Non-Surgical Alternative to Castration

 World's First Pet Contraceptive

A new contraceptive implant for canines offers the advantages of castration without surgery. 
Now available in commercial quantities in Australia and New Zealand, Suprelorin, the world's first pet contraceptive, is implanted under the skin between the shoulders to reduce a male dog's testosterone levels to zero and cease reproductive function for six months. Inserted with an implanter similar to those used for micro-chipping, Suprelorin slowly releases deslorelin, a hormone similar to those used to treat human prostate cancer. The low, continuous dose of deslorelin prevents the produc­tion of sex hormones. The biocompatible implant disappears over time.

Soon pet owners may be able to prevent their male dogs from breeding without castrating them thanks to Suprelorin, a canine birth control implant developed in Australia. "Some male owners, particularly those with 'macho' breeds of dogs, are not keen to castrate their pets," said Dr. Tim Trigg, managing director for Peptech Animal Health (Sydney, Australia), which markets Suprelorin.

"A quick and easy implant gives them a more humane, cost-effective choice that leaves their dogs intact but is equally efficacious. The same benefits apply to dogs being shown, of course." In addition to preventing reproduction, the implant treats testosterone related behavioural problems.

It also is approved to treat benign prostatic hyperplasia, a non cancerous enlargement of the prostate gland common in older dogs that have not been neutered.

Trials show Suprelorin is also effective in controlling populations of Elephants, Lions, Cheetahs, Monkeys, Dolphins, Seals, Koalas and Kangaroos.

Suprelorin is a non-surgical alternative to castration that delivers male dogs all the contraceptive, health and behavioural benefits of castration. The slow-release product stops the hormones that cause testosterone production. This means that: 

  1. fertility is controlled and ejaculation stopped;

  2. painful prostate problems, particularly common in older dogs, can be treated; and

  3. anti-social behaviour such as sexual aggression or wandering is prevented

All these benefits occur without having to resort to surgery, which requires an anaesthetic and a recovery period. 

The retail cost: about $60 a dose, compared to between $150 to $300 estimated for castration. The implant is effective for at least six months. 

Trials with more than 500 dogs over eight years have shown no side effects. 

The implanter is like the one used to implant microchips. As a treatment for prostate problems, Suprelorin is unique in the market because it lasts for six months without the owners having to come back for additional treatment. 

Reasons not to castrate 
The implant is more humane than surgery; many dog owners, particularly men and or for cultural reasons would prefer to leave their dogs intact; 'show' dogs also need to be intact for shows; and people may want to breed their dog later on (fertility is shown to return after treatment stops) but might be having behavioural issues for the first few years

Suprelorin, manufactured by Peptech Animal Health, is an Australian invention. The company has patented the material in the implant that allows the active ingredient to release slowly over time. The small implant (12mm long and 2.3mm thick) does not have to be removed - it softens and dissolves over time.

Desexing is not reversible and the perfect age is six months.

Future Indications:

  • Use in females for fertility control

  • Use in hormone responsive incontinence

  • Use in other species (population control) - ongoing


Alternative treatment now available...
A new slow released implant called Suprelorin has shown great promise in the management of incontinence in desexed female dogs. 
Suprelorin reduces elevated levels of circulating female hormones (FSH and LH), 
a phenomenon seen in desexed female dogs.
Reduction of FSH and LH has been shown to have high success rates in treating urinary incontinence. Duration of the response ranges from 21-365 days with an average of 159 days.

In those case where Suprelorin did not completely resolve the incontinence, the addition of Propalin to the regime was successful.

Status of Current Approaches

ACC&D’s Priorities for Non-Surgical Products for Pet Population Control:

  • Approved by regulatory agencies as safe (for animals and for the humans administering) and effective.
  • Permanent. Though there may be some opportunity for long term (3+ years) products.
  • Deliverable in a single injection or treatment.
  • Product/s available for effective use in both male and female, dogs and cats.
  • Documented effects on behavior and health.
  • Can be provided at affordable rates for use in indigent or low-income client populations.

Below we’ve included brief descriptions of some of the more promising approaches. For a more thorough review of recent research, please see the Proceedings of the Third International Symposium on Non-Surgical Contraceptive Methods of Pet Population Control.

Product: ChemSpay®
From: Senestech
Status: Early stage development (dose levels, formulation) in dogs. Preliminary work in cats.
What it is: An industrial chemical that has been shown to deplete the ovarian follicles and cause sterility in rodents. Some preliminary data showing this effect is also seen in dogs.
ACC&D Perspective: While this approach is in the very early stages of development, we believe it shows promise for meeting our priorities for non-surgical sterilization products. ACC&D has provided funding for one Senestech study and is in discussions with Senestech regarding further collaboration.
For More Information: Review materials from Dr. Loretta Mayer’s presentation on ChemSpay at the 2006 ACC&D Symposium.

Product: Suprelorin®
From: Peptech Animal Health
Status: Approved and available for use in male dogs in Australia (6 month and 12 month doses) since December 2004 and New Zealand (6 month dose only) since September 2005. Received EU regulatory approval March 2007 and hopes to make the product available in Europe in the second half of 2007. Peptech has announced plans to seek approval for future global use.
What it is: A deslorin (GnRH agonist) implant for male dogs resulting in sterility for six or 12 months (both durations available).
ACC&D Perspective: Because Suprelorin is not permanent, it is not an ideal product for population control. However, we believe Suprelorin may have potential to fill a niche in certain cases. We are also interested to see if new formulations might be developed to provide longer term contraception.
For more information: Visit Peptech Animal Health’s web site and read ACC&D's interview with Peptech's Paul Schober.  

Product: Neutersol®
From: Abbott Laboratories
Status: Neutersol is approved by the FDA for use in the US. Neutersol is currently unavailable, however the patent holder announced in November 2006 that they are working with Abbott Laboratories, which will be manufacturing and distributing the product in the U.S. in the “near future”. A release date is not yet available.
What it is: Neutersol is an intratesticular injection of zinc gluconate neutralized by arginine. Neutersol is approved by the FDA for use in male dogs from 3-10 months of age, though it has been shown to be safe and effective for adult dogs through off-label use. Neutersol may be approved for use in male cats in the future.
ACC&D Perspective: Zinc gluconate (brand name: Neutersol®) is the only non-surgical pet sterilant approved as safe and effective for use in the US. Zinc gluconate is cheaper and easier to administer than surgical sterilization is to perform. A 10,000 dog study in Mexico has demonstrated both safety and effectiveness in adult dogs and in large field programs. ACC&D believes that zinc gluconate is a promising international tool for population control.
For More Information: Read the proceedings from the Neutersol session at ACC&D's Third International Symposium

Product: Gonazon®
From: Invervet France
Status: Received regulatory approval in November 2006 in the European Union.
What it is: The active ingredient, azagly-nafarelin, is a GnRH agonist. A silicone implant provides one-year reversible contraception for female and male dogs and cats.
ACC&D Perspective: While this does not fit the profile of a permanent tool for population management programs, Dr. Driancourt announced some limited data in cats showing that when the implant is not removed, queens had suppression of estrus over an extended period of time – nearly three years so far. This raises the possibility that the product might be useful in the control of feral cat populations, although the expense involved in manufacturing GnRH agonists may be a limiting factor.
For More Information: Review materials from Dr. Marc-Antoine Driancourt’s presentation on Gonazon at the 2006 ACC&D Symposium.

Product: GonaCon
From: National Wildlife Research Center of the USDA
Status: Data is being submitted to the EPA initially for approval for use in deer and other cervids. Separate studies underway assess potential for use in dogs and feral cats.
What it is: A GnRH vaccine developed and tested for use in several wildlife species, and the basis for a vaccine being assessed for use in cats.
ACC&D Perspective: GonaCon has been shown (in preliminary research) to be effective in approximately 75% of female cats for 2 and ½ years to date.. Because GonaCon is assumed to not be permanent and is not effective in 100% of animals, it is not ideal. However, we believe GonaCon may have potential to fill a niche in feral cat colony management.
For More Information: Review materials from Dr. Kathleen Fagerstone's and Dr. Gary Killian's presentations at the 2006 ACC&D Symposium.

Product: Canine Gonadotropin Releasing Factor Immunotherapeutic
From: Pfizer Animal Health
Status: Has received conditional approval from the FDA. (Available now.)
What it is: A GnRH vaccine developed and marketed for treatment of benign prostatic hyperplasia (BPH), a common health problem in post-pubescent, intact male dogs. While not labeled for use as a contraceptive, a side effect of the treatment is contraception and a reduction or elimination of testosterone-related behaviors. Administered via subcutaneous injection. Repeated every six months.
ACC&D Perspective: While this treatment does not meet our priority of being permanent or long-term, we are excited to see the first GnRH vaccine approved for use in dogs in the U.S. We believe there may be some potential niche use for this product.
For More Information: Click here to read the product profile from Pfizer.

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