Altrenogest 150MG/ML for Equines

Altrenogest is used to suppress estrus in mares in order to facilitate induction of normal estrous cycle activity. It is also used in mares to synchronize scheduled breeding activity, thus improving breeding efficiency. In the suppression of estrous behavior in mares, this is usually related to mares that are used as performance horses.

Altrenogest is a progestin of the 19-nortestosterone group. As a veterinary medication, it is used extensively in the reproductive management of mares to control the reproductive cycle, help maintain pregnancy, and help with behavior modification. Altrenogest has been demonstrated to maintain pregnancy in oophorectomized mares and may be of benefit in mares that abort due to subtherapeutic progestin levels. 

Contraindications & Warnings

Since it has been determined that altrenogest can disrupt the hormonal activity of other species (such as humans) via contact, the use of protective gloves when handling altrenogest are recommended and that a physician be contacted immediately in the event of accidental contact. According to the available literature, altrenogest should not be handled by women of child-bearing age, and should not be administered to immature animals, animals with diabetes, uterine infection, a history of vaginal discharge or reproductive abnormalities, or animals where the owner or managers suspect they are pregnant.5

Labeling for altrenogest products includes extensive warnings against human exposure, as the hormone is readily absorbed through intact skin. Altrenogest is not approved for use in humans; the following list of exposure precautions is based upon the known effects of other progestins used in people on a chronic (long-term) basis.

People who should not handle altrenogest products include:

• Women who are or suspect they are pregnant.

• Anyone with thrombophlebitis or thromboembolic disorders or with a history of these events.

• Anyone with cerebral-vascular or coronary-artery disease.

• Women with known or suspected carcinoma of the breast.

• People with known or suspected estrogen-dependent neoplasia.

• Women with undiagnosed unexplained vaginal bleeding.

• People with benign or malignant tumors which developed during the use of oral contraceptives or other estrogen-containing products.

• Anyone with liver dysfunction or disease.

It is essential that people administering altrenogest products take appropriate precautions to prevent exposing themselves or others to this medication.6

Your veterinarian should be consulted before beginning any treatment regimen.

Where to buy Altrenogest

FOR RX ONLY: A valid prescription from a licensed veterinarian is required for dispensing this medication.

1Machnik M, et al. Pharmacokinetics of altrenogest in horses. J Vet Phamacol Ther. 2007;30:86-90.

3Baker TW, Davidson AF. Obstetrical Emergencies I.  Western Veterinary Conference 2012 2012. 2012.  

4Volkmann D. Rational Use of Progestagen Therapy During Pregnancy.  Western Veterinary Conference 2010 2010. 2010.  

5equi-med.com.

6Plumb’s Veterinary Drugs.

7Dascanio J. Hormonal Control of Reproduction.  Proceedings: ABVP 2009. 2009.  Veterinary Information Network.

8McCue P. Ovarian problems in the non-pregnant mare.  Proceedings: Western Veterinary Conference 2003. 2003.  Veterinary Information Network.

9Valla W. Medical management of mares with complicated pregnancies.  Proceedings: ACVIM Forum 2003. 2003.  Veterinary Information Network.

10Squires EL, et al. Clinical Applications of Progestins in Mares. Comp CE. 1983;5(1):S16-S22.