Estriol for incontinence in the hypertensive bitch
11-year-old spayed crossbreed bitch with incontinence at rest consistent with urethral sphincter incompetence. She has stage B2 myxomatous mitral valve disease and repeated systolic blood pressure of 175 mmHg.
Which treatment option is most appropriate?
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A. Oral estriol, tapering to the lowest effective dose and monitoring for oestrogenic signs
Correct. Estriol acts on urethral oestrogen receptors and has no alpha-adrenergic effect, so it does not worsen hypertension or cardiac workload. Monitor for vulval swelling, attraction of males and, rarely, haematological changes.
B. Phenylpropanolamine at the usual dose, because it is the most effective drug
It is the most effective, but it is a sympathomimetic that can raise blood pressure and heart rate; in this hypertensive bitch with heart disease it is not the first choice.
C. Colposuspension surgery straight away, without trying medical treatment
Surgery is reserved for cases that do not respond to medical treatment; here there is a safe pharmacological alternative without anaesthesia.
D. Withdraw pimobendan, which is the likely cause of the incontinence
In stage B2 pimobendan is indicated and does not cause urethral incontinence. Withdrawing it would worsen the cardiac prognosis without solving the problem.
lightbulb Key takeaway
Phenylpropanolamine and estriol have different mechanisms and can be combined if one alone is not enough. In dogs with heart disease, hypertension or kidney disease, start with estriol. Do not use oestrogens in entire bitches and always aim for the lowest dose that keeps the bitch dry.
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Updated: October 31, 2026 · Educational content for veterinary professionals. It does not replace current clinical guidelines or the judgement of the attending veterinarian.