エタンブトール
エタンブトールは合成の静菌性抗マイコバクテリア薬であり、主に多剤併用療法（カクテル療法）の一部として、難治性のマイコバクテリア感染症（結核菌、ウシ型結核菌、マイコバクテリウム・アビウム・コンプレックスなど）の治療に使用されます。 **臨床上のポイント：** 段階的な耐性獲得を避けるため、単独療法は厳格に避けられます。通常、リファンピシンやイソニアジドなどの薬剤と併用されます。 > **公衆衛生上の重要な注意：** 人獣共通感染症の重大な潜在的リスクがあり、特に家庭内の免疫不全者にとって危険であるため、獣医療におけるこれらの感染症の治療には大きな議論があります。
作用機序: Ethambutol is active only against actively dividing mycobacteria. Mechanistically, it inhibits the enzyme **arabinosyl transferase** → disrupts the synthesis of arabinogalactan → prevents the incorporation of **mycolic acid** into the mycobacterial cell wall. This disruption increases cell wall permeability, which allows other antimycobacterial drugs (like rifampin or isoniazid) to penetrate the cell more effectively. It also interferes with RNA synthesis. It has no appreciable activity against other non-mycobacterial bacteria or fungi.
動物種別の用量
- Treatment of feline tuberculosis (resistant cases) · 15 mg/kg PO once daily · PO · once daily · Not specified · Considered if resistance develops to initial therapy. Used in combination with rifampin and isoniazid.
- Treatment of M. avium infections in caged birds (Protocol 1) · 20 mg/kg PO q12h · PO · q12h · 6-12 months · Used with Ciprofloxacin/Enrofloxacin, Clofazimine, and Cycloserine.
- Treatment of M. avium infections in caged birds (Protocol 2) · 30 mg/kg PO once daily · PO · once daily · 6-12 months · Used with Clofazimine and Rifampin.
- Treatment of M. avium infections in caged birds (Protocol 3) · 30 mg/kg PO once daily · PO · once daily · 6-12 months · Used with Ciprofloxacin/Enrofloxacin and Rifampin/Rifabutin.
- Avian mycobacteriosis · 30-85 mg/kg PO once daily · PO · once daily · 9-12 months · Used with Rifabutin, Clarithromycin, and Enrofloxacin.
- Treatment of disseminated M. tuberculosis · 10-25 mg/kg PO once daily · PO · once daily · More than 9 months · Used in combination with rifampin (5-10 mg/kg PO q12-24h) and isoniazid (10-20 mg/kg PO once daily). May also add pyrazinamide (ineffective for M. bovis).
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
- Patients with a history of prior hypersensitivity reactions to ethambutol
有害事象
- Optic neuritis (decreased visual acuity, usually reversible)
- CNS degenerative changes (with prolonged use)
- Myocardial toxicity (at high doses)
- Depigmentation of the tapetum lucidum
- Bacterial or fungal overgrowth (due to prolonged multi-drug antimicrobial therapy)
薬物相互作用
- Aluminum-containing antacids · Can reduce oral absorption of ethambutol; separate dosing by at least 4 hours if both are necessary
モニタリング
- Clinical efficacy
- Visual function (periodic monitoring with long-term therapy)
- Liver function
- Renal function
- CBC
- Monitor for fungal or bacterial overgrowth infections
過量投与
Very limited veterinary information exists. In humans, acute overdoses of >10 grams have caused **optic neuritis**. Other adverse effects noted with human overdoses include CNS effects (confusion, visual hallucinations), abdominal pain, nausea, fever, and headache. Treatment is supportive.
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。