メテルゴリン
**メテルゴリン (Metergoline)** は、主に犬の**偽妊娠**の管理に獣医療で使用される**麦角誘導体**の薬剤です。 主な臨床的ポイント： - **プロラクチン阻害薬**として作用し、偽妊娠に伴う不要な乳汁分泌や行動の変化を止めます。 - 妊娠最後の3週間に高用量で投与することで、堕胎薬としての使用が研究されています。 - 米国では市販されていませんが、ヨーロッパや南米で広く使用されています。 - 人医療では、高プロラクチン血症や片頭痛の予防に使用されます。
作用機序: Metergoline reduces prolactin secretion primarily through its **serotonin receptor antagonism**. Mechanistic pathway: - **Serotonin (5-HT) antagonism** → Inhibition of prolactin release from the anterior pituitary. - Unlike other prolactin inhibitors (e.g., cabergoline, bromocriptine), it possesses strong central and peripheral anti-serotonin effects. - Exhibits weak direct **dopamine-2 (D2) agonist** effects and acts as an antagonist at **dopamine-1 (D1) receptors**.
動物種別の用量
- Treatment of pseudopregnancy or to halt post-partum lactation · 0.125 mg/kg PO twice a day · PO · q12h · 4-8 days
- Treatment of pseudopregnancy · 0.5 mg/kg (500 micrograms/kg) PO twice a day · PO · q12h · 4-5 days · Occasional failures can be dealt with by repeating the treatment protocol and extending it to 8 to 10 days, or by using joint protocols of cabergoline plus metergoline or cabergoline plus bromocriptine.
- Treatment of pseudopregnancy · 0.1 mg/kg, PO twice a day · PO · q12h · 8 to 10 days
- Treatment of pseudopregnancy · 0.1 mg/kg q12h PO with food · PO · q12h · 10 days · Side effects were limited to hyperexcitation and nausea, did not lead to termination of therapy, and gradually dissipated during the second week.
- To induce estrus · 0.1 mg/kg PO twice a day · PO · q12h · From 100 days after ovulation until the following proestrus · Results have been variable depending on dosage. Can significantly shorten the interoestrous interval.
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
禁忌
- Pregnancy (unless abortion is desired)
- Nursing mothers
- Hypersensitivity to ergot derivatives
有害事象
- Anxiety
- Aggressiveness
- Depression
- Hyperexcitation
- Whining
- Escaping behavior
- Anorexia
- Vomiting
- Nausea
薬物相互作用
- Bromocriptine · May cause additive effects if used with metergoline
- Cabergoline · May cause additive effects if used with metergoline
- Cyproheptadine · May cause additive effects if used with metergoline
- Metoclopramide · Use with metergoline may reduce the efficacy of both drugs and should be avoided
- SSRIs (e.g., fluoxetine, paroxetine, sertraline) · Potentially could reduce the efficacy of each drug
モニタリング
- Clinical efficacy (resolution of pseudopregnancy signs)
- Adverse behavioral or GI effects
- Liver function tests (if used long-term)
過量投与
Little information is available regarding acute toxicity. **Vomiting** is the most likely clinical sign expected in an overdose situation. Treatment should be supportive and symptomatic.
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。