シリマリン / マリアアザミ
**シリマリン (Silymarin)** は、マリアアザミ (*Silybum marianum*) の種子から抽出されるフラボノリグナン複合体です。獣医療において**肝保護栄養補助食品**として広く利用されています。 * **主な用途:** 犬、猫、その他の動物における急・慢性肝疾患、肝硬変、炎症性肝疾患の管理。 * **毒物解毒:** タマゴテングタケ (*Amanita phalloides*) などの重篤な肝毒性物質を摂取した後の肝保護剤として特に重要視されています。 * **腫瘍学のサポート:** 最新の実験データでは、特定のガンの予防や、特定の化学療法による肝毒性の副作用を軽減する可能性が示唆されています。 > **臨床のポイント:** シリマリンは栄養補助食品であるため、市販品の品質や生体利用率には大きなばらつきがあります。シリビニンをホスファチジルコリンと結合させた（フィトソーム技術）獣医専用の製剤は、標準的な抽出物と比較して胃腸からの吸収が非常に優れているため、強く推奨されます。
作用機序: Silymarin exerts its hepatoprotective effects through multiple synergistic pathways. **Silibinin** (or silybin) is the most biologically active component of the complex. * **Antioxidant & Free Radical Scavenging:** Inhibits lipid peroxidase and beta-glucuronidase. It directly scavenges reactive oxygen species (ROS) and significantly increases intracellular **glutathione** levels in the liver. * **Membrane Stabilization:** Alters the outer hepatocyte cell membrane structure, competitively blocking the binding and transmembrane transport of hepatotoxins (e.g., amatoxins from poisonous mushrooms). * **Anti-inflammatory:** Inhibits the cytotoxic, inflammatory, and apoptotic effects of **Tumor Necrosis Factor-alpha (TNF-α)** and modulates leukotriene synthesis. * **Antifibrotic:** Reduces hepatic stellate cell activation, thereby decreasing hepatic collagen formation and slowing the progression of cirrhosis. * **Regenerative:** Stimulates ribosomal RNA polymerase A → enhances protein synthesis and accelerates hepatocyte regeneration.
動物種別の用量
- Therapeutic dosage (general) · 50-250 mg/day · PO · q24h · Suggested dose range
- Adjunctive therapy for chronic liver disease · 20-50 mg/kg per day · PO · q24h · Extrapolated from human, monkey, rodent and dog research
- Chronic liver disease and ameliorating the effects of anticonvulsants · 50-200 mg · PO · q12-24h
- Hepatotoxicity, hepatic recovery/regeneration, hepatic fibrosis · 20-50 mg/kg/day · PO · q24h
- General hepatic support · 4-8 mg/kg/day · PO · q24h
- Therapeutic dosage (general) · 50-250 mg/day · PO · q24h · Suggested dose range
- Adjunctive therapy for chronic liver disease · 20-50 mg/kg per day · PO · q24h · Extrapolated from human, monkey, rodent and dog research
- Chronic liver disease and ameliorating the effects of anticonvulsants · 50-200 mg · PO · q12-24h
- Hepatotoxicity, hepatic recovery/regeneration, hepatic fibrosis · 20-50 mg/kg/day · PO · q24h
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
- Known hypersensitivity or allergy to the Asteraceae/Compositae plant family (ragweed, marigolds, daisies)
- Use caution with whole plant extracts (not the seed extract) in patients where exogenous estrogens are contraindicated, due to potential estrogen-like activity
有害事象
- Gastrointestinal upset (mild nausea, vomiting, diarrhea)
- Allergic reactions in patients sensitive to the Asteraceae/Compositae plant family
- Generally very well tolerated
- Rare mild gastrointestinal upset
薬物相互作用
- CYP2C9 Substrates (e.g., warfarin, amitriptyline, verapamil) · Silymarin may inhibit cytochrome P450 isoenzyme 2C9 (CYP2C9). Use caution with narrow therapeutic index drugs metabolized by this pathway.
- CYP3A4 Substrates · May inhibit CYP3A4, though clinical significance is currently undetermined.
- Drugs undergoing hepatic glucuronidation (acetaminophen, diazepam, morphine, lamotrigine) · Silymarin may increase the clearance of these drugs (not applicable in cats). Clinical significance is undetermined.
モニタリング
- Clinical efficacy (resolution of clinical signs)
- Liver enzyme panels (ALT, AST, ALP, GGT)
- Hepatic function tests (Bilirubin, Bile Acids, BUN, Albumin)
- Liver enzymes (ALT, AST, ALP, GGT)
- Total bilirubin
- Bile acids
- Clinical signs of hepatic disease (e.g., icterus, lethargy, appetite)
過量投与
Overdoses are highly unlikely to cause significant morbidity due to the supplement's high safety margin. Mild gastrointestinal effects (vomiting, diarrhea) may be seen and should be treated in a supportive and symptomatic manner.
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。