Aurora Pharmaceutical receives FDA approval on Altren®, an altrenogest oral progestin solution for horses.

Altren® (altrenogest) Solution 0.22% (2.2 mg/ml) is manufactured in Northfield Minnesota in an FDA licensed facility using the same formulation as Regu-Mate®.

Altren® (altrenogest) Solution 0.22% is indicated to suppress estrus in mares. Suppression of estrus allows for a predictable occurrence of estrus following drug withdrawal. Altren® (altrenogest) is administered orally at 1 mL per 110 pounds’ body weight (0.044 mg/kg) once daily for 15 consecutive days. Administer solution directly on the base of the mare’s tongue or on the mare’s usual grain ration.

Extensive clinical trials have demonstrated that estrus will be suppressed in approximately 95% of the mares within three days; however, the post-treatment response depended on the level of ovarian activity when treatment was initiated. Estrus in mares exhibiting regular estrus cycles during the breeding season will be suppressed during the treatment; these mares return to estrus four to five days following treatment and continue to cycle normally.

Talk with your veterinarian about the proper use and safe-handling of Altren®.

Altren® (altrenogest) Solution 0.22% is available in 1000ml plastic bottles along with a dispensing cap.

Aurora Pharmaceutical has supply agreements with most of the major distributors throughout the United States. Please check the website,, for the list and contact information.
If you would like more information, please contact Aurora customer service at 888-215-1256.