Felis ISSN 2398-2950


Synonym(s): RU 534

Contributor(s): Monica Ptaszynska, Vetstream Ltd



  • Aglepristone.

Class of drug

  • Progesterone receptor antagonist.


Chemical name

  • (8S,11R,13S,14S,17R)-11-(4-dimethylaminophenyl)-17-hydroxy-13-methyl-17-[(Z)-prop-1-enyl]-1,2,6,7,8,11,12,14,15,16-decahydrocyclopenta[a]phenanthren-3-one

Molecular formula

  • C29H37NO2

Molecular weight

  • 431.60958

Physical properties

  • Clear yellow oily solution.

Storage requirements

  • Shelf life of 3 years.
  • Once opened must be used within 28 days and discarded if discoloration occurs.
  • As the available veterinary formulation contains no antibacterial preservative, swab the opening's membrane with suitable disinfectant each time before withdrawing the dose to be administered.
  • Protect the bottle from light.


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  • Pregnancy termination in female dogs.
    Not licensed for use in the cat.
  • Literature evidence indicates high efficacy for pregnancy termination in female cats when administered between 5 and 30 days of mating and lower efficacy when used before the end of estrus or after 45 d of pregnancy.
  • Literature evidence indicates that aglepristone is efficacious as a treatment of progestagen-dependent mammary fibroadenomatous hyperplasia (fibroadenomatosis) in queens   Mammary hyperplasia  .


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with other drugs

  • No data on interaction with other drugs in cats is available, however in dogs it is recommended to avoid the use with ketoconazole   Ketoconazole  , itraconazole   Itraconazole   and erythromycin   Erythromycin   as interaction may occur. In dogs, aglepristone may reduce the effect of glucocorticoid treatment.

with diagnostic tests

  • No data is available on the effect of the treatment on basic hematological and metabolic indices in cats. Hematological and biochemical changes (urea, creatinine, chloride, potassium, sodium, ALT, ALP, AST) reported in up to 5% of dogs following injection Blood biochemistry: overview.

Adverse Reactions

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Further Reading


Refereed papers

  • Recent references from PubMed nd VetMedResource.
  • Georgiev P, Bostedt H, Goericke-Pesch S, Dimitrov M, Petkov P, Stojanthev K, Tsoneva V, Wehrend A (2010) Induction of abortion with aglepristone in cats on day 45 and 46 after mating. Reprod Domest Anim 45(5), e161-167 PubMed.
  • Goericke-Pesch S, Plamen,  Georgiev P (2010) Prevention of pregnancy in cats using aglepristone on days 5 and 6 after mating. Theriogenology 74(2), 304-310 PubMed.
  • Jurka P, Max A (2009)Treatment of fibroadenomatosis in 14 cats with aglepristone - changes in blood parameters and follow-up. Vet Rec 165(22), 657-660 PubMed.
  • Nak D, Nak Y, Tuna B (2009) Follow-up examinations after medical treatment of pyometra in cats with the progesterone-antagonist aglepristone. JFMS 11(6), 499-502PubMed.
  • Favre R N, Gimenez F, Stornelli M C, Tittarelli C M, Savignone C A, de la Sota R L, Sternelli M A (2007) Induction of abortion in queens by administration of aglepristone (Alizin): Preliminary results. Theriogenology 68, 492-518; abstr.014.
  • Fieni F, Martal J, Marnet P G, Siliart B, Guittot F (2006) Clinical, biological and hormonal study of mid-pregnancy termination in cats with aglepristone. Theriogenology 66(6-7), 1721-1728. Epub 2006 Mar 24. Erratum in:Theriogenology 67(7), 1305 PubMed.
  • Georgiev P, Wehrend A (2006)Mid-gestation pregnancy termination by the progesterone antagonist aglepristone in queens.Theriogenology65(7), 1401-1406PubMed.
  • Georgiev P, Wehrend A, Dimitrov M, Vasilev N, Yotov S, Bostedt H (2006) Effect of progesterone receptor antagaonist aglepristone administered on days 5 and 6 after mating in queens.Reprod Domest Anim41(Suppl 1), 1-41 (abstr).
  • Meisl D, Hubler M, Arnols S (2003) Treatment of fibroepithelial hyperplasia (FEH) of the mammary gland in the cat with progesterone antagonist aglepristone (Alizine). Schweiz Arch Tierheilkd 145(3), 130-136 PubMed.
  • Goerlinger S, Kooistra H S, van den Broek A, Okkens A C (2002) Treatment of fibroadenomatous hyperplasia in cats with aglepristone. J Vet Intern Med 16(6), 710-713.
  • Wehrend A, Hospes R, Gruber A D (2001)Treatment of feline mammary fibroadenomatous hyperplasia with a progesterone-antagonist. Vet Rec148(11), 346-347 PubMed.

Other sources of information

  • BSAVA Small Animal Formulary. Ramsey I (2017) 9th edn.