氯唑西林 (Cloxacillin)
氯唑西林是一種**窄效、耐青黴素酶的青黴素類抗生素**（異噁唑青黴素）。主要用於對抗產生青黴素酶的革蘭氏陽性球菌，特別是**葡萄球菌 (Staphylococcus spp.)**。在美國，目前僅有乳房內灌注劑型用於治療或預防乳牛的乳腺炎。口服劑型已不再於美國市場銷售。
作用機制: Cloxacillin is a bactericidal beta-lactam antibiotic. Binds to **Penicillin-Binding Proteins (PBPs)** → inhibits peptidoglycan cross-linking → disrupts bacterial cell wall synthesis → cell lysis and death. **Mechanistic Pearl:** The bulky isoxazolyl side chain sterically hinders staphylococcal **beta-lactamases**, preventing the enzymatic hydrolysis of the beta-lactam ring that normally inactivates natural penicillins.
各物種劑量
- Susceptible infections · 20-40 mg/kg PO or IM q6-8h · PO/IM · q6-8h
- Staph. pyoderma, diskospondylitis, osteoarthritis or skin infections · 10-15 mg/kg PO q6h for 14-84 days · PO · q6h · 14-84 days
- Systemic infections, bacteremia · 10-40 mg/kg PO q6-8h for 7-14 days · PO · q6-8h · 7-14 days
- Ocular infections · Apply 1/10 of a tube (0.3 g) · topical · q24h · Specifically for beta-lactamase-producing Staphylococcus
- Mastitis (treatment or prophylaxis) caused by susceptible organisms - Lactating cow · After milking out and disinfecting teat, instill contents of syringe; massage. · Intramammary · q12h · 3 total doses · Using lactating cow formula (Dari-Clox)
- Mastitis (treatment or prophylaxis) caused by susceptible organisms - Dry (non-lactating) cows · After last milking (or early in the dry period), instill contents of syringe and massage into each quarter. · Intramammary · Once · Using dry cow formula (benzathine)
- Susceptible infections · 20-40 mg/kg PO q8h · PO · q8h · Oral dosage forms are no longer available commercially in the USA
- Staph. pyoderma, diskospondylitis, osteoarthritis or skin infections · 10-15 mg/kg PO q6h for 14-84 days · PO · q6h · 14-84 days
- Systemic infections, bacteremia · 10-40 mg/kg PO q6-8h for 7-14 days · PO · q6-8h · 7-14 days
- Ocular infections · Apply 1/10 of a tube (0.3 g) · topical · q24h · Specifically for beta-lactamase-producing Staphylococcus
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。
給藥途徑
禁忌症
- Known hypersensitivity to penicillins
- Known hypersensitivity to penicillins or cephalosporins
不良反應
- Hypersensitivity reactions (rashes, fever, anaphylaxis)
- Eosinophilia
- Neutropenia
- Agranulocytosis
- Thrombocytopenia
- Leukopenia
- Anemias
- Lymphadenopathy
- Hypersensitivity reactions
- Local irritation (ophthalmic)
監測
- Clinical efficacy (resolution of infection/mastitis)
- Signs of hypersensitivity or toxicity
- Resolution of clinical signs of ocular infection
- Signs of local irritation or hypersensitivity
過量
Overdosage of intramammary infusions is unlikely to pose much systemic risk to the patient. > **Note:** Excessive dosing may prolong required withdrawal times for milk and meat in food-producing animals.
VetSheet 藥物參考供持牌獸醫專業人員作臨床決策輔助之用,不能取代專業判斷或廠方最新藥品說明書。