What is Suprelorin®?

Suprelorin® is a resorbable contraceptive implant which is inserted under the skin between your dog’s shoulders. The implant softens quickly, causing no discomfort. After implant placement, an active ingredient is released steadily preventing the production of the sex hormones and testosterone. This results in temporary infertility. The implant needs to be repeated every 6 or 12 months (depending on implant size) to maintain its effect.

Suprelorin® Reversible infertility

Testosterone is generally reduced 2–3 weeks following implantation. It will take around 6 weeks for your dog to become infertile due to sperm which is stored in the reproductive tract. Infertility lasts for a minimum of 6 months (4.7mg implant) or a minimum of 12 months (9.4mg implant). Once the implant wears off the dog’s fertility will gradually return.

Return to fertility

Suprelorin® 6 month (4.7mg): In most cases testosterone levels return to normal 8–10 months post implantation, however it may take a small proportion of dogs 18 months or more. Viable sperm are produced approximately 8 weeks post recovery of normal testosterone levels.

Suprelorin12® 12 month (9.4mg): The majority of dogs return to normal testosterone levels by 2–2 1 /2 years post implantation however it may take a small proportion of dogs longer than 2 1 /2 years. Viable sperm are produced approximately 8 weeks post recovery of normal testosterone levels.

Should I expect to see any changes in my dog?

Your dog’s testicles may decrease in size (by approximately 1 /3) and may feel softer than normal. A decrease in testicle size is a good way to check if the implant is working.

Does the implant require removal?

No. The implant is resorbable and will disappear over time.

Aids in the control of benign prostatic enlargement

Implantation with Suprelorin® results in a decrease in prostatic size. Improvement of clinical signs may be expected from 1–2 weeks post implantation.

Aid in the control of testosterone related behaviours

Improvement in behaviours may be seen once testosterone levels have declined. Testosterone is generally reduced 2–3 weeks following implantation. It is important to remember that behaviour problems are not always due to testosterone and castration may not resolve the problem behaviour. Please contact your vet if you have any further questions about your dog’s treatment.

Important!

It is important that your dog is kept away from in season (on heat) female dogs for at least 6 weeks following initial implantation. This is because it takes around 6 weeks following implantation for the dog to become infertile and if he mates with a female dog during this time a pregnancy may result. Mating during implant effect (after 6 weeks post implantation) Some implanted males will still mate and may even tie with a female dog during the expected period of activity of a Suprelorin® implant, however, such matings should be infertile (no viable sperm should be produced by a male with a functioning implant still in place). Should a treated dog mate with a female dog, contact your vet so that appropriate measures can be taken to rule out the risk of pregnancy

Monitoring response

The dog can be monitored for a reduction in testicle size (size reduces by approximately 1 /3) following Suprelorin® implantation. Very occasionally an implant may fall out. If you are concerned that your dog has not responded to the implant then a testosterone assay may be taken 6 weeks after implantation to check for correct implantation. If you think your dog may not be responding to the implant please contact your vet. 

image from Virbac and www dot caninenaturalcures dot co dot uk

Copied from Virbac client handout