Estradiol Cypionate
Also known as: Delestrogen, DepoEstradiol, Depogen, Dura-Estrin, ECP, E-Cypionate, Estra-D, Estrace, Estro-Cyp, Estroject, depGynogen, Femtrace, Gynodiol
- **Severe Risk Warning:** This medication can cause severe, sometimes fatal, damage to the bone marrow in dogs and cats. It is rarely used today for this reason. - Contact your veterinarian **immediately** if your pet shows signs of anemia or bleeding, such as **pale gums, unusual bruising, pinpoint red spots on the skin, or extreme lethargy**. - Watch closely for signs of a severe uterine infection (**pyometra**), which include drinking excessive amounts of water, frequent urination, lethargy, or vaginal discharge. This can occur 1 to 6 weeks after treatment. - **Do not use in pregnant animals**, as it causes severe birth defects. - **Illegal in food animals:** This drug must never be used in animals intended for human consumption.
Dosage must be set by your veterinarian for your specific pet. Never give human medication or another pet’s prescription without veterinary guidance.
What it is used for
- Pregnancy avoidance after mismating
- Any
- To enhance estrus behavior and receptivity in ovariectomized mares
- Treatment of mares with estrogen-responsive incontinence
- Pregnancy avoidance after mismating
How it is given
Possible side effects
- Bone marrow toxicity (thrombocytopenia, leukopenia, fatal aplastic anemia)
- Cystic endometrial hyperplasia
- Pyometra
- Mammary neoplasia
- Feminization (in males)
- Prolonged estrus (in females)
- Genital irritation (cattle)
- Decreased milk flow (cattle)
- Follicular cysts (cattle)
Cautions & contraindications
- Pregnancy (teratogenic and causes fetal bone marrow depression)
- Food-producing animals (illegal per FDA)
- Ferrets (highly susceptible to severe bone marrow toxicity)
- Estrogen-responsive incontinence in small animals (safer alternatives like DES or estriol should be used)
- Use with extreme caution in small animals due to the high risk of **blood dyscrasias** (bone marrow depression), which are more prevalent in older animals and at higher dosages. Toxicity can progress to fatal aplastic anemia. In cows with a prolonged corpus luteum, rule out endometritis or pregnancy before use. **Do not use in ferrets** due to extreme sensitivity to estrogen-induced bone marrow toxicity.
Drug interactions
- Azole Antifungals (fluconazole, itraconazole, ketoconazole): May increase estrogen levels due to CYP450 enzyme inhibition.
- Corticosteroids: Enhanced glucocorticoid effects; estrogens may alter protein binding or decrease metabolism of corticosteroids.
- Macrolide Antibiotics (erythromycin, clarithromycin): May increase estrogen levels.
- Phenobarbital: May decrease estrogen activity via hepatic enzyme induction.
- Rifampin: May decrease estrogen activity via hepatic enzyme induction.
- St. John's Wort: May decrease estrogen activity.
- Warfarin: Oral anticoagulant activity may be decreased; dosage adjustments may be necessary.
Frequently asked questions
What is Estradiol Cypionate used for in pets?
- **Severe Risk Warning:** This medication can cause severe, sometimes fatal, damage to the bone marrow in dogs and cats. It is rarely used today for this reason. - Contact your veterinarian **immediately** if your pet shows signs of anemia or bleeding, such as **pale gums, unusual bruising, pinpoint red spots on the skin, or extreme lethargy**. - Watch closely for signs of a severe uterine infection (**pyometra**), which include drinking excessive amounts of water, frequent urination, lethargy, or vaginal discharge. This can occur 1 to 6 weeks after treatment. - **Do not use in pregnant animals**, as it causes severe birth defects. - **Illegal in food animals:** This drug must never be used in animals intended for human consumption.
Is Estradiol Cypionate safe for my pet?
Dosage must be set by your veterinarian for your specific pet. Never give human medication or another pet’s prescription without veterinary guidance.
This article is for general education and is not a substitute for professional veterinary advice. If your pet is unwell, please consult a veterinarian.
Worried about your pet?
Peqaboo’s AI helps you track symptoms, understand lab reports, and know when to see a vet.
Get the Peqaboo app