泰樂菌素
泰樂菌素（Tylosin）是一種由弗氏鏈黴菌（*Streptomyces fradiae*）自然產生的巨環類抗生素。雖然主要獲FDA核准用於家畜（牛和豬）的呼吸道與腸道感染，但它在小動物醫學中是治療**泰樂菌素反應性腹瀉（TRD）**、慢性結腸炎和炎症性腸病（IBD）的重要藥物。 **臨床重點：** * **微生態調節：** 在犬隻中，泰樂菌素對TRD特別有效。這可能是因為它能調節腸道微生物群（特別是促進有益的腸球菌 *Enterococcus* spp.）以及其免疫調節作用，而不僅僅是透過直接的抗菌特性。 * **淚痕管理：** 臨床上偶爾被用於減少犬隻（如馬爾濟斯、貴賓犬）的淚痕（epiphora），其機制可能與結合紫質或改變正常菌叢有關，但基於抗生素管理的考量，此用途仍具爭議。 * **FIP：** 曾有傳聞將其作為免疫調節劑用於患有貓傳染性腹膜炎（FIP）的貓咪，但相關證據有限。
作用機制: Tylosin shares a mechanism of action with erythromycin: * **Antimicrobial Action:** Binds reversibly to the **50S ribosomal subunit** of susceptible bacteria → inhibits translocation of peptides → prevents protein synthesis. It is primarily **bacteriostatic**, but can be bactericidal at high concentrations. * **Spectrum of Activity:** Effective against Gram-positive bacteria, *Mycoplasma*, *Chlamydia*, and some Gram-negative anaerobes (e.g., *Clostridium perfringens*). * **Immunomodulation & Probiotic Effect:** Alters cell-mediated immunity. In dogs, it specifically increases jejunal concentrations of *Enterococcus faecalis*, which acts as a probiotic to stabilize the gut barrier and resolve chronic diarrhea.
各物種劑量
- Adjunctive treatment of IBD · 10 mg/kg · PO · TID · 21 days · Therapeutic trial to evaluate efficacy
- IBD or diarrheas caused by C. perfringens · 20-40 mg/kg · PO · BID
- IBD · 40 mg/kg · PO · q12h
- Clostridial colitis · 10-40 mg/kg · PO · BID · Practically: 1/16 tsp 2-3x/day. Chronic cases often controlled with 1 treatment every 2-3 days.
- Susceptible infections · 7-15 mg/kg · PO · q12-24h
- Susceptible infections · 8.8 mg/kg · IM · BID · up to 3 days · Continue 24h after symptoms stop. Max 5 mL/site.
- Susceptible infections · 5-10 mg/kg · IM · up to 3 days · Until 24h after remission
- Susceptible infections · 12.5 mg/kg · IM · q12h · Tylosin base injectable
- Susceptible infections · 10 mg/kg · PO · SID to BID
- Susceptible infections · 10 mg/kg · up to 5 days
給藥途徑
禁忌症
- Hypersensitivity to tylosin or other macrolide antibiotics
- Horses (causes severe and potentially fatal dysbiosis/diarrhea)
- No specific contraindications available in the monograph
不良反應
- Pain and local reactions at IM injection sites
- Mild GI upset (anorexia, diarrhea) in small animals
- Severe/fatal diarrhea in horses (any route)
- Severe diarrhea in ruminants (PO)
- Swine: edema of rectal mucosa, mild anal protrusion with pruritus, erythema, and diarrhea
- Gastrointestinal disturbances
- Pain at the site of injection
藥物相互作用
- Digoxin · May increase digoxin blood levels, potentially resulting in toxicity
監測
- Clinical efficacy (resolution of diarrhea or infection)
- Adverse effects (GI upset, injection site reactions)
- Clinical response (resolution of diarrhea or infection)
- Injection site for pain or inflammation
過量
Tylosin is relatively safe in most overdose situations. * **Dogs:** Tolerate oral doses up to 800 mg/kg. Long-term (2-year) oral administration of up to 400 mg/kg produced no organ toxicity. * **Pigs:** LD50 is >5 g/kg PO, and ~1 g/kg IM. However, shock and death have been reported in baby pigs overdosed with tylosin.
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