盤尼西林 G / 青黴素 G
Penicillin G
Benzylpenicillin
別名: Bicillin C-R · Masti-Clear · Permapen · Pfizerpen · Go-Dry · crystalline penicillin G · APPG · aqueous penicillin · procaine benzylpenicillin
由 VetSheet 獸醫團隊審訂更新於 2026年4月5日本內容以實證獸醫文獻為本
經審核的 v13 劑量證據
結構化劑量計算證據Susceptible infections (extra-label): Penicillin G procaine
須由已驗證獸醫確認
- q12-24h
NA
必須一併考量的臨床脈絡 (4)
- NOTE: Label dosages of penicillin have been unchanged for decades and may result in marked underdosing based on current understanding of antibiotic therapy. Although consideration of the label recommendations is required, present-day recommended dosing regimens should be used.
- ■ Because penicillins usually have minimal toxicity associated with their use, monitoring for efficacy is usually all that is required unless toxic signs develop. Serum concentrations and therapeutic drug monitoring are not routinely done with these agents.
- Penicillin G procaine should be stored at 2°C to 8°C (36°F-46°F); avoid freezing. Penicillin G benzathine should be stored at 2°C to 8°C (36°F-46°F).
- Penicillin G sodium and potassium powder for injection can be stored at room temperature (15°C-30°C [59°F-86°F]). After reconstituting, the injectable solution is stable for 7 days when kept refrigerated (2°C-8°C [36°F-46°F]) and for 24 hours at room temperature.
劑量為合格獸醫專業人員的臨床參考。請務必對照最新仿單及個別病患確認。
概覽
盤尼西林 G (Penicillin G)（苄青黴素）是一種窄效的天然β-內醯胺類抗生素，提取自Penicillium chrysogenum。它對大多數革蘭氏陽性需氧菌（如鏈球菌、不產青黴素酶的葡萄球菌）、部分革蘭氏陰性菌（如巴斯德桿菌）以及許多厭氧菌（如梭狀芽孢桿菌）具有高度療效。
臨床要點： 盤尼西林 G 的鹽類形式決定了其給藥途徑與藥代動力學特徵：
- 水性鹽類（鈉鹽或鉀鹽）： 專供靜脈 (IV) 或肌肉 (IM) 注射。能迅速達到高血清峰值濃度，但半衰期極短，需要頻繁給藥（例如每 4-6 小時一次）。
- 長效儲庫型鹽類（普魯卡因和苄星）： 配製為懸浮液，僅限肌肉 (IM) 或皮下 (SC) 注射（嚴禁靜脈注射）。普魯卡因 (Procaine) 可提供持續 12-24 小時的儲庫效應，而苄星 (Benzathine) 則提供可維持數天的極低且延長的藥物濃度。
盤尼西林 G 容易被許多葡萄球菌和革蘭氏陰性腸道菌產生的 β-內醯胺酶（青黴素酶）分解而失效。
作用機轉
Penicillin G is a time-dependent bactericidal antibiotic.
- It covalently binds to Penicillin-Binding Proteins (PBPs) located on the inner membrane of the bacterial cell wall.
- This binding → inhibits the transpeptidation enzyme responsible for cross-linking peptidoglycan strands.
- Failure of cell wall synthesis → activation of autolytic enzymes within the cell wall → osmotic lysis and bacterial death.
Because it targets cell wall synthesis, it is most effective against actively dividing bacteria.
安全性與警告
禁忌症
- Known hypersensitivity to penicillins or cephalosporins
- Intravenous administration of Procaine or Benzathine suspension formulations
- Oral administration in horses and hindgut fermenters (rabbits, guinea pigs) due to risk of fatal dysbiosis (unless specifically indicated, e.g., calves with clostridial enteritis)
不良反應
- Hypersensitivity reactions (anaphylaxis, urticaria, rash)
- Gastrointestinal upset (anorexia, vomiting, diarrhea) with oral use
- Procaine toxicity (CNS excitement, seizures) in small birds and horses if inadvertently given IV
- Pain or tissue reaction at IM injection sites
注意事項
Use cautiously in small birds as procaine penicillin may cause procaine toxicity. Do not use oral penicillin therapy in horses for systemic infections (e.g., botulism). Ensure repository forms (procaine/benzathine) are never administered intravenously. Monitor for hypersensitivity reactions. High doses of Penicillin G Potassium given rapidly IV can cause hyperkalemia and cardiac arrhythmias.
藥物交互作用
May antagonize the bactericidal activity of penicillins, which require actively dividing cells to be effective.
In vivo synergy against certain bacteria; however, physically incompatible if mixed in the same syringe or IV line (inactivation of the aminoglycoside).
Competitively inhibits renal tubular secretion of penicillins, significantly prolonging their half-life and increasing serum concentrations.
監測
- Clinical efficacy (resolution of infection signs)
- Signs of toxicity or hypersensitivity (anaphylaxis, rash)
- Electrolytes (if using high doses of Na or K salts IV)
藥物動力學
半衰期
吸收
Oral absorption is generally poor and variable due to degradation by gastric acid. Aqueous salts (Na/K) are rapidly absorbed after IM/SC injection. Procaine and benzathine salts are slowly absorbed from IM injection sites, providing prolonged but lower serum concentrations.
分佈
Widely distributed to most tissues (lungs, kidneys, muscle, bone). Poor penetration into the central nervous system (CNS), eye, and prostate unless severe inflammation is present. Crosses the placenta.
代謝
Minimal hepatic metabolism.
排除
Rapidly excreted primarily unchanged in the urine via active renal tubular secretion and glomerular filtration.
過量
Because penicillins usually have minimal toxicity associated with their use, monitoring for efficacy is usually all that is required unless toxic signs develop.
Clinical Pearl: Massive overdoses, particularly of aqueous salts given rapidly IV, can lead to neuromuscular hypersensitivity, seizures, or electrolyte imbalances (hyperkalemia with potassium salt, hypernatremia with sodium salt). Treatment is supportive.
可用產品
劑型
- Powder for injection (Potassium or Sodium salts)
- Suspension for injection (Procaine or Benzathine salts)
- Oral tablets and powder for solution
- Intramammary infusion syringes
獸醫用
- Penicillin G Procaine Injection 300,000 Units/mL
- Penicillin G Procaine Mastitis Syringes 100,000 Units/mL (Go-Dry, Masti-Clear)
- Penicillin G Benzathine 150,000 Units/mL with Penicillin G Procaine 150,000 Units/mL Injection
人用標示
- Penicillin G (Aqueous) Sodium Powder for Injection: 5,000,000 Units & 20,000,000 Units
- Penicillin G (Aqueous) Potassium Injection: 1,000,000 Units, 2,000,000 Units & 3,000,000 Units
- Penicillin G Procaine Injection: 600,000 Units/vial & 1,200,000 Units/vial
- Penicillin G Benzathine Injection: 600,000, 1,200,000, & 2,400,000 Units/dose
- Penicillin G Benzathine/Penicillin G Procaine IM Injection (Bicillin C-R)
各地核准狀態
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儲存與穩定性
Penicillin G sodium and potassium powders should be protected from moisture. Oral powder for solution: store at room temperature before mixing; after reconstituting, refrigerate (2-8°C) and discard after 14 days. Injectable Na/K solutions: stable for 7 days refrigerated (2-8°C) and 24 hours at room temperature. Procaine and Benzathine suspensions should be stored at 2-8°C; avoid freezing.
飼主須知
- 給藥方式： 口服盤尼西林應在空腹時給予（飯前 1 小時或飯後 2 小時），以達到最佳吸收效果。如果您的寵物出現腸胃不適（嘔吐、食慾不振），可以與少量食物一起餵食。
- 遵循醫囑： 即使您的寵物看起來已經完全康復，也必須嚴格按照指示完成整個療程。提早停藥可能會導致細菌產生抗藥性。
- 過敏反應： 請密切觀察是否有過敏反應的跡象，例如面部腫脹、蕁麻疹、皮疹或呼吸困難。如果出現這些情況，請立即聯繫您的獸醫師。
- 注射部位： 如果您的寵物接受的是注射劑型，注射部位可能會出現疼痛或腫脹。
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