Low-dose megestrol acetate revisited: A viable adjunct to surgical sterilization in free roaming cats?

Suppression of Fertility in Adult Cats

“…; Munson ; Greenberg et al. ) such as cystic endometrial hyperplasia–pyometra complex (Agudelo ), mammary tumours and fibroadenomatosis (Wehrend et al. ; Loretti et al.…”

“…According to the literature, differences regarding the frequency of side effects exist depending on the active ingredient (with a significantly lower frequency observed after megestrol acetate and proligestone treatment compared to medroxyprogesterone acetate) and depending on the duration of treatment (the longer, the higher the risk) (Romagnoli and Concannon ; Greenberg et al. ). Jackson () recommended not to use medroxyprogesterone acetate in cats; however, in Europe, it is still widely used by cat breeders and owners.…”

“…Treatment is particularly challenging with feral or free‐roaming cats as regular oral treatment, or implants/injections are needed, and non‐target species uptake is to be avoided (Greenberg et al. ).…”

“…They are also considered to lead to a decreased release of GnRH, follicle-stimulating hormone (FSH) and luteinizing hormone (LH) by a negative feedback on the hypothalamus and pituitary gland (Munson 2006). Without sufficient care, they might induce severe side effects (Johnston et al 2001;Munson 2006;Greenberg et al 2013) such as cystic endometrial hyperplasia-pyometra complex (Agudelo 2005), mammary tumours and fibroadenomatosis (Wehrend et al 2001;Loretti et al 2005) and insulin resistance causing diabetes mellitus (Johnston et al 2001;Munson 2006). According to the literature, differences regarding the frequency of side effects exist depending on the active ingredient (with a significantly lower frequency observed after megestrol acetate and proligestone treatment compared to medroxyprogesterone acetate) and depending on the duration of treatment Differences between two studies published (Gimenez et al 2009, Faya et al 2011 Leaflet recommendation refers to national registrations in Germany: Intervet Deutschland GmbH, 85716 Unterschleissheim, Germany; Albrecht GmbH, 88326 Aulendorf, Germany; Selectavet Dr. Otto Fischer GmbH, 83629 Weyarn-Holzolling, Germany.…”

“…(the longer, the higher the risk) (Romagnoli and Concannon 2001;Greenberg et al 2013). Jackson (1984) recommended not to use medroxyprogesterone acetate in cats; however, in Europe, it is still widely used by cat breeders and owners.…”