美拉索明
Melarsomine
Melarsomine dihydrochloride
別名: Immiticide · Diroban · Melarsomine dihydrochloride
由 VetSheet 獸醫團隊審訂更新於 2026年4月5日本內容以實證獸醫文獻為本
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各物種劑量
🌎 NA — North America🌍 EU — Europe
狗
| 適應症 | 劑量 | 途徑 | 頻次 | 療程 | 地區 |
|---|---|---|---|---|---|
| Heartworm disease (Class I & II) | 2.5 mg/kg deep IM as directed (lumbar epaxial muscles (L3-L5) twice 24 hours apart | IM | q24h for 2 doses | 2 days | 🌎 NA |
| Heartworm disease (Class III) | 2.5 mg/kg deep IM as directed (lumbar epaxial muscles (L3-L5). Strict rest and give all necessary systemic treatment. One month later, give 2.5 mg/kg deep IM as directed (lumbar epaxial muscles (L3-L5) twice 24 hours apart. | IM | Once, then q24h for 2 doses 1 month later | 1 month + 2 days | 🌎 NA |
| Heartworm disease (Alternative Protocol / AHS Treatment of Choice) | 2.5 mg/kg deep IM as directed (lumbar epaxial muscles; L3-L5). Strict rest and give all necessary systemic treatment. One month later, give 2.5 mg/kg deep IM as directed (lumbar epaxial muscles; L3-L5) twice 24 hours apart | IM | Once, then q24h for 2 doses 1 month later | 1 month + 2 days | 🌎 NA |
- Heartworm disease (Class I & II): Use alternating sides with each administration. In 4 months, the regimen may be repeated.
- Heartworm disease (Class III): Requires strict rest.
- Heartworm disease (Alternative Protocol / AHS Treatment of Choice): Treatment of choice regardless of stage of disease due to increased safety and efficacy.
劑量為持牌獸醫專業人員的臨床參考。請務必對照最新藥品說明書及個別病患確認。
概覽
美拉索明（Melarsomine）是一種有機砷化學治療藥物，專門用於治療犬心絲蟲（Dirofilaria immitis）成蟲感染。它對成熟的成蟲和未成熟的（4個月大，L5階段）幼蟲具有高度療效。
臨床要點：雖然美拉索明是唯一獲准的成蟲殺滅劑，但目前美國心絲蟲協會（AHS）強烈建議採用多模式療法。建議在注射美拉索明前1至2個月，先使用大環內酯類藥物（如伊維菌素）和多西環素（Doxycycline）進行預處理。多西環素可消滅心絲蟲賴以生存和繁殖的共生菌（Wolbachia），從而削弱心絲蟲、減少蟲體生物量，並顯著降低蟲體死亡時引發的發炎反應及嚴重的肺血栓栓塞風險。
美拉索明比其前代藥物硫乙胂胺（thiacetarsamide）更安全且更有效，但其安全範圍仍然狹窄，需要精確的劑量和給藥技術。
作用機制
While the exact mechanism of action is not definitively established, as an arsenical compound, melarsomine is believed to exert its parasiticidal effect by binding to sulfhydryl (-SH) groups of essential enzymes within the parasite.
- Enzyme Inhibition → Disrupts cellular respiration and vital metabolic pathways in the parasite.
- Target → Highly effective (90-99%) at killing adult and L5 larval stages of D. immitis in dogs.
- Clearance → Dead worms degrade and are swept into the pulmonary vasculature, where they are eventually cleared by the host's immune system (macrophages).
安全性與警告
禁忌症
- Class IV (very severe) heartworm disease / Caval syndrome
- Cats (reportedly very toxic)
- Intravenous (IV) administration
- Subcutaneous (SC) administration
不良反應
- Injection site reactions (pain, swelling, tenderness, firm nodules)
- Coughing/gagging
- Depression/lethargy
- Anorexia/inappetence
- Excessive salivation
- Fever
- Lung congestion
- Vomiting
- Pulmonary thromboembolism (can be fatal)
- Paresis and paralysis (rare)
注意事項
Low margin of safety; calculate dosages very carefully (do not confuse mg/lb with mg/kg). Administer ONLY via deep IM injection in the lumbar epaxial muscles (L3-L5). Do NOT give IV or SC, as significant toxicity or tissue necrosis may occur. Strict cage rest (2-4 weeks) is mandatory to prevent fatal pulmonary thromboembolism. Older dogs (>8 years) and those with severe pulmonary artery disease are at higher risk for adverse effects. Avoid human exposure; wash hands after use or wear gloves. If human exposure occurs, contact a physician.
藥物相互作用
Has been shown not to reduce adverse effects and may complicate therapy; use is not recommended.
Drugs that have similar adverse effects (e.g., depression) may cause additive adverse effects or increase their incidence when used with melarsomine.
監測
- Clinical efficacy
- Adverse effects (observe dogs for 24 hours after the last injection)
- Signs of pulmonary thromboembolism (coughing, hemoptysis, tachypnea, dyspnea)
- Injection site reactions
藥物動力學
半衰期
吸收
Rapidly absorbed after IM injection in dogs; time to peak plasma concentration is about 11 minutes.
分佈
The apparent volume of distribution is about 0.7 L/kg.
排除
Terminal half-life is approximately 3 hours.
過量
There is a low margin of safety with melarsomine.
- 3X dose (7.5 mg/kg) in healthy dogs causes respiratory inflammation and distress, excessive salivation, restlessness, panting, vomiting, edema, tremors, lethargy, ataxia, cyanosis, stupor, and death.
- 2X dose in infected dogs has caused diarrhea, excessive salivation, restlessness, panting, vomiting, and fever.
- Treatment: Dimercaprol (BAL in Oil) may be considered to treat melarsomine overdoses, though it may reduce the clinical efficacy of the melarsomine.
可用產品
劑型
- Powder for injection
獸醫用
- Melarsomine Dihydrochloride Powder for Injection: 50 mg/vial (Immiticide)
各地核准狀態
暫無法規資料: 🇺🇸 US · 🇪🇺 EU · 🇬🇧 UK · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
儲存與穩定性
The unreconstituted powder should be stored upright at room temperature. Reconstitute with 2 mL of the provided sterile water for injection (yields 25 mg/mL). Once reconstituted, keep in the original container and refrigerate for up to 24 hours. Do not freeze. Do not mix with any other drug.
飼主須知
極度重要警告：必須嚴格限制活動（關籠休息）。
- 限制運動：當心絲蟲成蟲死亡時，蟲體會碎裂並隨血流進入肺部。任何心跳加快的情況（如散步、玩耍或興奮）都會將這些蟲體碎片推入肺部更深處的微小血管，導致可能致命的阻塞（肺血栓栓塞）。在治療後的數週內，您的愛犬必須嚴格限制在籠子或小房間內。
- 注射部位疼痛：藥物是經由背部肌肉深層注射給予。您的愛犬可能會感到疼痛、不願走動，或在注射部位出現小硬塊，這些都是正常現象。
- 觀察重點：密切觀察愛犬是否有咳嗽、作嘔、發燒、嗜睡或食慾不振的情況。
- 緊急徵兆：如果您的愛犬出現嚴重呼吸困難、牙齦蒼白或發紺（發紫），或突然倒下，請立即尋求緊急獸醫協助。
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