Estriol

Indications

INCURIN ® Tablets are indicated for the control of estrogen-responsive urinary incontinence in ovariohysterectomized female dogs.

Dosage and Administration

The dose of INCURIN ® Tablets is not dependent upon body weight. All dogs should receive an initial dose of 2 mg INCURIN ® Tablets (2 tablets) orally once per day for a minimum of 14 days. After urinary incontinence is controlled, the lowest effective daily dose of INCURIN ® Tablets should be determined by decreasing the dose in a step-wise manner from 2 mg once daily (2 tablets) to 1 mg once daily (1 tablet), then 0.5 mg once daily (1/2 tablet) depending upon the response of the individual dog. There should be a minimum of 7 days between each dose adjustment. After the lowest daily dose that controls urinary incontinence is identified, the dose may be decreased further by administering once every two days. Dogs should not receive more than 2 mg INCURIN ® Tablets per day (2 tablets). If the dog does not respond to 2 mg of INCURIN ® Tablets per day, the diagnosis should be re-assessed.

Warnings

Human Warnings: Not for human use. Keep out of the reach of children. Women who are of child-bearing age or those who are breastfeeding should use caution when administering INCURIN ® Tablets. Wash your hands with soap and water after administration to avoid exposure to the drug. Consult a physician in case of accidental ingestion by humans. Animal Warnings: Some estrogens have been associated with bone marrow changes and an increased risk of mammary tumors. However, target animal safety study results and foreign post-market pharmacovigilance data for INCURIN ® Tablets have shown that estriol-treated dogs are at low risk for developing these conditions.

Precautions

Evaluation of factors contributing to urinary incontinence should be considered prior of administration of INCURIN ® Tablets. Do not use with other estrogens. The concomitant use of INCURIN ® Tablets with other estrogens has not been evaluated. The concomitant use of INCURIN ® Tablets with glucocorticoids has not been evaluated. The use of INCURIN ® Tablets in dogs with liver disease has not been evaluated. The safe use of INCURIN ® Tablets has not been evaluated in intact female dogs, pregnant or lactating dogs, male dogs, and dogs less than 1 year of age.

Adverse Reactions

In the initial phase of a placebo-controlled field study conducted to determine effectiveness, 115 of 226 dogs were dosed with INCURIN ® Tablets orally at 2 mg per day for 14 days. Adverse reactions during the first study phase included primarily gastrointestinal and estrogenic effects, as summarized in Table 1. Table 1: Reported adverse reactions during 14 days of treatment with either INCURIN ® Tablets dosed at 2 mg per day or placebo Adverse Reaction INCURIN ® Tablet Group % of dogs (n = 115) Placebo Group % of dogs (n = 111) Anorexia 13.0% 3.6% Emesis 9.6% 6.3% Polydipsia 7.0% 7.2% Swollen vulva 4.3% 0.0% Anxiety 3.5% 2.7% Sexual attractiveness 3.5% 1.8% Somnolence 1.7% 0.0% Hypersalivation 1.7% 0.0% Estrous behavior 0.9% 0.0% Mammary hyperplasia 0.9% 0.0% In the second phase of the field study, all dogs received treatment with INCURIN ® Tablets from Day 14 to Day 42; the drug dose was adjusted up or down (not to exceed 2 mg per day) at weekly intervals depending on whether urinary incontinence was controlled. Table 2 summarizes reported adverse reactions in dogs treated with INCURIN ® Tablets during the second study phase. Adverse reactions tended to lessen when dogs received lower drug doses. One dog that received 10 doses of estriol was removed due to suspected uterine stump pyometra. The relationship between this adverse reaction and INCURIN ® Tablets could not be determined. Table 2: Reported adverse reactions during the second study phase (days 14-42) Adverse Reaction INCURIN ® Tablets Group % of dogs (n = 224) Anorexia 12.9% Emesis 7.6% Licking vulva 4.5% Swollen vulva 4.0% Vulvovaginitis 4.0% Lethargy 4.0% Polydipsia 3.6% Aggression 1.8% Hyperactivity 1.8% Cystitis 1.3% Anxiety 0.9% Mammary hyperplasia 0.9% Somnolence 0.9% Estrous behavior 0.9% Sexual attractiveness 0.4% Alopecia (local) 0.4% Extended-use studies continued after the field studies involving more than 300 dogs. Additional adverse reactions to those seen in the field studies included hyperpigmentation and lichenification of the vulva. Also, 3 dogs receiving INCURIN ® Tablets were euthanized due to aggressive behavior. Foreign market experience: Foreign post-market pharmacovigilance data for INCURIN ® Tablets were collected from the years 2000 through 2010 by Intervet, Inc. Approximately 20% of reported adverse events were for local or general alopecia. Vaginal hemorrhage, possible stump pyometra, an increase in epileptic seizures, and anemia, leukopenia, and thrombocytopenia were seen in 1 or more dogs. Other adverse events reported were similar to those seen during the US studies. For technical assistance or to report suspected adverse reactions call Intervet at 1-800-224-5318. For a copy of the Material Safety Data Sheet (MSDS), call 1-800-770-8878.

Description

INCURIN ® (estriol) Tablets contain 1 mg of estriol per tablet. USP Chemical Name: Estra-1,3,5(10)-triene-3,16,17-triol, (16 α ,17 β )-. USP Molecular Weight: 288.38 USP Solubility: Soluble in acetone, in chloroform, in dioxane, in ether, and in vegetable oils; sparingly soluble in alcohol; insoluble in water. Structure

Storage

Store at or below 25°C (77°F) with excursions permitted to 40°C (104°F)

FDA adverse event reports

The FDA Center for Veterinary Medicine publishes the adverse event reports it receives through openFDA. The counts below are the reports naming estriol as an active ingredient for each species this label names, as returned on 2026-09-16, coded by the VeDDRA reaction term the reporter chose. Reactions are counted per report, so one report can appear under several terms.

These are counts, not rates. Reporting is voluntary, the number of animals treated is not known, and a widely used product accumulates reports for that reason alone. A report records that an event followed a dose; it does not establish that the product caused it. The counts say nothing about how one product compares with another.