ポナズリル
ポナズリル（Ponazuril）は、主に *Sarcocystis neurona* によって引き起こされる馬原虫性脊髄脳炎（EPM）の治療に使用される、FDA承認のトリアジン系抗原虫薬です。 **臨床のポイント：** - トルトラズリルの活性代謝物です。 - 馬用に承認されていますが、その有効性と比較的安全なプロファイルから、犬猫、エキゾチックアニマル、反芻動物のコクシジウム症、ネオスポラ症、トキソプラズマ症の治療にオフラベルで広く使用されています。 - 血液脳関門を通過するため、中枢神経系の原虫感染症に有効です。
作用機序: Ponazuril targets the **apicoplast** (plastid body), an essential organelle found specifically in members of the Apicomplexa phylum (which includes *Sarcocystis*, *Toxoplasma*, *Neospora*, and *Eimeria*). Inhibition of the apicoplast → Disruption of the organism's ability to synthesize essential fatty acids and amino acids → **Protozoal death** (cidal activity).
動物種別の用量
- Neosporosis or Toxoplasmosis · 7.5-15 mg/kg PO once daily · PO · q24h · 28 days · Dose extrapolated between doses for horses and mice.
- Coccidiosis · 20 mg/kg PO daily · PO · q24h · 3 days · Must be compounded for administration in kittens or cats. Associated with rapid resolution of diarrhea.
- Equine Protozoal Myeloencephalitis (EPM) · 5 mg/kg PO once daily · PO · q24h · 28 days · See package insert for specific dosing instructions.
- Cryptosporidium respiratory disease (Falcons) · 20 mg/kg PO once daily · PO · q24h · 7 days · Given as a compounded suspension.
- Adjunctive treatment of Eimeria species (Rabbits) · 20 mg/kg PO q24h · PO · q24h · 7 days
- Eimeria macusaniensis (Camelids/Crias) · 20 mg/kg PO once daily · PO · q24h · 3 days · Dilute paste to 100 mg/mL before administration (e.g., 40g paste + distilled water to 60g total).
- Neosporosis or Toxoplasmosis · 7.5-15 mg/kg PO once daily · PO · q24h · 28 days · Dose extrapolated between doses for horses and mice.
- Coccidiosis · 15-30 mg/kg PO once or repeated after 7-10 days · PO · once or repeated after 7-10 days · 1-2 doses · Anecdotal
- Coccidians (Bearded dragons) · 30 mg/kg PO twice 48 hours apart · PO · q48h · 2 doses
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
- No absolute contraindications noted, but other causes of ataxia should be ruled out before treating for EPM.
有害事象
- Blisters on nose and mouth
- Rash or hives
- Diarrhea or loose feces
- Mild colic
- Seizures (rare)
- Keratoconjunctivitis sicca (KCS) in dogs (especially predisposed breeds or at high doses)
モニタリング
- Clinical efficacy and resolution of neurological or gastrointestinal signs
- Tear production (Schirmer Tear Test) in dogs, especially predisposed breeds
過量投与
In horses, daily doses of up to 30 mg/kg (6X the normal dose) primarily caused loose feces. Moderate edema of the uterine epithelium was noted on histopathology for female horses receiving the 6X dose. In dogs, overdose quantities have been associated with the development of Keratoconjunctivitis sicca (KCS).
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。