Suprelorin® is a subcutaneous implant placed beneath the skin between the shoulders that releases a slow and continuous dose of deslorelin, a gonadotropin-releasing hormone (GnRH) analog. Deslorelin suppresses the reproductive endocrine system by preventing the production of pituitary hormones. This can alter behaviors associated with sex hormones for the implant’s duration of efficacy.

Originally developed in Australia, Suprelorin is currently marketed by Virbac and has received regulatory approval in nearly 50 countries, shown on the map below. (Note: in some of these countries Suprelorin has not yet been commercialized, but a veterinarian can obtain it by contacting their local Virbac team.)

Suprelorin was first approved and marketed in 2007 for contraception in male dogs. Regulatory approval of Suprelorin for fertility suppression has since expanded to include male cats and prepubertal female dogs, as well as ferrets.

Suprelorin is available in two doses for male dogs (4.7mg and 9.4mg, which are designed to be effective for a minimum of 6 and 12 months, respectively). It is available in the 4.7mg dose for male cats and prepubertal female dogs.

MALE DOGS

Suprelorin is labeled to induce temporary infertility in healthy, intact, sexually mature male dogs. So long as deslorelin is being released, the dog remains infertile and behaves as if castrated. (Note, however, that the manufacturer reports that it will generally take 2-3 weeks after implantation for testosterone to be reduced, and about 6 weeks for the dog to become infertile).

PREPUBERTAL FEMALE DOGS

Suprelorin is labeled to induce temporary infertility to delay the first estrus and heat signs in female dogs, and to prevent pregnancy at a young age. When used in females, it is advised that the implant be administered between 12 and 16 weeks of age.

Suprelorin mimics GnRH, which means it initially stimulates release of pituitary hormones. Consequently, if Suprelorin is administered after a female dog has reached sexual maturity, it can induce estrus. Though transient and soon followed by long-term hormonal suppression, it is possible that animals could become pregnant during this estrus. Administering to a prepubertal female avoids this potential issue.

MALE CATS

Suprelorin is labeled to induce temporary infertility and suppress both urine odor and sexual behaviors (libido, vocalization, urine marking, aggression) in intact male cats aged 3 months and older.

WHO MIGHT CONSIDER ITS USE? 

ACC&D believes that Suprelorin offers value for a variety of animals and circumstances. Among male dogs and cats, it is an option for those who cannot safely undergo surgery, and those whose guardians wish to prevent fertility without surgical sterilization (if treated with sequential implants). Some owners might wish to “trial” castration to ensure that it does not affect a dog’s working, herding, or hunting drive. 

For both males and females, Suprelorin is an excellent option for animals who are possible candidates for breeding, and whose guardians wish to delay a first litter in order to conduct health evaluations, and to not worry about the possibility of a surprise pregnancy or impregnation. Numerous studies have found that in males, the fertility suppression effect of Suprelorin is reversible, even after up to four consecutive implants.