硫酸慶大黴素
慶大黴素是一種強效的非腸道給藥**氨基醣苷類抗生素**,主要用於治療嚴重的革蘭氏陰性需氧菌感染。 主要藥理特徵包括: * **抗菌譜**:對革蘭氏陰性需氧菌(如大腸桿菌、克雷伯氏菌、變形桿菌、假單胞菌、沙門氏菌)及部分葡萄球菌具有優異的抗菌活性。對厭氧菌、真菌和病毒無效。 * **濃度依賴型殺菌活性**:其療效取決於達到相對於病原體最低抑菌濃度(MIC)的高血清峰值濃度。 * **抗生素後效應(PAE)**:即使藥物濃度降至MIC以下,細菌生長仍會受到抑制,這支持了現代的**每日一次給藥**方案。 * **毒性特徵**:由於具有顯著的**腎毒性**和**耳毒性**風險,全身性使用通常僅限於其他毒性較低的替代藥物無效的嚴重感染。 > **臨床要點**:毒性風險因素包括原發性腎臟疾病、年齡(新生兒和老年動物)、發燒、敗血症和脫水。貓對前庭(耳毒性)的影響特別敏感。
作用機制: Gentamicin is a **concentration-dependent bactericidal** antibiotic. * **Mechanism**: It actively transports across the bacterial cell membrane via an **oxygen-dependent mechanism** → irreversibly binds to the **30S ribosomal subunit** → causes misreading of mRNA → inhibits bacterial protein synthesis, leading to cell death. * **Environmental Factors**: Antimicrobial activity is significantly enhanced in an **alkaline environment** and inhibited in acidic, purulent, or necrotic environments. * **Resistance**: Because the transport mechanism requires oxygen, **anaerobic bacteria are inherently resistant** to all aminoglycosides.
各物種劑量
- Empiric therapy for susceptible infections · 5-8 mg/kg · IV, SC, IM · q24h · Route not specified in text; assumed IV, SC, IM by Plumb.
- Susceptible infections · 6-8 mg/kg · Not specified · q24h · Neutropenic or immunocompromised patients may need q8h dosing (divided).
- Susceptible infections · 8 mg/kg q24h OR 2-4 mg/kg q8h · IV, IM, SC · q24h or q8h
- Localized, urinary infections · 2.2 mg/kg · IV, IM, SC · q24h · <7 days · Monitor renal function.
- Bacteremia, sepsis · 4.4 mg/kg · IV, IM, SC · q24h · <7 days · Monitor renal function.
- Colibacillosis in neonates · 5 mg · PO, IM · Once · Once · Garacin Pig Pump and Piglet Injection.
- Colibacillosis in weanlings and other swine · 1.1 mg/kg/day in drinking water (concentration of 25 mg/gallon) · PO · Daily · 3 days
- Swine dysentery (Treponema hyodysenteriae) · 2.2 mg/kg/day in drinking water (concentration of 50 mg/gallon) · PO · Daily · 3 days
- Susceptible infections · 5 mg/kg · SC, IM · q24h · Use with caution or avoid use.
- Susceptible infections · 4-8 mg/kg divided and given 2-3 times daily · IM, SC, IV · q8-12h · Use only when culture and sensitivity dictates.
給藥途徑
禁忌症
- Known hypersensitivity to aminoglycosides
- Use with extreme caution in preexisting renal disease
- Use with caution in working dogs (e.g., seeing-eye, herding, hearing-impaired assistance dogs) due to irreversible ototoxicity
- Use with caution in patients with neuromuscular disorders (e.g., myasthenia gravis)
- Do not use in animals with botulism
- Use with caution in rabbits (adversely affects GI flora)
- Use with caution in neonates, geriatrics, and dehydrated patients
- Perforated tympanum (for aural preparations)
- Concurrent use of other nephrotoxic drugs
- Systemic use exceeding 7 days
- Pregnancy
不良反應
- Nephrotoxicity (tubular necrosis)
- Ototoxicity (auditory and vestibular; cats are highly sensitive to vestibular effects)
- Neuromuscular blockade
- Facial edema
- Pain or inflammation at the injection site
- Peripheral neuropathy
- Hypersensitivity reactions
- Rarely: GI signs, hematologic, and hepatic effects
- Nephrotoxicity (acute tubular necrosis)
- Ototoxicity (auditory and vestibular)
- Neuromuscular blockade (rare)
- Delayed epithelial healing of corneal ulcers (ophthalmic use)
- Local irritation
藥物相互作用
- Beta-lactam antibiotics (penicillins, cephalosporins) · Synergistic effects against some bacteria; however, potential for in vitro inactivation of aminoglycosides (do not mix in the same syringe/bag) and in vivo inactivation in patients with renal failure. · major
- Cephalosporins · Potential additive nephrotoxicity (well documented with older cephalosporins like cephalothin).
- Loop or Osmotic Diuretics (e.g., furosemide, torsemide, mannitol) · Concurrent use may increase the nephrotoxic or ototoxic potential of aminoglycosides.
- Other Nephrotoxic Drugs (e.g., cisplatin, amphotericin B, polymyxin B, vancomycin) · Increased risk for nephrotoxicity.
- Neuromuscular blocking agents & General anesthetics · Concomitant use could potentiate neuromuscular blockade.
- Amphotericin B · Increased risk of nephrotoxicity and ototoxicity · major
- Furosemide · Increased risk of nephrotoxicity and ototoxicity · major
- Heparin · In vitro chemical inactivation (do not mix in same syringe) · major
- Non-depolarizing muscle relaxants (Atracurium, Pancuronium, Vecuronium) · Enhanced neuromuscular blockade · major
監測
- Clinical efficacy (resolution of clinical signs, negative cultures)
- Renal toxicity: Baseline and ongoing urinalysis (casts in urine are often the initial sign of impending nephrotoxicity), serum BUN, and creatinine
- Gross monitoring for vestibular (balance) or auditory (hearing) toxicity
- Therapeutic Drug Monitoring (TDM): Serum levels drawn at 1, 2, and 4 hours post-dose. Peak should be >20 mcg/mL; 4-hour trough should be <10 mcg/mL
- Urinalysis (monitor for cellular casts as an early indicator of tubular damage)
- Serum creatinine and BUN
- Hydration status
- Therapeutic Drug Monitoring (TDM): Peak >20 μg/ml, Trough <1 μg/ml
- Auditory and vestibular function
過量
In the event of an inadvertent overdose, three treatments are recommended: 1. **Hemodialysis**: Very effective in reducing serum levels, but rarely a viable option in veterinary medicine. 2. **Peritoneal dialysis**: Reduces serum levels but is much less effective than hemodialysis. 3. **Complexation**: Administration of ticarcillin (12-20 g/day in humans) is reportedly nearly as effective as hemodialysis in complexing and deactivating the drug.
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。