エストリオール
ホルモン - エストロゲン
エストリオールは、下部尿路生殖器のエストロゲン受容体に高い親和性を持つ合成の短時間作用型エストロゲンです。主に避妊手術済みの雌犬における尿道括約筋機能不全（USMI）の管理に使用されます。
作用機序: Estriol binds to **estrogen receptors** in the lower urogenital tract → increases resting urethral muscle tone and mucosal vascularity → improves urodynamic function and urethral closure pressure.
動物種別の用量
Cats
- All indications · Do not use. · PO · N/A · N/A · Contraindicated or not recommended for use in cats.
Dogs
- Urethral sphincter mechanism incompetence (USMI) in spayed bitches · Starting dose: 1 mg/dog. If successful, reduce to 0.5 mg/dog. If unsuccessful, increase to 2 mg/dog. Minimum effective dose: 0.5 mg/dog. Maximum dose: 2 mg/dog. · PO · q24h (can consider q48h for maintenance once response is seen) · Long-term · Alternate-day dosing can be considered once a response has been seen.
用量は獣医療従事者向けの臨床リファレンスです。必ず最新の添付文書と個々の患者で確認してください。
投与経路
PO
禁忌
- Intact bitches
- Polyuria/polydipsia (PU/PD) of unknown origin
- Animals < 1 year old
有害事象
- Oestrogenic effects (swollen vulva, attractiveness to males) in 5-9% of dogs at 2 mg/day
- Bone marrow suppression (rare, but possible with long-term use)
- Gastrointestinal upset (mild)
薬物相互作用
- Phenylpropanolamine · Concurrent administration may potentiate efficacy in treating urinary incontinence (synergistic effect). · minor
モニタリング
- Clinical response (resolution of urinary incontinence)
- Complete Blood Count (CBC) periodically for long-term use to monitor for bone marrow suppression
- Signs of estrogenic side effects (vulvar swelling)
過量投与
Overdose may lead to exaggerated estrogenic effects, including pronounced vulvar swelling, attractiveness to male dogs, and potentially an increased risk of **bone marrow suppression** (anemia, thrombocytopenia, leukopenia). Treatment is supportive and symptomatic; discontinue the drug until signs resolve.
VetSheet の薬剤リファレンスは、獣医療従事者向けの臨床意思決定支援を目的としており、専門的判断やメーカーの最新添付文書に代わるものではありません。