青黴素V鉀 (盤尼西林V鉀)
**青黴素V鉀**是一種天然的窄效**β-內醯胺類抗生素**。與青黴素G相比，它對胃酸的抵抗力更強，因此在單胃動物中口服吸收更好，常用於治療輕至中度的敏感性細菌感染。
作用機制: Penicillin V is a **time-dependent, bactericidal** antibiotic. It works by targeting the bacterial cell wall: 1. Binds to specific **penicillin-binding proteins (PBPs)** (such as **transpeptidases** and **carboxypeptidases**) located inside the bacterial cytoplasmic membrane. 2. Inhibits the third and final stage of bacterial cell wall synthesis by preventing the cross-linking of **peptidoglycan** strands. 3. This leads to a defective, osmotically unstable cell wall (spheroplast) → **cell lysis** and death. *Note: Like all beta-lactams, it is only effective against actively growing and dividing bacteria.*
各物種劑量
- Susceptible infections · 5.5-11 mg/kg · PO · q6-8h
- Soft tissue infections · 10 mg/kg · PO · q8h · 7 days
- Susceptible infections · 110,000 U/kg (68.75 mg/kg) · PO · q8h · May yield supra-optimal levels against uncomplicated infections by sensitive organisms
- Susceptible infections · 110,000 U/kg · PO · q6-12h
- Susceptible infections · 5.5-11 mg/kg · PO · q6-8h
- Soft tissue infections · 10 mg/kg · PO · q8h · 7 days
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
- Oral administration in patients with septicemia, shock, or grave illness (due to delayed/diminished GI absorption)
- Use in sensitive species (snakes, birds, turtles, guinea pigs, chinchillas) without extreme caution
不良反應
- GI effects (anorexia, vomiting, diarrhea)
- Hypersensitivity reactions (rashes, fever, eosinophilia, anaphylaxis)
- Antibiotic-associated diarrhea and superinfections (due to altered gut flora)
- Neurotoxicity (e.g., ataxia in dogs) at very high doses
- Elevated liver enzymes
- Tachypnea, dyspnea, edema, and tachycardia (reported in dogs)
藥物相互作用
- Aminoglycosides · In vitro synergism against certain bacteria; however, mixing them in the same syringe or fluid line can cause physical inactivation of the aminoglycoside.
- Bacteriostatic Antibiotics (e.g., chloramphenicol, erythromycin, tetracyclines) · May antagonize the bactericidal activity of penicillins, which require actively dividing bacteria to be effective.
- Methotrexate · Penicillins may decrease the renal elimination of methotrexate, potentially increasing its toxicity.
- Probenecid · Competitively blocks the renal tubular secretion of penicillins, significantly increasing their serum levels and half-lives.
監測
- Clinical efficacy (resolution of infection signs)
- Adverse GI effects
- Signs of hypersensitivity or allergic reaction
過量
Acute oral overdoses are unlikely to cause significant problems other than **gastrointestinal distress** (vomiting, diarrhea). In humans, massive overdoses of parenteral penicillins (especially in patients with renal impairment) have induced **CNS effects** and seizures. Treatment is supportive.
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。