To block (discontinue) and postpone the estrus in dogs and cats; to calm down sexually excited male dogs and cats and changes in the behavior related with this (satyriasis); in case of miliary eczema in cats.
Megestrol is a semi-synthetic derivate of progesterone with progesterone-like action (progestagen). If suppresses the secretion of gonadotropin-releasing hormones from the hypothalamus, respectively of gonadotropic hormones (follicle-stimulating and luteinizing) from the anterior pituitary gland, the maturation of the follicles and the ovulation. A condition similar to pregnancy is achieved, without occurrence of estrus. It is active also for internal administration. The product has anti-estrogen, anti-ovulation and anti-fertility effects.
Do not use in dogs and cats that have not reached sexual maturity; do not use in pregnant dogs and cats and in case of pseudo-pregnancy; in dogs and cats with gynecological disorders on hormonal base and in case of gynecological infections.
Adverse side effects:
If used for a long time (non-adherence to the regimen of administration) in high doses (overdosing), apathy and obesity of the treated dogs and cats, glandule-cystic hyperplasia of the endometrium, fibrous cystic degeneration and tumors of the mammary gland, metritis, pyometra, provocation or exacerbation of diabetes mellitus are possible. In young animals that have not reached sexual maturity, lack of estrus and infertility occur frequently. After discontinuation of the treatment in the recommended doses, irregularity of the sexual cycle is observed.
Drug-drug and other types of interactions:
Only for veterinary medicinal use.
Dosage for each animal species, method and manner of administration
It is administered orally in the following doses depending on the animal species:
Dogs: to discontinue the estrus – 1 - 2 mg/kg body mass (in average 1.5 mg/kg body mass) for 3 days, starting at the moment of the first signs of heat (swelling of the vulva, occurrence of bloody floccules in the estral secretion) and 0.5 - 1 mg/kg body mass in the next 7 days (1 - 2 tablets per day in the first 3 days and 1/2 - 1 tablet per day in the next 7 days); to delay (temporarily postpone) the estrus (in case of transportation, participation in exhibitions and contests, etc.) – 0.5 mg/kg body mass per day, the treatment starting 7 days before the expected heat and lasting for as long as the delay of the estrus is needed (at least 14 days), and if extension of the effect is needed, after 10 days the procedure can be repeated. This can be made only once in 6 months; in case of sexually excited male dogs (satyriasis) with or without aggressiveness or other changes in the behavior, the same doses are used like for discontinuation of the estrus in female dogs.
Cats: to discontinue the estrus – 5 mg/cat (1/2 tablet) per day for 8 consecutive days, starting at the moment of the first signs of estrus; to postpone the estrus – 2.5 mg/cat (1/4 tablet) 3 times a week during the whole estral period; in case of satyriasis in male cats - 2 mg/kg body mass per day for 30 days (until the disappearance of the signs).
No withdrawal period.