Ovaban
Pharmacology - Megestrol acetate pogestationals discusses (e.g., and glucocorticoid activity (with resultant adrenal suppression). It does not have anabolic nor masculinizing effects on the developing fetus.
Uses/Indications - Megestrol acetate (Ovaban - Schering) is approved by FDA for use in dogs only for the postponement of used clinically in the United States and elsewhere for many dermatologic and behavior - related conditions, primarily in the cat. See the dosage section for specific indications and dosages for both dogs and cats.
Megestrol acetate is indicated in humans for the paliative treatment of advance carcinoma of the breast or endometrium.
Contraindications/Precautions - Megestrol acetate is contraindicated in pregnant animals or in animals with uterine disease, diabetes mellitus or mammary neoplasias. It has been recommended that MA not be used in dogs prior to their first estrous cycle or for anestrus therapy in dogs with abnormal cycles. The manufacturer (Schering) recommends that should estrus occur within 30 days of cessation of MA therapy, mating be prevented. For estrus control, the manufacturer ecommends that drug must be given for the full treatment regimen to be effective and that MA should not be given for more than two consecutive treatments.
In humans, megestrol acetate is to be used with caution in patients with thrombophlebitis and is contraindicated as a test for pregnancy.
Doses -
Cats:
For suppression of estrus:
a) 0.5 mg/kg PO once daily for 8 days (Barton and Wolf 1988)
To prevent vaginal hyperplasia developments:
a) 2.2 mg/kg PO fr 7 days (Wykes 1986)
For treatment of severe galactorrhea:
a) .55 mg/kg PO once daily for 7 days 1986)
For adjunctive treatment of aggressive or unacceptable masculine behavior:
b) 1.1 - 2.2 mg/kg PO once daily for 2 wees, then 0.5 - 1.1 mg/kg once daily for 2 weeks. Shoud be used with behavior modification. (Voith and Marder 1988)
Note: I have used Ovaban for stopping a heat cycle, but it has to be monitored carefully, there are many medical problems involved and can cause death or sterilization. The female can stay out of heat from 1/2 year to 1 year.
Fertagyl Therapy (Pro's and Con's)
There are several advantages to this drug. It is a fertility drug, that simulates the ovaries that sheds eggs in large numbers. This can be used for queens that have difficulties in conception. One caution is to be sure the queen has been check by a vet to varify the queen has no infection that are causing her to not have kittens.
Birth Control:
When a queen goes in heat and you want to stop heat cycles, Fertagyl is used to make the queen ovulate, the reasoning behind this is when the queen has mated with a male she ovulates, which then causes her body to think it has been bred and stops heat cycles for at least 2months. One caution though, DON'T let her get bred, if she should become bred, than you can have a large litter of kitten that may be to much for the queen to care for.
This information comes from my many years of working with a certified Vet.
GONADORELIN, CYSTORELIN, FERTAGYL
"Pharmacology"
Gonadorelin stimulates the production and the release of FSH and LH from the anterior pituitary. Secretion of endogenous GnRH from the hypothalamus is thought to be controlled by several factors, including circulating sex hormones.
Gonadorelin causes a surge-like release of FSH and LH after a single injection. In cows and ewes, this can induce ovulation, but not in estrus mares. A constant infusion of gonadorelin will initially stimulate LH and FSH release, but after a period of time, levels will return to baseline.
...
Susan Little DVM, Dipl ABVP (Feline)
Bytown Cat Hospital, Ottawa, Canada
Fertagyl is one brand name for gonadorelin (also called
gonadotrophin-releasing hormone, GnRH). Other brand names include
Cystorelin and Factrel. This drug is not approved for use in cats.
In feline reproduction, its main use has been to stimulate ovulation in
artificial breeding programs for wild felids. It has also been used to
treat infertility in cases where the queen has failed to ovulate. Overall,
inability to ovulate is an uncommon cause for fertility in the queen. The
most common causes lie in breeding management - i.e. breeding too few
times, inexperienced male, etc.
Gonadorelin will induce ovulation only if the cat is already in heat,
either a natural heat or an artificially-induced one. There are dangers
associated with the use of all these reproductive hormones since the
ovaries of the cat are very sensitive to them. It has been demonstrated
that queens may also suffer an immune-mediated decrease in fertility
associated with the frequent use of these drugs.
So using gonadorelin in the situation described above would induce
ovulation and then a false pregnancy (provided the queen is not bred).
their ways are more commonly employed to do the same thing. Sham breedings
can be done with a Q-tip or thermometer, with acupressure, or with a
vasectomized male. All these methods induce a false pregnancy, during which
time the queen's progesterone level is high. A risk associated with this is
the development of pyometra, especially if this is frequently used as a
means of reproductive control in a susceptible queen.
Susan Little DVM, Dipl ABVP (Feline)
Bytown Cat Hospital, Ottawa, Canada
This page was last updated on: May 12, 2002
