» Rat Guide     » Health Guide     » Care Guide     » Medication Guide     » Breeding Guide    

Tardak / Delmadinone Acetate

Back to Hormones


(VR Tardak Androgen Inhibitive Suspension)
(Drug Manufacturers: Jurox Pty Ltd, Pfizer )


Suspension: 10 mg/mL
Availability primarily outside of U.S.


Delmadinone acetate is an antiandrogen having a greater effect than progesterone in its ability to affect testosterone production by restraining interstitial cell function. Its result is to decrease hypersexual behavior or libido.

Antiandrogens are believed to have two modes of action:
1. inhibit pituitary gonadotrophin release and,
2. effecting a behavioral sex center.

Tardak’s effects are known to be reversible when the medication is stopped.


Used for aggressiveness and or nervousness in bucks as a form of temporary chemical castration, or as a determinate to whether surgical castration is an option to control aggressive behavior.

Drug Interactions or Contraindications

Caution should be used when combining with other types of steroid therapy.

Adverse Reactions

None reported at this time.

Dosage Recommendations

While not licensed for rats, the Pfizer drug company advised that it could be used at the same dose rate and indication as for male dogs and cats:- i.e. 0.1 mL subcutaneous for average 500g rat, and can be repeated 10 days after the first injection if not apparently working or as needed - possibly after 3 - 4 weeks if desired effect wears off. (Additional veterinarian reference of dose use:17)
VET SHOULD FOLLOW INSTRUCTIONS AS ON DATA SHEET. Main indications are for certain forms of aggressiveness and nervousness in male rats. (A form of chemical castration.)

NB Changes in coat color may occur so if this could be a problem e.g. in showing animals other areas of injection may need to be considered.


  • Store in cool (25 degrees or less) are away from light.
  • Shake well prior to dosing.
  • Response to drug may not be seen the same day.
  • *Note: male rats remain fertile while on drug even though libido/sexual aggression is diminished.

Posted on February 6, 2005, 16:56, Last updated on December 24, 2008, 12:48 | Hormones

Rat Guide Logo
All other written and visual materials used by permission of specific authors for the sole use of the Rat Guide.
Brought to you by KuddlyKorner4u
See Logos page for linking to the Rat Guide.
Rat Guide brought to you by KuddlyKorner4u