriol as a medication. For its role as a hormone, see Estriol.
Estriol (medication)
Clinical data
Pronunciation/ˈɛstriɒl, -traɪɒl/[1]
ESS-TREE-ohl[1]
Trade namesOvestin, others[2][3]
Other namesOestriol; E3; 16α-Hydroxyestradiol; Estra-1,3,5(10)-triene-3,16α,17β-triol
Routes of
administration		By mouth, vaginal, intramuscular injection[4][5][6]
Drug classEstrogen
ATC code
Legal status
Legal status
  • In general: ℞ (Prescription only)
Pharmacokinetic data
BioavailabilityOral: ~1–2%[4][6]
Vaginal: ~10–20%[5][4][6]
Protein binding92%:[4]
• Albumin: 91%[4]
• SHBGTooltip Sex hormone-binding globulin: 1%[4]
• Free: 8%[4]
MetabolismLiver, intestines (conjugation (glucuronidation, sulfation), oxidation, hydroxylation)[4]
Metabolites• Estriol 16α-glucuronide[7][5]
• Estriol 3-glucuronide[7][5]
• Estriol 3-sulfate[7][5]
• Estriol 3-sulfate 16α-gluc.[7][5]
• 16α-Hydroxyestrone[4][8]
• Others (minor)[4]
Elimination half-lifeOral: 5–10 hours[9][8]
IMTooltip Intramuscular injection: 1.5–5.3 hours (as E3)[5]
IVTooltip Intravenous injection: 20 minutes (as E3)[10][11]
ExcretionUrine: >95% (as conjugates)[4][5]
Identifiers
  • (8R,9S,13S,14S,16R,17R)-13-methyl-6,7,8,9,11,12,14,15,16,17-decahydrocyclopenta[a]phenanthrene-3,16,17-triol
CAS Number
PubChem CID
IUPHAR/BPS
DrugBank
ChemSpider
UNII
KEGG
ChEBI
ChEMBL
Chemical and physical data
FormulaC18H24O3
Molar mass288.387 g·mol−1
3D model (JSmol)
Melting point82 to 86 °C (180 to 187 °F) (experimental)
Solubility in water0.119 mg/mL (20 °C)
  • Oc1cc3c(cc1)[C@H]2CC[C@@]4([C@@H](O)[C@H](O)C[C@H]4[C@@H]2CC3)C
  • InChI=1S/C18H24O3/c1-18-7-6-13-12-5-3-11(19)8-10(12)2-4-14(13)15(18)9-16(20)17(18)21/h3,5,8,13-17,19-21H,2,4,6-7,9H2,1H3/t13-,14-,15+,16-,17+,18+/m1/s1 checkY
  • Key:PROQIPRRNZUXQM-ZXXIGWHRSA-N checkY
  (verify)

Estriol (E3), sold under the brand name Ovestin among others, is an estrogen medication and naturally occurring steroid hormone which is used in menopausal hormone therapy.[12][4][6][13] It is also used in veterinary medicine as Incurin to treat urinary incontinence due to estrogen deficiency in dogs.[14][15][16][17] The medication is taken by mouth in the form of tablets, as a cream that is applied to the skin, as a cream or pessary that is applied in the vagina, and by injection into muscle.[4][5][6]

Estriol is well-tolerated and produces relatively few adverse effects.[12][18] Side effects may include breast tenderness, vaginal discomfort and discharge, and endometrial hyperplasia.[12][18] Estriol is a naturally occurring and bioidentical estrogen, or an agonist of the estrogen receptor, the biological target of estrogens like endogenous estradiol.[4] It is an atypical and relatively weak estrogen, with much lower potency than estradiol.[4][6][19] When present continuously at adequate concentrations however, estriol produces full estrogenic effects similarly to estradiol.[20][21]

Estriol was first discovered in 1930,[22][23] and was introduced for medical use shortly thereafter.[24][25] Estriol esters such as estriol succinate are also used.[4][18][3] Although it is less commonly employed than other estrogens like estradiol and conjugated estrogens, estriol is widely available for medical use in Europe and elsewhere throughout the world.[4][2][3][6]

  1. ^ a b Estriol. Dictionary.com.
  2. ^ a b Cite error: The named reference IndexNominum2000 was invoked but never defined (see the help page).
  3. ^ a b c Cite error: The named reference Drugs.com was invoked but never defined (see the help page).
  4. ^ a b c d e f g h i j k l m n o p q Kuhl H (August 2005). "Pharmacology of estrogens and progestogens: influence of different routes of administration". Climacteric. 8 (Suppl 1): 3–63. doi:10.1080/13697130500148875. PMID 16112947. S2CID 24616324.
  5. ^ a b c d e f g h i Cite error: The named reference OettelSchillinger2012 was invoked but never defined (see the help page).
  6. ^ a b c d e f g Taylor M (December 2001). "Unconventional estrogens: estriol, biest, and triest". Clinical Obstetrics and Gynecology. 44 (4): 864–879. doi:10.1097/00003081-200112000-00024. PMID 11600867. S2CID 27098486.
  7. ^ a b c d Cite error: The named reference MuseyKirdani1973 was invoked but never defined (see the help page).
  8. ^ a b Dörwald FZ (4 February 2013). "Steroids". Lead Optimization for Medicinal Chemists: Pharmacokinetic Properties of Functional Groups and Organic Compounds. John Wiley & Sons. pp. 486–. ISBN 978-3-527-64565-7.
  9. ^ Wentz AC (January 1988). Gynecologic Endocrinology and Infertility for the House Officer. Williams & Wilkins. ISBN 978-0-683-08931-8. Estriol is considered a short-acting estrogen with a half-life of 5 hours.
  10. ^ Visser M, Holinka CF, Coelingh Bennink HJ (2008). "First human exposure to exogenous single-dose oral estetrol in early postmenopausal women". Climacteric. 11 (Suppl 1): 31–40. doi:10.1080/13697130802056511. PMID 18464021. S2CID 23568599.
  11. ^ Applied Biochemistry of Clinical Disorders (2nd ed.). University of California. 1986. ISBN 978-0-397-50768-9. Because its half-life is about 20 minutes, unconjugated estriol rapidly reflects changes in estriol production.
  12. ^ a b c Rueda C, Osorio AM, Avellaneda AC, Pinzón CE, Restrepo OI (August 2017). "The efficacy and safety of estriol to treat vulvovaginal atrophy in postmenopausal women: a systematic literature review". Climacteric. 20 (4): 321–330. doi:10.1080/13697137.2017.1329291. PMID 28622049. S2CID 407950.
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  14. ^ Cite error: The named reference EttingerFeldman2017 was invoked but never defined (see the help page).
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  16. ^ Cite error: The named reference BonaguraTwedt2008 was invoked but never defined (see the help page).
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  18. ^ a b c Cite error: The named reference pmid28375935 was invoked but never defined (see the help page).
  19. ^ Cite error: The named reference Becker2001 was invoked but never defined (see the help page).
  20. ^ Cite error: The named reference pmid6356176a was invoked but never defined (see the help page).
  21. ^ Cite error: The named reference Clark_1984 was invoked but never defined (see the help page).
  22. ^ Cite error: The named reference Josimovich2013 was invoked but never defined (see the help page).
  23. ^ Cite error: The named reference SartorelliJohns2013 was invoked but never defined (see the help page).
  24. ^ Cite error: The named reference pmid13567043 was invoked but never defined (see the help page).
  25. ^ Cite error: The named reference pmid18744783 was invoked but never defined (see the help page).