ダルテパリン
ダルテパリンナトリウムは、主に血栓塞栓性疾患の予防および治療に使用される**低分子量ヘパリン（LMWH）**です。 * **機序の利点**: 未分町ヘパリン（UFH）と異なり、ダルテパリンなどのLMWHは薬物動態が予測しやすく、トロンビンよりも第Xa因子を優先的に標的とするため、自発出血のリスクを軽減します。 * **獣医療における課題**: ヒトでは1日1回または2回の投与で高い効果を発揮しますが、犬や特に猫はダルテパリンを非常に早く排泄します。そのため頻繁な皮下注射（猫では最大4〜6時間おき）が必要となり、長期的な外来管理が非常に困難かつ高額になります。 * **臨床的有用性**: 免疫介在性溶血性貧血、蛋白漏出性膾疾患、猫の大動脈血栓塞栓症、馬の花痛など、血栓症のリスクが高い患者に対して、救急・集中治療の現場でよく使用されます。
作用機序: Dalteparin exerts its anticoagulant effect by binding to and accelerating **antithrombin III (ATIII)**. * **Conformational Change**: Binding induces a conformational change in ATIII, significantly accelerating its ability to inactivate coagulation factors. * **Factor Xa Selectivity**: Because dalteparin consists of shorter polysaccharide chains (average molecular weight ~5000 daltons) compared to unfractionated heparin, it lacks the chain length required to simultaneously bridge ATIII and thrombin (Factor IIa). Therefore, it preferentially inhibits **Factor Xa**. * **Pathway**: Dalteparin + ATIII → **Potent inhibition of Factor Xa** → Decreased conversion of prothrombin to thrombin → Prevention of fibrin clot formation. *Clinical Pearl*: Because it minimally impacts thrombin, routine clotting times like TT or aPTT are usually unaffected and are poor monitoring tools for this drug.
動物種別の用量
- Thromboembolic disease prophylaxis/treatment · 150 Units/kg · SC · q4h · Required to maintain a therapeutic target of anti-XA activity of 0.5-1 IU/mL.
- Thromboembolic disease prophylaxis/treatment · 180 Units/kg · SC · q4-6h · Current clinical dose recommendation.
- Prophylaxis of coagulation disorders in colic patients · 50 Units/kg · SC · q24h · Once daily dosing.
- Thromboembolic disease prophylaxis/treatment · 150 Units/kg · SC · q8h · Initial dose 150 Units/kg SC q8h.
- Thromboembolic disease prophylaxis/treatment · 150 Units/kg · SC · TID or BID · 150 Units/kg SC three times daily; twice daily dosing may be effective. Studies are ongoing.
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
- Hypersensitivity to dalteparin, heparin, or pork products
- Active major bleeding
- Heparin-induced thrombocytopenia
- Thrombocytopenia associated with positive in vitro tests for anti-platelet antibodies in the presence of dalteparin
- Intramuscular (IM) or Intravenous (IV) administration
有害事象
- Hemorrhage (unlikely but possible)
- Injection site hematomas or pain
- Allergic reactions
- Neurologic sequelae secondary to epidural or spinal hematomas
薬物相互作用
- Warfarin · Increased risk for hemorrhage
- Aspirin · Increased risk for hemorrhage
- Clopidogrel · Increased risk for hemorrhage
- Thrombolytic agents · Increased risk for hemorrhage
モニタリング
- Baseline and ongoing CBC (with platelet count)
- Urinalysis
- Stool occult blood test
- Factor Xa activity (Note: To measure peak anti-Xa activity in cats, sample at 2 hours post-dose)
過量投与
Overdosage may lead to hemorrhagic complications. If treatment is necessary, **protamine sulfate** via slow IV may be administered. * **Dose ratio**: 1 mg of protamine sulfate can inhibit the effects of 100 units of administered anti-Xa dalteparin. * **Caution**: Avoid overdoses of protamine, as it has its own anticoagulant properties and can cause severe hypotension or anaphylactoid reactions.
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。