Chemical Castration

Chemical Castration in Dogs – Suprelorin Implants 

What does this mean?

Traditionally, surgical castration of dogs has been seen as a standard way to prevent unwanted mating and to reduce the risk of a number of medical conditions (testicular cancer, prostate disease). Recent research shows that around 25% of pet owners have a degree of concern regarding surgically castrating their pet.

Chemical castration can provide a short term solution to those owners who want to see the effects of castration on their pets before going ahead surgically, or as an ongoing management for those who do not want to proceed with a surgical approach.

Infertility is achieved from 6 weeks up to at least 6 months after initial treatment. Treated dogs should therefore still be kept away from bitches on heat within the first six weeks after initial treatment.

What is a Suprelorin implant?

The Suprelorin implant is a slow release hormone implant around the size of a microchip. The implant is inserted under the loose skin on the back between the lower neck and the back. This can be done without sedation and during a routine consultation appointment.

Suprelorin effects can be seen at about six weeks in dogs and can last for 6 or 12 months depending on the size of the implant. If the effect is successful, the implant can be repeated.

The suprelorin implant works by managing to mimic castration. It does this by impersonating the naturally occurring hormone gonadotropin. After an initial increase or ‘flare up’ of two important hormones LH and FSH, in response to Superlorin, the gland which controls the production of these hormones becomes ‘desensitised’ and effectively ‘gives up’. This in turn causes the production of testosterone to fall significantly. As a result the dog stops producing sperm.

Which dogs can have an implant?

It is used in healthy, sexually mature dogs who have not been neutered to make them temporarily infertile.

Are there any side effects?

Moderate swelling at the implant site may be observed for 14 days. Histologically, mild local reactions with chronic inflammation of the connective tissue and some capsule formation and collagen deposition have been seen at 3 months after administration.

A significant decrease in testicle size will be seen during the treatment period. In very rare cases, a testicle may be able to ascend through the groin.

In very rare cases (<0.01%) there has been transitory increased sexual interest, increased testicle size and testicular pain immediately after implantation. These signs were resolved without treatment.

During the treatment period, rare clinical effects (> 0.01% to < 0.1%) have been reported: hair coat disorders (e.g. hair loss, alopecia, hair modification), urinary incontinence, down-regulation associated signs (e.g. decrease in testicle size, reduced activity).

In very rare cases (<0.01%), a transient behavioural change has been reported with the development of aggression.

Surgical or medical castration might have unexpected consequences (i.e. improvement or worsening) on aggressive behaviour. Thus, dogs with sociopathic disorders and showing episodes of intra-specific (dog to dog) and/or inter-specific (dog to another species) aggressions should not be castrated either surgically or with the implant. If you are concerned, we can assist you with behavioural referrals and support.

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