Clinical particulars
Target species
Dogs (male)
Indications for use
For the induction of temporary infertility in healthy, entire, sexually mature male dogs
Contra-indications
None
Special warnings for each target species
Infertility is achieved from 8 weeks up to at least 12 months after initial treatment. Treated dogs should therefore still be kept away from bitches on heat within the first 8 weeks after initial treatment.
In 2 out of 30 dogs in the clinical trial infertility was not achieved until approximately 12 weeks after initial treatment, but in most cases these animals are not capable of successfully siring offspring.
Should a treated dog mate with a bitch between 8 and 12 weeks after treatment, appropriate measures should be taken to rule out the risk of pregnancy.
Any mating that occurs more than 12 months after the administration of Suprelorin may result in pregnancy. However, it is not necessary to keep bitches away from treated dogs following subsequent implantations for the initial 8 week period, provided that the veterinary medicinal product is administered every 12 months.
In certain cases, the implant may be lost from a treated dog. If loss of the implant is suspected in connection with the first implantation, this can be confirmed by observing no reduction in scrotal circumference or plasma testosterone levels after 8 weeks from the suspected date of loss, as both should reduce under correct implantation. If loss of the implant is suspected following re-implantation after 12 months, a progressive increase will be seen in scrotal circumference and/or plasma testosterone levels. In both of these circumstances a replacement implant should be administered.
The ability of dogs to sire offspring following their return to normal plasma testosterone levels, after the administration of the veterinary medicinal product, has not been investigated.
With respect to testosterone levels (an established surrogate marker of fertility), during clinical trials 68 % of dogs administered one implant, returned to fertility within 2 years of implantation. 95% of dogs had returned to normal plasma testosterone levels within 2.5 years of implantation. However, data demonstrating the complete reversibility of clinical effects (reduced testicular size, reduced ejaculation volume, reduced sperm count and reduced libido) including fertility after 12 months, or repeated implantation, are limited.
Due to limited data, the use of Suprelorin in dogs of less than 10 kg or more than 40 kg bodyweight should be subject to a risk/benefit assessment performed by the veterinarian. During clinical trials with Suprelorin 4.7 mg, the mean duration of testosterone suppression was 1.5 times longer among smaller size dogs (<10 kg) compared with all larger dogs.
Special precautions for use
Special precautions for use in animals
The use of Suprelorin in pre-pubertal dogs has not been investigated. It is therefore recommended that dogs should be allowed to reach puberty before treatment with the veterinary medicinal product is initiated.
Data demonstrate that treatment with Suprelorin will reduce the libido of the dog, but other behavioural changes (e.g. male-associated aggression) have not been investigated.
Special precautions to be taken by the person administering the veterinary medicinal product to animals
Pregnant women should not administer Suprelorin. Another GnRH analogue has been shown to be foetotoxic in laboratory animals. Specific studies to evaluate the effect of deslorelin when administered during pregnancy have not been conducted. Although skin contact with the veterinary medicinal product is unlikely, should this occur, wash the exposed area immediately, as GnRH analogues may be absorbed through the skin. When administering the veterinary medicinal product, take care to avoid accidental self-injection by ensuring that animals are suitably restrained and the application needle is shielded until the moment of implantation. In case of accidental self-injection, seek medical advice immediately and show the package leaflet or the label to the physician, with a view to having the implant removed.
Adverse reactions(frequency and seriousness)
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 the inguinal ring.
Use during pregnancy, lactation or lay
Not applicable
Interactions
None known
Amounts to be administered and administration route
Subcutaneous use.
The recommended dose is one implant per dog, irrespective of the size of the dog.
Disinfection of the implantation site should be undertaken prior to implantation to avoid introduction of infection. If the hair is long, a small area should be clipped, if required.
Remove Luer Lock cap from the implanter. Attach the actuator to the implanter using the Luer Lock connection.
The veterinary medicinal product should be implanted subcutaneously in the loose skin on the back between the lower neck and the lumbar area. Avoid injection of the implant into fat, as release of the active substance might be impaired in areas of low vascularisation. Lift the loose skin between the shoulder blades. Insert the entire length of the needle subcutaneously. Fully depress the actuator plunger and, at the same time, slowly withdraw the needle. Press the skin at the insertion site as the needle is withdrawn, and maintain pressure for 30 seconds. Examine the syringe and needle to ascertain that the implant has not remained within the syringe or needle, and that the spacer is visible.
It may be possible to palpate the implant in situ.
Repeat administration every 12 months to maintain efficacy.
Do not use the veterinary medicinal product if the foil pouch is broken.
The biocompatible implant does not require removal. However, should it be necessary to end treatment, implants may be surgically removed by a veterinarian. Implants may be located using ultrasound.
Overdose
No adverse reactions other than those described in section 4.6 have been observed following simultaneous subcutaneous administration of the equivalent of six implants.
Withdrawal periods
Not applicable
Pharmacological particulars
Pharmacodynamic properties
The GnRH agonist, deslorelin, acts by suppressing the function of the pituitary-gonadal axis when applied in a low, continuous dose. This suppression results in the failure of treated animals to synthesise and/or release follicle stimulating hormone (FSH) and luteinising hormone (LH), the hormones responsible for the maintenance of fertility.
The continuous low dose of deslorelin will reduce the functionality of the male reproductive organs, libido and spermatogenesis and lower the plasma testosterone levels, from 4 to 6 weeks after 10 implantation. A short transient increase in plasma testosterone may be seen immediately after implantation. Measurement of plasma concentrations of testosterone has demonstrated the persistent pharmacological effect of the continuing presence of deslorelin in the circulation for at least 12 months following administration of the veterinary medicinal product.
Pharmacokinetic properties
It has been shown that plasma deslorelin levels peak 7 to 35 days following administration of an implant containing 5 mg radiolabelled deslorelin. The substance can be directly measured in the plasma up to approximately 2.5 months post implantation. The metabolism of deslorelin is rapid.
