Chronic Use of Deslorelin in Dogs: Six Cases (2005–2022)

SIMPLE SUMMARY: This paper presents six different cases of dogs treated repeatedly with deslorelin, a drug responsible for a six- or twelve-month block of the reproductive system which is registered for use in adult male dogs and ferrets, male cats and prepuberal bitches. Efficacy and safety as well as return to fertility of such non-surgical neutering methods are well known following a single use but little if any data is available on prolonged use. The dogs presented in this paper were treated for 2 to 9 consecutive years for ensuring failure to reproduce (one case) as well as for conditions which are not found on the drug leaflet (benign prostatic hypertrophy and perineal gland disease (one case each) and control of reproductive behavior in male dogs and urinary incontinence in spayed adult bitches (two cases each). All animals were in good health during treatment and presented no short-term side effects. Flare-up reactions (an increase in reproductive behavior for 1–3 weeks after treatment) were observed in 1/4 intact males and were not observed in the spayed incontinent bitches. Deslorelin was effective in all treated dogs. Fertility was immediately regained in one male dog who sired a litter when his owner forgot to come back for re-treatment at the right time. Deslorelin implants can be considered as a safe alternative to surgical castration in specific pathologies mediated by reproductive hormones in situations in which surgical castration is not an option such as animals suffering from cardiovascular conditions or other systemic diseases making anesthesia unsafe. ABSTRACT: Deslorelin is currently registered for the induction of temporary infertility in male dogs, male cats, male ferrets, and also prepubertal female dogs, but research has shown its usefulness for other conditions requiring chronic treatment. This paper presents six cases of dogs chronically treated with deslorelin for indications such as benign prostatic hyperplasia, control of fertility, abnormal reproductive behavior and urinary incontinence. All animals were in good health during treatment. Treatment duration was 2–9 years. No short-term side effects were observed except for flare-up reactions, which were observed only in 1/4 intact males. Two dogs developed a neoplasia: a spayed bitch treated for urinary incontinence developed a pituitary carcinoma, and an intact male dog implanted for control of fertility developed a bladder carcinoma. While the pituitary carcinoma seems unlikely to be related to deslorelin, the bladder carcinoma could be due to the neutered condition of the dog (which was treated for 9 years) as urinary tract neoplasia is more common in dogs following gonadectomy. Chronic treatment with deslorelin is regarded as safe when an animal is being treated for life. The possibility that a pause in the treatment might be helpful for the animal should be investigated.