Diethylstilbestrol for Dogs

Molly Price, DVM
By Molly Price, DVM on Dec. 13, 2023
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PetMD’s medications content was written and reviewed by veterinary professionals to answer your most common questions about how medications function, their side effects, and what species they are prescribed for. This content shouldn’t take the place of advice by your vet.

What Is Diethylstilbestrol for Dogs?

Diethylstilbestrol (DES) is an estrogen hormone medication prescribed by veterinarians to treat urinary incontinence (urine leaking) in female dogs.

Diethylstilbestrol may be used as a sole medication but is often used in combination with Proin® (phenylpropanolamine), which can also help improve urinary incontinence but through a different pathway. These two medications given together may have a higher chance of success than when used alone.

Diethylstilbestrol is no longer an FDA-approved medication for humans. However, a reputable veterinary compounding pharmacy may use diethylstilbestrol to compound a formulation as prescribed by your veterinarian.

In certain circumstances, your vet may recommend a compounded formulation of diethylstilbestrol. Compounded medications are prescribed if there’s a specific reason your pet’s health can’t be managed by an FDA-approved drug, such as if your pet has trouble taking pills in capsule form, the dosage strength is not commercially available, or the pet is allergic to an ingredient in the FDA-approved medication.

Compounded medications are not FDA-approved. They are created by either a veterinarian or a licensed pharmacist on an individual basis to best suit a patient’s particular needs. You can learn more about compounded medications here.

Diethylstilbestrol Considerations for Dogs

Diethylstilbestrol should not be used in dogs with certain medical conditions such as cancer that is sensitive to estrogen, bone marrow depression such as anemia (low numbers of red blood cells) or leukopenia (low numbers of white blood cells), or in dogs who are pregnant, lactating, or are hypersensitive to it. Diethylstilbestrol should be used with caution in dogs with liver disease.

Giving diethylstilbestrol with certain medications can result in health risks to your pet, so it is important to discuss your pet’s medications, including vitamins and supplements, and medical conditions with your veterinarian.

Treatment with diethylstilbestrol requires routine monitoring and supervision by your veterinarian. They will perform lab tests to evaluate your pet’s immune system function and the effects of the medication on the liver and kidneys.

Diethylstilbestrol is not used in cats due to toxic side effects.

How Diethylstilbestrol Works in Dogs

Diethylstilbestrol is an estrogen hormonal medication that works by improving the tone and strength of the sphincter muscle of the urethra, thereby decreasing urine leaking from the bladder.

Diethylstilbestrol Directions for Dogs

Follow the directions on the drug label or as provided by your veterinarian.

Diethylstilbestrol can be given with or without food, but giving it with food can decrease the risk of digestive upset.

Do not give diethylstilbestrol to breeding or pregnant dogs, as birth defects may occur, or to nursing dogs, as the medication is secreted into breast milk.

Diethylstilbestrol should not be used in cats because it can cause serious bone marrow, pancreas, liver, and heart conditions.

Missed a Dose?

Speak with your veterinarian about what to do if you forget to give a dose of diethylstilbestrol. Generally, they may instruct you to give it when you remember, or if it is almost time for your pet’s next dose, to skip the missed dose and resume your normal dosing schedule. Do not give extra or double doses.

Diethylstilbestrol Possible Side Effects in Dogs

When used at the lowest effective dose for urinary incontinence, diethylstilbestrol is typically well-tolerated in animals. Unspayed female dogs may have mild blood spotting from the vagina as a minor side effect.

Serious side effects of diethylstilbestrol are typically associated with higher dosages and may include:

  • Bone marrow toxicity–symptoms include fever, bleeding, bloody diarrhea, bruising, and infection

  • Uterine infection (pyometra)–symptoms include vaginal discharge, vomiting, loss of appetite, increased thirst, increased urination, and low energy (lethargy)

  • Mammary tumors (lumps in and around the nipples)–or ovarian tumors

Human Side Effects

Diethylstilbestrol is not for use in humans in any capacity. If you are pregnant, trying to become pregnant, or breast-feeding, talk to your veterinarian about the possibility of administering an alternative medication to your pet.

Ensure that you do not ingest diethylstilbestrol. Always wear disposable gloves while in contact with this medication and wash your hands with soap and water after handling.

If you accidentally ingest this medication, immediately call your physician or the national Poison Control Center hotline at 800-222-1222.

Call Your Vet If:

  • Severe side effects are seen (see above)

  • Your pet’s condition worsens or does not improve with treatment

  • You see or suspect an overdose

You have additional questions or concerns about the use of diethylstilbestrol

Diethylstilbestrol Overdose Information in Dogs

An overdose of diethylstilbestrol may cause serious symptoms associated with bone marrow toxicity or pyometra such as weakness, fever, bleeding, bloody diarrhea, bruising, vaginal discharge, vomiting, loss of appetite, increased thirst and urination, or low energy (lethargy).

If you suspect an overdose, immediately contact your veterinarian, seek emergency veterinary care, or call an animal poison control center. Consultation fees often apply.

Pet Poison Helpline (855) 764-7661

ASPCA Animal Poison Control (888) 426-4435

Diethylstilbestrol Storage for Dogs

Always confirm storage requirements by reading the prescription label.

Diethylstilbestrol should be stored at controlled temperatures from 68 F to 77 F. Keep the container tightly closed to protect the medication from moisture and light.

Compounded medications should be stored according to the compounding pharmacy’s label.

Keep out of reach of children and pets.

Diethylstilbestrol for Dogs FAQs

What is diethylstilbestrol used for in dogs?

Diethylstilbestrol is prescribed by veterinarians to treat urinary incontinence (urine leaking) in female dogs.

Is diethylstilbestrol safe for dogs?

Diethylstilbestrol can be used safely in female dogs at the lowest effective dose for urinary incontinence, but under very specific circumstances and only under direct supervision by their veterinarian.

Diethylstilbestrol should not be used in dogs with certain medical conditions and can interact with some types of prescription medications. Speak with your vet first to ensure this medication is appropriate for your dog.

What are the side effects of diethylstilbestrol in dogs?

Diethylstilbestrol is generally well tolerated in female dogs. A mild side effect of diethylstilbestrol may include some blood spotting from the vagina in unspayed female dogs. Serious side effects are generally associated with higher dosages and may include bone marrow toxicity, infection of the uterus (pyometra), mammary tumors, or ovarian tumors.

No vet writer or qualified reviewer has received any compensation from the manufacturer of the medication as part of creating this article. All content contained in this article is sourced from public sources or the manufacturer.

Featured Image: eclipse_images/E+ via Getty Images Plus

Molly Price, DVM


Molly Price, DVM


Dr. Molly Price has practiced small animal medicine for over 20 years and is a graduate of Texas A&M College of Veterinary Medicine. She...

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