Dog - Deslorelin
Why has my veterinary surgeon prescribed this medicine?
Deslorelin is used in healthy sexually mature entire male dogs to make them temporarily infertile.
How does this medicine work?
Deslorelin acts like the natural gonadotrophin-releasing hormone, which controls the secretion of hormones involved in fertility. It blocks the production of follicle-stimulating hormone and luteinising hormone (FSH and LH). This results in a reduced level of testosterone in the blood, sperm production stops and libido is reduced. Your dog will be infertile about 6 weeks after implantation. Treated dogs should be kept away from bitches in oestrus (heat, season) until at least 6 weeks after implantation. A continuous low dose of deslorelin is slowly released from the implant over six months.
How do I give this medication?
Your veterinary surgeon will insert the implant under your dog’s skin on the back between the lower neck and the lumbar area.
The implant is effective for about six months. A new implant can be administered after six months and this is immediately effective.
Potential side effects
- Your pet will be infertile while the implant is effective and for about one year after the last treatment. Thereafter, testosterone levels and semen characteristics will return to normal and fertile mating is possible.
- Side effects include swelling and inflammation at the implantation site.
- Other side effects include decreased size of testicles during treatment and rarely a testicle may ascend (rise up) into the abdomen.
- This medication should not be used in dogs that have not reached puberty.
- Your dog’s libido is reduced during treatment but other behavioural changes such as male-associated aggression may not be affected.
Possible drug interactions
- Make sure to tell your veterinary surgeon what other medication you are giving to your pet.
- Contact your veterinary surgeon if your pet experiences any unusual reactions when different medications are given together.
© Copyright 2025 LifeLearn Inc. Used and/or modified with permission under license. This content written by LifeLearn Animal Health (LifeLearn Inc.) is licensed to this practice for the personal use of our clients. Any copying, printing or further distribution is prohibited without the express written consent of LifeLearn. This content does not contain all available information for any referenced medications and has not been reviewed by the FDA Center for Veterinary Medicine, or Health Canada Veterinary Drugs Directorate. This content may help answer commonly asked questions, but is not a substitute for medical advice, or a proper consultation and/or clinical examination of your pet by a veterinarian. Please contact your veterinarian if you have any questions or concerns about your pet’s health. Created on Apr 28, 2009.
