1. Drug name:

Diethylstilbesterol

2. Common Names or Brand Names:

Apstil®, Boestrol®, Destibenol®, Distibene®, Honvol®, Stilbestrol®, also known as DES

3. How Dispensed:

Prescription-only - not commercially available in the United States, but can be found through veterinary compounding pharmacies.

4. Forms:

Tablet, liquid, chewable tablet

Liquid forms should be measured carefully.

Because of the potential toxic side-effects of estrogen use, it is always important to use the lowest effective dose for the shortest period of time.

5. Drug Type/Class:

A hormonal agent and a synthetic estrogen.

6. Uses in Dogs and Cats:

Used to treat urinary incontinence in dogs and other diseases responsive to estrogen, including some cancers. The urinary treatment is “extra-label” or “off label” which is acceptable in veterinary medicine.

7. How it works:

Estrogens increase urethral tone and help to prevent leaking or dribbling of urine.

8. Side Effects and/or Signs of Overdose:

The most-serious side-effect of estrogen therapy is bone-marrow suppression and toxicity that may progress to fatal aplastic anemia. (when blood cells are no longer being produced)

Although this serious adverse effect is more common after large or repeated doses, it may occur at the recommended dose. Other side-effects include:

• signs of estrus
• lethargy
• diarrhea
• vomiting
• vaginal discharge
• pyometra (Uterine infection)
• polydipsia (Increased thirst/drinking)
• polyuria (Increased amount/frequency of urination)
• feminization of male dogs

9. Drug Interactions:

Use with caution when giving with:

azole antifungals, bupropion, cimetidine, corticosteroids, erythromycin, clarithromycin, phenobarbital, phenytoin, rifampin, tricyclic antidepressants, or warfarin

Be sure to tell your vet about any medications (including vitamins, supplements, or herbal therapies) that your pet is taking.

10. Cautionary Statements:

• Pregnant women should NOT handle this medication; if it is necessary, wear gloves and wash hands immediately after administering. It can and will penetrate your skin.
• Side effects are more common in older animals.
• DES and other estrogens should not be used during pregnancy as it has been shown to cause fetal malformations
• In cats, serious side effects can result in pancreatic, liver, and heart damage which can cause vomiting, diarrhea, lack of appetite, breathing difficulty, or severe tiredness.
• Complete blood cell counts including platelet counts and liver function tests should be performed prior to starting the medication and routinely, as recommended by your vet if using it long-term.
• Your vet may monitor your pet to be sure that the medication is working.
• Monitor your pet at home for effectiveness and serious side effects.

Read more:

Pet Medication 101: Proin

Why does my pet need a urinalysis?

Urinary Tract Infection (UTI) in Dogs

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