哌拉西林鈉
哌拉西林是一種**廣效性醯胺基青黴素 (acylaminopenicillin)** 抗生素，主要用於治療嚴重或具抗藥性的細菌感染。 * **廣效抗菌譜**：對許多需氧及厭氧的革蘭氏陽性與陰性菌具有擴展的抗菌範圍，特別是包含許多**綠膿桿菌 (Pseudomonas aeruginosa)** 及腸桿菌科的菌株。 * **臨床應用**：雖然在獸醫學的經驗相對有限，但在等待細菌培養與藥物敏感性試驗結果前，對於重症病患的經驗性療法，或針對混合需氧/厭氧菌及革蘭氏陰性菌污染的手術預防，具有極高的價值。 * **對 β-內醯胺酶的敏感性**：與其他氨基青黴素一樣，單獨使用哌拉西林容易被 β-內醯胺酶破壞。因此常與 β-內醯胺酶抑制劑（如他唑巴坦 tazobactam）合併使用以克服抗藥性。 * **給藥方式**：口服吸收不佳，必須以腸胃外途徑（靜脈注射、肌肉注射或皮下注射）給藥。
作用機制: Piperacillin is a **bactericidal** time-dependent antibiotic. * It binds to specific **Penicillin-Binding Proteins (PBPs)** (especially PBP-3) located inside the bacterial cell wall. * Binding to PBPs → inhibition of the third and final stage of bacterial cell wall synthesis (cross-linking of **peptidoglycan** strands). * This weakens the cell wall → activation of bacterial autolysins → **cell lysis and death**. * *Note*: Its efficacy is highly dependent on the amount of time the drug concentration remains above the Minimum Inhibitory Concentration (MIC) of the target pathogen.
各物種劑量
- For bacteremia with or without endocarditis · 30 mg/kg IV q6h for 7-14 days · IV · q6h · 7-14 days
- For respiratory infections · 25-50 mg/kg IV q8h · IV · q8h
- For susceptible infections · 15-50 mg/kg IV or IM q6-12h · IV/IM · q6-12h
- For Bordetella avium infections · 150 mg/kg IM q8-12h · IM · q8-12h · minimum treatment period is two weeks
- For susceptible infections · 100 mg/kg IM two to three times daily · IM · BID-TID
- For empirical treatment in Psittacines of gram-negative bacterial infections · 100 mg/kg IM 3-4 times a day if immunocompetent; 4 times a day if immunocompromised · IM · TID-QID
- For bacteremia with or without endocarditis · 30 mg/kg IV q6h for 7-14 days · IV · q6h · 7-14 days
- For respiratory infections · 25-50 mg/kg IV q8h · IV · q8h
- For systemic treatment of otitis media or proliferative otitis externa complicated by gram-negative (especially Pseudomonas) bacteria · 20 mg/kg SC three times daily · SC · TID
給藥途徑
禁忌症
- Patients with documented hypersensitivity to beta-lactam antibiotics (penicillins, cephalosporins)
不良反應
- Hypersensitivity reactions (allergic reactions)
- Local tissue irritation, pain at IM injection site
- Thrombophlebitis (with IV administration)
- Antibiotic-associated diarrhea (due to alterations in gut flora)
- Coagulation abnormalities (rare, mostly in renal failure)
- Neurotoxicity/seizures (at very high doses or in renal impairment)
- Clostridium difficile superinfections (rare)
藥物相互作用
- Aminoglycosides (amikacin, gentamicin, tobramycin) · Synergistic against certain bacteria in vitro, but penicillins can chemically inactivate aminoglycosides in vivo (especially in renal failure or at massive doses). Do not mix in the same syringe/bag.
- Anticoagulants (heparin, warfarin) · Piperacillin may rarely affect platelets; increased monitoring of coagulation parameters is suggested.
- Methotrexate · Piperacillin may increase methotrexate serum levels.
- Probenecid · Reduces renal tubular secretion of piperacillin, maintaining higher systemic levels for longer periods.
- Vecuronium · Piperacillin may prolong neuromuscular blockade.
監測
- Clinical efficacy (resolution of clinical signs, fever)
- White blood cell count (WBC)
- Renal function (if prolonged use or pre-existing impairment)
- Coagulation parameters (if on concurrent anticoagulants or high doses)
過量
Single overdoses are unlikely to pose much risk. * **Massive Overdoses**: May cause vomiting, diarrhea, or neurotoxicity (seizures). * **Chronic High Doses**: Dogs receiving up to 800 mg/kg/day of piperacillin/tazobactam for 6 months demonstrated no serious toxic effects. Doses ≥400 mg/kg/day caused transient liver effects (glycogen granules in cytoplasm, increased smooth endoplasmic reticulum) that mostly reversed after one month. * **Treatment**: Supportive care. Monitor renal and neurological status.
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。