What You Need To Know

Diethylstilbestrol (DES) is a synthetic estrogen. Estrogen is one of the primary ovarian hormones and the pharmacologic actions of DES mimic those of estrogen. In animals, DES is primarily used to treat urinary incontinence in spayed females. Estrogens increase urethral tone and help to prevent leaking or dribbling of urine. DES is often effective for this purpose and the risk of side effects is relatively low due to the relatively small dosages used.

Side Effects: The most serious side effect of estrogen therapy is bone marrow suppression and toxicity that may progress to a fatal aplastic anemia. Estrogen toxicity manifests itself first by leukocytosis, followed by bone marrow depression with anemia, thrombocytopenia, and leukopenia. Blood dyscrasias and changes in the peripheral blood smear may be evident by 2 weeks. Although this serious adverse effect is more common after large or repeated doses, it may occur at the recommended dose. Side effects are more common in older animals. 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. Other side effects include signs of estrus, lethargy, diarrhea, vomiting, vaginal discharge, pyometra, polydypsia, polyuria, and feminization of male dogs.

Precautions: DES and other estrogens should not be used during pregnancy as it has been shown to cause fetal malformations. Daily administration of DES in cats resulted in lesions in the pancreas, liver and heart. Some estrogens have been shown to be carcinogenic in laboratory animals.

Drug Interactions: Rifampin, phenobarbital, and phenylbutazone may decrease the activity of DES due to microsomal enzyme induction. DES and other estrogens may enhance corticosteroid activity. The corticosteroid dose may need to be adjusted. DES and other estrogens may decrease the activity of anticoagulants.

Overdose: Overdosage in humans results in nausea, vomiting and bleeding, similar experiences could be extrapolated to animals.

Owner Information: Keep out of reach of children. Always wash your hands after handling DES.  If you miss a dose, do not give two doses at once.  Store capsules at room temperature, in the original child-resistant container.  If capsules are opened, do not breathe the capsule contents/powder dust.  Never administer DES to animals for which it was not originally prescribed.


DES 1mg #30 = $38.70

Click here to download a pre-printed prescription order form to take to your veterinarian.