雙氯西林
雙氯西林（Dicloxacillin）是一種口服、窄效的**抗青黴素酶**（異惡唑基）青黴素。在獸醫學中，主要用於口服治療由產生β-內醯胺酶的葡萄球菌引起的軟組織、皮膚和骨骼感染。 > **臨床要點**：由於其龐大的異惡唑基側鏈，它能抵抗葡萄球菌β-內醯胺酶的降解。然而，其在犬隻體內的口服生物利用度差（約23%）且半衰期短，需要頻繁給藥（每6-8小時一次），這可能影響飼主的依從性。由於這些藥代動力學的限制，小動物臨床上通常更傾向使用其他抗葡萄球菌藥物（如頭孢氨苄或阿莫西林-克拉維酸）。
作用機制: Dicloxacillin is a **bactericidal** beta-lactam antibiotic. * It binds to specific **Penicillin-Binding Proteins (PBPs)** located inside the bacterial cell wall. * This binding inhibits the third and final stage of bacterial cell wall synthesis → blocks the cross-linking of peptidoglycan. * The weakened cell wall leads to the activation of autolysins → **cell lysis** and bacterial death. * Its bulky side chain prevents the beta-lactam ring from being hydrolyzed by staphylococcal penicillinase.
各物種劑量
- Localized soft tissue infections or skin infections caused by susceptible (non-beta-lactamase producers) bacteria · 25 mg/kg PO q6h · PO · q6h · 14-84 days
- Localized soft tissue infections or skin infections caused by susceptible (non-beta-lactamase producers) bacteria · 25 mg/kg PO q6h · PO · q6h · 14-84 days
- Dermatologic infections · 22 mg/kg PO q8h · PO · q8h
- Recurrent skin infections · 20-30 mg/kg PO three times daily · PO · q8h · Food may decrease absorption
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
- Hypersensitivity to penicillins
- Septicemia, shock, or other grave illnesses (oral absorption may be significantly delayed or diminished)
不良反應
- Anorexia
- Vomiting
- Diarrhea
- Antibiotic-associated diarrhea (superinfections)
- Hypersensitivity reactions (rashes, fever, eosinophilia, anaphylaxis)
- Neurotoxicity (ataxia at very high doses)
- Elevated liver enzymes
- Tachypnea
- Dyspnea
- Edema
- Tachycardia
藥物相互作用
- Aminoglycosides · In vitro evidence of synergism with dicloxacillin against S. aureus strains; however, penicillins can inactivate aminoglycosides in vitro, so do not mix in the same syringe/fluid line.
- Cyclosporine · Dicloxacillin may reduce cyclosporine levels.
- Probenecid · Competitively blocks the tubular secretion of dicloxacillin, thereby increasing serum levels and serum half-lives.
- Tetracyclines · Theoretical antagonism; concurrent use is usually not recommended.
- Warfarin · Dicloxacillin may cause decreased warfarin efficacy.
監測
- Clinical efficacy (resolution of infection)
- Toxic clinical signs (GI upset, hypersensitivity)
過量
Acute oral penicillin overdoses are unlikely to cause significant problems other than **GI distress** (vomiting, diarrhea). In humans, very high dosages of parenteral penicillins, especially in patients with renal disease, have induced **CNS effects** (neurotoxicity).
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。