メシル酸デフェロキサミン
**メシル酸デフェロキサミン**は、獣医療において主に急性鉄中毒（鉄サプリメントや脱酸素剤の誤飲など）の救命解毒剤として利用される、特異性の高い**鉄キレート剤**です。アルミニウム中毒の治療や急性心筋虚血の補助療法として評価されることもありますが、再灌流障害に対する有効性は期待外れに終わっています。 主な臨床的ポイント： * **高親和性**：血流や組織内の遊離鉄を特異的に標的として結合し、鉄誘発性の酸化損傷を防ぎます。 * **尿の変色**：キレート化が成功した証拠として、サーモンピンクまたは「ロゼワイン」色の尿が生成されます。これは鉄キレート複合体が排泄されていることを示します。 * **投与方法**：非経口（通常はIMまたはゆっくりとしたIV持続点滴）で投与する必要があります。経口投与は、胃腸からの鉄吸収を逆説的に増加させる可能性があるため、一般的に禁忌とされています。
作用機序: Deferoxamine acts by directly binding to free iron to neutralize its toxicity: * The drug possesses three hydroxamic groups that have a high affinity for **ferric (Fe³⁺) ions**. * Deferoxamine + Fe³⁺ → **Ferrioxamine** (a stable, water-soluble chelate complex). * By sequestering the iron, it prevents the metal from participating in the **Fenton reaction**, thereby halting the production of damaging reactive oxygen species (hydroxyl radicals). * The ferrioxamine complex is then readily excreted by the kidneys into the urine. It does not significantly chelate other essential trace metals or electrolytes (except aluminum).
動物種別の用量
- Severe iron toxicosis · 40 mg/kg IM q4-8 hours · IM · q4-8h · Until urine clears or serum iron levels return to normal · Cat dosages are not well established; extrapolated from general animal doses.
- Severe iron toxicosis · 15 mg/kg/hour · IV · CRI · 2-3 days · Cat dosages are not well established; extrapolated from general animal doses.
- Severe iron toxicosis · 10 mg/kg IM or IV q8h for 24 hours · IM/IV · q8h · 24 hours · Cat dosages are not well established.
- Severe iron toxicosis · 40 mg/kg IM q4-8 hours · IM · q4-8h · Until urine clears or serum iron levels return to normal · Most effective within the first 24 hours. IM route is preferred as too rapid IV administration can cause hypotension and pulmonary edema.
- Severe iron toxicosis · 15 mg/kg/hour · IV · CRI · 2-3 days (until serum iron < 300 microliters/dL or below TIBC) · Initiate ASAP or at least within 12 hours of ingestion. Give as a constant rate infusion. If CRI not possible, give 40 mg/kg IM q4-8h.
- Severe iron toxicosis · 10 mg/kg IM or IV q8h for 24 hours · IM/IV · q8h · 24 hours
- Ferric ion chelator during treatment of cardiac arrest (experimental) · 5-15 mg/kg IV , IM or SC · IV/IM/SC · Single dose or as directed
- Ferric ion chelator during treatment of cardiac arrest (experimental) · 10 mg/kg IV , IM q2h twice, then three times daily for 24 hours · IV/IM · q2h twice, then TID · 24 hours
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
- Severe renal failure (unless dialysis is used to remove the ferrioxamine complex)
有害事象
- Allergic reactions (hives, wheezing)
- Auditory neurotoxicity (with chronic, high-dose therapy)
- Pain or swelling at injection sites
- Gastrointestinal distress
- Hypotension, tachycardia, and convulsions (if given IV too rapidly)
- Pulmonary edema (associated with rapid IV administration)
薬物相互作用
- Prochlorperazine · Concurrent use may cause temporary impairment of consciousness.
- Vitamin C (Ascorbic Acid) · May be synergistic in removing iron, but could lead to increased tissue iron toxicity, especially in cardiac muscle. Use with extreme caution in patients with preexisting cardiac disease.
モニタリング
- Serum iron levels
- Total iron-binding capacity (TIBC)
- Serum ferritin
- Urine color (monitor for clearing of the 'vin rosé' color)
- Blood pressure and heart rate (especially during IV infusion)
- Ophthalmic examinations (if used chronically)
過量投与
Acute overdosage or excessively rapid IV administration can lead to severe hypotension, tachycardia, convulsions, hives, wheezing, and pulmonary edema. Chronic high-dose use may lead to hypocalcemia, thrombocytopenia, and auditory/visual neurotoxicity. Treatment is 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。