Suprelorin

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Deslorelin (Suprelorin), manufactured in Australia by Virbac is an anti-androgenic hormone (GnRH agonist) used as an off-label treatment for oestrus and prevention of puberty-onset[1] in male and female cats[2]. It has also been used in cats for conditions such as ovarian remnant syndrome and inappropriate elimination. Deslorelin was initially developed in Australia as an ovulation-inducing agent in mares.

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Deslorelin effects contraception by temporarily suppressing the reproductive endocrine system, preventing production of pituitary (FSH and LH) and gonadal hormones (estradiol and progesterone in females and testosterone in males). Implanted deslorelin appears active in suppressing the function of the pituitary-gonadal axis and thus sexual activity for 8-12 months, although longer periods of anoestrus have been reported[3][4]. Unlike other GnRH agonists, which are mainly used to inhibit luteinizing hormone and follicle-stimulating hormone by their ultimate down-regulation of the pituitary gland, Deslorelin is primarily used for the initial flare effect upon the pituitary, and its associated surge of LH secretion[5].

Uses

Deslorelin is indicated for use in oestrus-suppression in Queens and for chemical sterilisation in Toms. This drug may obviate the need for vasectomy in males, although the risk of unwanted pregnancies exist as the chemical wears off.

It is also warranted as a method for treatment of inappropriate elimination (spraying) in both sexes of cats.

The observed effects are similar to those following ovariectomy or castration, but are reversed after the hormone content of the implant is depleted. As a hormone agonist, deslorelin first stimulates the reproductive system, which can result in estrus and ovulation in females or temporary enhancement of testosterone and semen production in males. Down-regulation of gonadotrophin then follows the initial period of stimulation.

In tomcats treated with deslorelin, libido, mating behaviour and urine marking were significantly reduced after an initial stimulation[6].

Few side-effects have been reported with this drug[7]. Trials to date have focused primarily on domestic dogs, although there has been one controlled study in domestic cats and preliminary data from a number of cheetahs and lions[8].

In cases of delayed return to normal sexual activity, oestrus can be induced in the Queen with subcutaneous injections (every 3 days) of 200 I.U. Folligon (serum gonadotrophin) until oestrus resumes.

Dose

Deslorelin is available as a single 4.7 mg bio-compatible implant for use in cats. A single implant is injected subcutaneously. Although most veterinarians implant the device in the periscapular region (scruff), it is recommended to implant the device in the inguinal area (preferably a glabrous region) should the device need to be removed at a later date.

Repeated implant use may be efficacious in case which respond to therapy but no long-term studies have been reported about multiple use in felines.

The implant is difficult to remove if reversal is desired before the hormone in the implant becomes depleted, since the implant breaks easily. However, careful implant insertion to avoid breakage can facilitate later removal[9].

References

  1. Risso A et al (2012) Long-Term-Release GnRH Agonists Postpone Puberty in Domestic Cats. Reprod Domest Anim Feb 15. doi: 10.1111/j.1439-0531.2012.01994.x.
  2. Malik R et al (2011) Deslorelin implants - a new choice in feline reproductive medicine. J Feline Med Surg 13(11):874-875
  3. Toydemir TSet al (2012) Effects of the GnRH analogue deslorelin implants on reproduction in female domestic cats. Theriogenology 77(3):662-674
  4. Euclid, JM (2010) Pers comm
  5. Wikipedia.org
  6. Goericke-Pesch S et al (2011) Clinical efficacy of a GnRH-agonist implant containing 4.7 mg deslorelin, Suprelorin, regarding suppression of reproductive function in tomcats. Theriogenology 75(5):803-810
  7. Munson L et al (2001) Efficacy of the GnRH analogue deslorelin for suppression of oestrous cycles in cats. J Reprod Fertil Suppl 57:269-273
  8. Bertschinger HJ, et al (2001) Control of reproduction and sex related behaviour in exotic wild carnivores with the GnRH analogue deslorelin: preliminary observations. J Reprod Fertil Suppl 57:275-283
  9. Trigg T.E., et al (2006) A review of advances in the use of the GnRH agonist deslorelin in control of reproduction. Theriogenology 66:1507-1512