プリマキン
プリマキンは8-アミノキノリン系の**抗原虫薬**であり、獣医療においては主に猫の***Babesia felis***（バベシア・フェリス）感染症の第一選択薬として使用されます。 - **臨床上のポイント**: 臨床症状の管理には極めて有効ですが、通常、寄生虫を完全に排除（感染の無菌化）することはできず、再発により反復治療が必要になる場合があります。 - 犬の***Hepatozoon canis***（ヘパトゾーン）や鳥類の***Plasmodium spp.***（マラリア原虫）に対しても有用な可能性があります。 - **注意**: 猫における治療指数（安全域）は非常に狭いため、用量には細心の注意が必要です。
作用機序: The exact antiprotozoal mechanism of action is not fully elucidated. - It is believed to **bind and alter protozoal DNA**. - **Pharmacological Pearl**: As an 8-aminoquinoline, it likely interferes with the parasite's mitochondrial function. It generates **reactive oxygen species (ROS)** → disrupts electron transport → causes severe cellular and oxidative damage to the protozoa.
動物種別の用量
- Babesia felis · 0.5 mg (as base)/kg PO once daily · PO · q24h · 1-3 days · Dose is for primaquine base.
- Babesia felis · 1 mg (total dose per cat) primaquine phosphate PO every 36 hours for 4 treatments, then 1 mg (total dose) per cat every 7 days for 4 treatments · PO · q36h then q7d · 4 treatments each · The drug does not sterilize the infection.
- Babesia felis · Primaquine phosphate 1 mg/kg IM one time · IM · once · 1 time · IM dosage form must be compounded.
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 to primaquine
- Concurrent use of bone marrow suppressant medications
- Patients susceptible to granulocytopenia (e.g., lupus, rheumatoid arthritis)
- Glucose-6-Phosphate Dehydrogenase (G-6-PD) deficiency
- Pregnancy
- Lactation
有害事象
- Vomiting (most common in cats)
- Nausea
- Myelosuppression
- Methemoglobinemia
- Hemolysis
薬物相互作用
- Quinacrine · May potentiate the toxicity of one another; use of primaquine within 3 months of quinacrine is not recommended.
- Bone Marrow Depressants (e.g., amphotericin B, azathioprine, chloramphenicol, antineoplastics) · Concurrent use may cause an increased risk for toxicity and severe myelosuppression.
- Hemolytic Drugs (e.g., acetohydroxamic acid, sulfonylureas, quinidine, sulfonamides) · Concurrent use may cause an increased risk for toxicity and hemolysis.
モニタリング
- CBC (mandatory, monitor weekly while treating)
- Improved clinical signs (increased appetite and body weight)
- Improvement in anemia
過量投与
> **CRITICAL**: In cats, dosages **greater than 1 mg/kg** can be lethal. - **Management**: Overdoses should initially be handled aggressively using standardized protocols for removal of the drug from the gut (emesis, activated charcoal) to prevent absorption. - Provide intensive supportive care for potential methemoglobinemia, hemolysis, and myelosuppression. - Because of the potential seriousness of overdoses, it is strongly recommended to contact an animal poison control center for guidance immediately.
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。