What is Estradiol?
Estradiol is a prescription estrogen (estradiol cypionate) used to induce estrus (start the heat cycle) in horses. In the past it was used to prevent pregnancy (mis-mate shot) in dogs and cats, and to treat urinary incontinence, but is generally not recommended for those purposes now since other therapies are available.
Who is it for?
Estradiol is for horses, and rarely for dogs and cats due to its toxicity.
What are the benefits?
||Prescription estrogen, estradiol cypionate
||Used to induce estrus in horses
||Available in convenient tablet form
Estradiol is the prescription estrogen, estradiol cypionate.
How does Estradiol work?
Estradiol is an estrogen, which is a hormone that when elevated induces (starts) estrus in horses.
Is there a generic equivalent available?
This is a generic medication.
How is it given?
Estradiol is given by mouth. Always follow the dosage instructions provided by your veterinarian. If you have difficulty giving the medication, contact your veterinarian. This medication should only be given to the horse/pet for whom it was prescribed.
What results can I expect?
Estrus will usually begin two to three days after treatment.
What form(s) does it come in?
Common Drug Name
What should I discuss with my veterinarian while considering Estradiol?
Talk to your veterinarian about what type of outcome is expected. Have your veterinarian explain the other treatment options that may be available.
Tell your veterinarian if your horse could be pregnant.
Notify your veterinarian of any other medications or supplements your horse is taking, or if your horse has had any reactions to previous medications.
What is the most important information I should know?
Estrus in horses will usually begin two to three days after treatment. If used in dogs and cats, toxic reactions can occur and the animal should be very carefully monitored with laboratory testing.
Who should not take it?
Not for use in animals hypersensitive (allergic) to it or drugs similar to it. Do not use in pregnant or lactating animals (female animals nursing their young). It can cause abortions and birth defects. Do not use in animals with cancers that may be caused by estrogens such as mammary (breast) cancer. Do not use in animals with bone marrow suppression. Do not use in males that are to be used for breeding.
Estrodiol can cause significant adverse side effects in cats and dogs and is generally not recommended for use in those species.
What side effects may be seen when taking Estradiol?
Side effects are not common when used in horses. When used in cats and dogs, side effects can be very serious and even life-threatening. May see lack of appetite, vomiting, diarrhea, vaginal discharge, pyometra (infection in the uterus), lethargy, increased thirst and urination, bone marrow suppression, aplastic anemia, bleeding, and death. Use in males may cause feminization.
How is it stored?
Store in a tight, light-resistant, childproof container at room temperature. Avoid freezing. Keep out of reach of children and pets.
What should I do if I know of or suspect there has been an overdose?
If you know or suspect your horse has had an overdose, contact your veterinarian immediately.
What should I avoid when giving my pet Estradiol?
Consult your veterinarian before using ECP with vitamins and supplements, rifampin, phenobarbital, phenylbutazone, corticosteroids, or oral anticoagulants (such as warfarin), since interactions may occur.
Where is more information available?
Ask your veterinarian, consult with one of our pharmacists at 1-800-447-3021, or see the
Patient Information Sheet on this medication.