Diethylstilbestrol
Also known as: Apstil, Boestrol, Destilbenol, Distilbene
Diethylstilbestrol (DES) is a hormone used primarily to treat urinary incontinence (leaking urine) in spayed female dogs. * **Strict Dosing:** It is critical to give this medication *exactly* as prescribed. Giving more than the recommended dose can lead to fatal bone marrow disease. * **Watch for Bleeding/Infection:** Contact your veterinarian immediately if you notice pale gums, unexplained bruising, lethargy, weakness, or fever. * **Watch for Pyometra Signs:** If your pet is an unspayed female, watch for excessive water consumption, frequent urination, or abnormal discharge from the vulva, which could indicate a severe uterine infection. * **Other Signs to Report:** Diarrhea, vomiting, or signs of being in "heat" (swollen vulva, bleeding). * **Handling:** Wash your hands after handling the medication, and keep it strictly out of reach of children and other pets.
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
- Estrogen-responsive incontinence (females)
- Primary sphincter mechanism incompetence (Option A)
- Primary sphincter mechanism incompetence (Option B - females)
- Primary sphincter mechanism incompetence (Option C)
- Estrus induction
- Benign prostatic hypertrophy
How it is given
Possible side effects
- Bone marrow suppression (thrombocytopenia, leukopenia, fatal aplastic anemia)
- Cystic endometrial hyperplasia
- Pyometra (in intact females)
- Mammary neoplasia
- Feminization (in males)
- Signs of estrus (in females)
- Pancreatic, hepatic, and cardiac lesions (reported in cats)
- Malignant ovarian adenocarcinomas (experimental)
Cautions & contraindications
- Food-producing animals (FDA prohibited)
- Pregnancy (teratogenic; causes fetal genitourinary malformations)
- Patients with preexisting anemias or leukopenias
- Females with estrogen-sensitive neoplasms
- **WARNING:** DES is strictly prohibited by the FDA for use in food animals due to carcinogenic potential. * **Bone Marrow Toxicity:** Estrogens are toxic to the bone marrow in dogs and cats. Use with extreme caution in patients with preexisting hematologic abnormalities. Toxicity is dose-dependent and more common in older animals. * **Pyometra Risk:** Can induce cystic endometrial hyperplasia and open-cervix pyometra in intact females 1-6 weeks after initiating therapy. * **Carcinogenicity:** May induce mammary neoplasias and has been linked to malignant ovarian adenocarcinomas in experimental settings.
Drug interactions
- Azole Antifungals (itraconazole, ketoconazole, etc.): May increase estrogen levels
- Cimetidine: May decrease metabolism of estrogens
- Corticosteroids: Enhanced glucocorticoid effects may result; estrogens may alter protein binding or decrease metabolism of corticosteroids
- Erythromycin, Clarithromycin: May decrease the metabolism of estrogens
- Warfarin: Oral anticoagulant activity may be decreased; increases in anticoagulant dosage may be necessary
- Phenobarbital: May decrease estrogen concentrations
- Phenytoin: May decrease estrogen concentrations
- Rifampin: May induce hepatic microsomal enzymes and decrease estrogen levels
Frequently asked questions
What is Diethylstilbestrol used for in pets?
Diethylstilbestrol (DES) is a hormone used primarily to treat urinary incontinence (leaking urine) in spayed female dogs. * **Strict Dosing:** It is critical to give this medication *exactly* as prescribed. Giving more than the recommended dose can lead to fatal bone marrow disease. * **Watch for Bleeding/Infection:** Contact your veterinarian immediately if you notice pale gums, unexplained bruising, lethargy, weakness, or fever. * **Watch for Pyometra Signs:** If your pet is an unspayed female, watch for excessive water consumption, frequent urination, or abnormal discharge from the vulva, which could indicate a severe uterine infection. * **Other Signs to Report:** Diarrhea, vomiting, or signs of being in "heat" (swollen vulva, bleeding). * **Handling:** Wash your hands after handling the medication, and keep it strictly out of reach of children and other pets.
Is Diethylstilbestrol 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.
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