오르비플록사신

항생제 - 플루오로퀴놀론계Critically Important

오르비플록사신은 주로 수의학에서 사용되는 합성 광범위 **플루오로퀴놀론계 항생제**입니다. **농도 의존적 살균 활성**을 보이며, 약물 농도가 최소 억제 농도(MIC) 이하로 떨어진 후에도 세균 증식이 계속 억제되는 유의미한 **항생제 후 효과(PAE)**를 가집니다. 호기성 그람 음성 간균(예: 대장균, 클레브시엘라, 프로테우스, 엔테로박터, 파스퇴렐라) 및 일부 그람 양성 구균(예: 포도상구균)에 매우 효과적입니다. > **임상 요점:** 다른 플루오로퀴놀론계와 마찬가지로 오르비플록사신은 절대 혐기성 세균 및 대부분의 장구균에 대한 효능이 떨어집니다. 책임 있는 항생제 사용을 위해 배양 및 감수성 검사에서 필요성이 확인된 감염에만 제한적으로 사용해야 합니다.

작용 기전: Fluoroquinolones exert their bactericidal effect by targeting two essential bacterial enzymes: * **DNA Gyrase (Topoisomerase II):** The primary target in gram-negative bacteria. It prevents the relaxation of positively supercoiled DNA, which is required for normal transcription and replication. * **Topoisomerase IV:** The primary target in gram-positive bacteria. It interferes with the separation of interlinked replicated DNA molecules. **Mechanism Pathway:** Orbifloxacin binds to the enzyme-DNA complex → inhibits DNA replication and transcription → induces double-stranded DNA breaks → rapid bacterial cell death.

동물 종별 용량

Cats

Susceptible infections · 2.5 mg/kg-7.5 mg/kg · PO · once daily · Tablets. Higher end of the dosing range may be necessary for complicated infections.
Skin infections (wounds and abscesses) · 7.5 mg/kg · PO · once daily · Suspension. For susceptible strains of S. aureus, E. coli, and P. multocida.
Skin and other soft tissue infections · 7.5 mg/kg · PO · q24h · Caution with higher doses due to risk of retinal blindness.

Horses

Susceptible infections · 5 mg/kg · PO · once daily
Susceptible infections · 7.5 mg/kg · PO · once daily

Dogs

Susceptible infections · 2.5 mg/kg-7.5 mg/kg · PO · once daily · Tablets. Higher end of the dosing range may be necessary in hospitalized patients, those with underlying disease, structural alterations, or infections caused by 'problem' pathogens.
Urinary tract infections (cystitis) and skin/soft tissue infections (wounds and abscesses) · 2.5-7.5 mg/kg · PO · once daily · Suspension.
Bacterial cystitis · 2.5 mg/kg · PO · q24h
Skin and other soft tissue infections · 7.5 mg/kg · PO · q24h

투여 경로

POTopical

금기

Immature dogs during the rapid growth phase (2-8 months in small/medium breeds; up to 18 months in large/giant breeds)
Known hypersensitivity to orbifloxacin or other quinolones
Giant-breed dogs <18 months old
Large breeds <12 months old
Small and medium-sized breeds <8 months old
Pregnant or lactating bitches
Animals intended for breeding
Animals <4 months of age (otic preparation)
Animals with a ruptured tympanum (otic preparation)

이상반응

Anorexia
Vomiting
Diarrhea
Arthropathies (cartilage damage) in immature, growing animals
Potential retinal toxicity/blindness in cats (rare, but reported with higher doses of fluoroquinolones)
CNS stimulation (rare)
Cartilage abnormalities in growing animals
CNS adverse effects (potentiated by NSAIDs)
Retinal blindness in cats (dose-dependent)

약물 상호작용

Antacids / Dairy Products · Cations (Mg++, Al+++, Ca++) bind to orbifloxacin and prevent its absorption; separate doses by at least 2 hours.
Other Antibiotics (Aminoglycosides, 3rd-gen cephalosporins, extended-spectrum penicillins) · Unpredictable synergism may occur against some bacteria (particularly Pseudomonas aeruginosa).
Cyclosporine · May exacerbate nephrotoxicity and reduce the metabolism of systemic cyclosporine.
Flunixin · May increase the AUC and elimination half-life of fluoroquinolones.
Glyburide · Severe hypoglycemia is possible.
Iron, Zinc (oral) · Decreased orbifloxacin absorption; separate doses by at least 2 hours.
Methotrexate · Increased methotrexate levels possible, resulting in toxicity.
Nitrofurantoin · May antagonize the antimicrobial activity of fluoroquinolones; concomitant use is not recommended.
Phenytoin · May alter phenytoin levels.
Probenecid · Blocks tubular secretion, potentially increasing blood levels and half-life of orbifloxacin.
Sucralfate · May inhibit absorption of orbifloxacin; separate doses by at least 2 hours. · major
Theophylline · May increase theophylline blood levels. · major

모니터링

Clinical efficacy (resolution of infection)
Gastrointestinal signs (appetite, vomiting, diarrhea)
Vision changes or pupillary dilation in cats
Neurological signs (seizures) in predisposed patients

과용량

In dogs, receiving up to 5X the maximum dose (37.5 mg/kg) for 30 days did not result in any significant adverse effects. In cats, receiving higher dosages exhibited soft feces and decreased body weight gains.

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