氨苄西林
Ampicillin
Ampicillin sodium, Ampicillin trihydrate
別名: Polyflex · Principen · Amfipen · Ampicare · aminobenzylpenicillin · ampicillinum anhydricum · anhydrous ampicillin · AY-6108 · BRL-1341 · NSC-528986 · P-50 · Ampicillin sodium · Aminopenicillin
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)
須由已驗證獸醫確認
- q12h
NA
必須同時考慮的臨床上下文 (3)
- ■ Because penicillins usually have minimal toxicity associated with their use, monitoring for efficacy is usually all that is required unless toxic signs develop. Serum levels and therapeutic drug monitoring are not routinely done with these agents.
- Ampicillin trihydrate (Polyflex®) powder for injection should be stored at or below 25°C (77°F), with excursions permitted up to 30°C (86°F). After reconstitution, it is stable for 3 months when refrigerated.
- Ampicillin sodium powder for injection should be stored at room temperature (15°C-30°C [59°F-86°F]). The drug is relatively unstable after reconstitution and should be used within 1 hour of reconstitution. As the concentration of the drug in solution increases, the stability of the drug decreases. Dextrose may also speed the destruction of the drug by acting as a catalyst in the hydrolysis of ampicillin.
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概覽
氨苄西林 (Ampicillin) 是一種廣效、時間依賴型、具殺菌作用的氨基青黴素類抗生素。
主要藥理特徵包括：
- 抗菌譜： 對許多革蘭氏陽性菌（包含對青黴素敏感的腸球菌如 E. faecium）、厭氧菌（如梭狀芽孢桿菌）及部分革蘭氏陰性需氧菌（E. coli、Klebsiella、Haemophilus、Proteus mirabilis）有效。
- 抗藥性： 與天然青黴素相似，極易被產生β-內醯胺酶的細菌（如金黃色葡萄球菌）破壞而失效。對綠膿桿菌、沙雷氏菌、腸桿菌及非典型病原（黴漿菌、立克次體、黴菌）無效。
- 臨床應用： 由於口服吸收率較差，小動物的口服途徑已大多被阿莫西林 (Amoxicillin) 取代，但注射型氨苄西林仍是重要的基礎療法。
- 鹽類劑型：
- 氨苄西林鈉 (Sodium)： 水溶性高，適合靜脈注射 (IV)，可迅速達到高血清峰值濃度。
- 氨苄西林三水合物 (Trihydrate)： 儲積型長效製劑，供肌肉 (IM) 或皮下 (SC) 注射，吸收較慢且血清峰值較低（約為鈉鹽的一半）。若全身性感染需要較高的最低抑菌濃度 (MIC) 時，不宜使用此劑型。
作用機制
Ampicillin is a beta-lactam antibiotic that exerts its bactericidal effect by interfering with bacterial cell wall synthesis.
- Mechanism: Ampicillin covalently binds to specific Penicillin-Binding Proteins (PBPs) (primarily transpeptidases) located inside the bacterial cell wall.
- Pathway: Binding to PBPs → inhibition of the final transpeptidation step of peptidoglycan cross-linking → weakening of the cell wall structure → activation of endogenous autolytic enzymes (autolysins) → osmotic lysis and bacterial cell death.
- Pharmacodynamics: Efficacy is time-dependent, meaning the free drug concentration must remain above the Minimum Inhibitory Concentration (MIC) for a significant portion of the dosing interval (typically >40-50% of the interval).
安全性與警告
禁忌症
- Patients with a known hypersensitivity to penicillins
- Oral administration in patients with septicemia, shock, or grave illness (due to delayed/diminished GI absorption)
- Oral or parenteral use in small hindgut fermenters (rabbits, guinea pigs, chinchillas, hamsters) due to risk of fatal clostridial enterotoxemia
不良反應
- Gastrointestinal upset (anorexia, vomiting, diarrhea)
- Antibiotic-associated diarrhea and superinfections (alteration of gut flora)
- Hypersensitivity reactions (rashes, fever, eosinophilia, anaphylaxis)
- Neurotoxicity (ataxia, seizures) at very high doses or prolonged use
- Elevated liver enzymes (rare)
- Tachypnea, dyspnea, edema, and tachycardia (reported in dogs)
注意事項
Cross-Reactivity: Use cautiously in patients with documented hypersensitivity to other beta-lactam antibiotics (e.g., cephalosporins, carbapenems), as cross-reactivity can occur.
Species Warning: Severe, potentially fatal enteritis and clostridial enterotoxemia can occur if administered to rabbits, guinea pigs, chinchillas, or hamsters.
Laboratory Interference: May cause false-positive urine glucose determinations when using cupric sulfate solutions (e.g., Clinitest). Glucose oxidase tests are unaffected.
藥物相互作用
Potential in vitro antagonism; clinical significance is debated but concurrent use is traditionally discouraged.
Ampicillin may decrease the renal excretion of methotrexate, leading to increased levels and potential toxicity.
Competitively blocks the tubular secretion of penicillins, increasing serum levels and prolonging half-life.
In vitro inactivation of aminoglycosides if mixed in the same syringe or fluid bag. May also occur in vivo in patients with severe renal failure.
Antagonism of bactericidal effect due to bacteriostatic action
Antagonism of bactericidal effect due to bacteriostatic action
Antagonism of bactericidal effect due to bacteriostatic action
In vitro inactivation if mixed in the same syringe; however, exhibits synergistic antimicrobial effects when used concurrently in vivo
監測
- Clinical efficacy (resolution of infection signs)
- Adverse effects (GI signs, hypersensitivity reactions)
- Therapeutic drug monitoring is not routinely required due to the wide therapeutic index
藥物動力學
半衰期
吸收
Relatively stable in gastric acid. Oral absorption is 30-55% in monogastric animals on an empty stomach; food decreases the rate and extent of absorption. Parenteral trihydrate salt achieves serum levels approximately 1/2 those of a comparable dose of the sodium salt.
分佈
Widely distributed to many tissues (liver, lungs, muscle, bile, ascitic/pleural/synovial fluids). Volume of distribution is ~0.3 L/kg in dogs, 0.167 L/kg in cats, and 0.16-0.5 L/kg in cattle. Crosses inflamed meninges (10-60% of serum levels). Low levels in aqueous humor, tears, sweat, saliva, and milk. Crosses the placenta. Approximately 20% bound to plasma proteins.
代謝
Some of the drug is metabolized by hydrolysis to inactive penicilloic acids.
排除
Eliminated primarily through renal mechanisms, principally by tubular secretion. Excreted in the urine.
過量
Acute oral penicillin overdoses are unlikely to cause significant problems other than gastrointestinal distress (vomiting, diarrhea, anorexia).
In humans, very high dosages of parenteral penicillins, particularly in patients with underlying renal disease, have induced CNS effects (e.g., seizures, ataxia). Treatment is generally supportive and symptomatic.
可用產品
劑型
- Powder for injection (Ampicillin sodium)
- Powder for injection suspension (Ampicillin trihydrate)
- Oral capsules
- Powder for oral suspension
獸醫用
- Ampicillin Trihydrate Injection Powder for Suspension: 10 g and 25 g vials (Polyflex)
人用標示
- Ampicillin Sodium Powder for Injection: 250 mg, 500 mg, 1 g, 2 g vials
- Ampicillin Oral Capsules (as trihydrate): 250 mg, 500 mg (Principen)
- Ampicillin Powder for Oral Suspension (as trihydrate): 125 mg/5 mL, 250 mg/5 mL (Principen)
各地核准狀態
POM-V classification
POM-V (Prescription Only Medicine - Veterinarian)
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儲存與穩定性
Capsules and powder for oral suspension: Store at room temperature (15-30°C). Reconstituted oral suspension: Stable for 14 days refrigerated (2-8°C) or 7 days at room temperature. Ampicillin trihydrate for injection (Polyflex): Stable for 3 months refrigerated. Ampicillin sodium for injection: Relatively unstable after reconstitution; generally use within 1 hour. Stability decreases as concentration increases. Dextrose speeds destruction. At ≤30 mg/mL in sterile water or 0.9% NaCl, stable up to 48 hours at 4°C.
飼主須知
- 給藥方式： 除非獸醫師另有指示，否則此藥物應在空腹時口服（飯前至少1小時或飯後2小時），以確保最佳吸收效果。
- 保存方法： 口服懸浮液請保存在冰箱中，並在14天後丟棄任何未用完的藥水。若存放在室溫下，請於7天後丟棄。
- 副作用： 可能會出現輕微的腸胃不適（嘔吐、腹瀉或食慾下降）。如果這些症狀很嚴重或持續存在，請聯繫您的獸醫師。
- 過敏反應： 請留意過敏反應的跡象，例如臉部腫脹、蕁麻疹、皮疹或呼吸困難。如果出現這些情況，請立即尋求獸醫協助。
- 完成療程： 即使您的寵物看起來已經好轉，也請務必按照指示完成整個處方療程，以防止產生抗藥性細菌。
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