セフォベシン
**セフォベシン (Cefovecin)** は、犬および猫用に承認された長時間作用型の注射用第3世代セファロスポリン系抗生物質です。 **主な臨床的特徴：** * **コンプライアンスの向上：** 飼い主が経口投与を続けるのが困難な場合や、経口抗生物質の忍容性や吸収が悪い患者にとって最大のメリットとなります。 * **抗菌スペクトル：** 第3世代セファロスポリンとして広域スペクトルを持ちます。*Staphylococcus pseudintermedius*、*Streptococcus canis* (Group G)、*Pasteurella multocida* などの一般的な皮膚病原菌に対して高い有効性を示します。 * **制限事項：** 緑膿菌 (*Pseudomonas* spp.) や腸球菌には**無効**です。また、タンパク結合率が非常に高いため、標準的な承認用量では全身性（尿路以外）の大腸菌感染症を治療するための有効な血清中濃度に達しません。 * **薬物動態学的特徴：** 血漿タンパク質への高い親和性とゆっくりとした解離により半減期が非常に長く、1回の注射で標的病原菌の最小発育阻止濃度 (MIC) に応じて数日から数週間にわたり治療的な抗菌濃度を維持します。
作用機序: Cefovecin is a **time-dependent, bactericidal** beta-lactam antibiotic. * **Mechanism:** Like other cephalosporins, cefovecin mimics the D-alanyl-D-alanine terminal of the peptidoglycan chain. It binds to and irreversibly inhibits bacterial **Penicillin-Binding Proteins (PBPs)**, specifically **transpeptidases** and **carboxypeptidases**. * **Pathway:** Inhibition of PBPs → Prevents cross-linking of peptidoglycan chains → Weakens the bacterial cell wall → Osmotic instability → **Bacterial cell lysis and death**. * **Efficacy:** Because it is a time-dependent antibiotic, maintaining free (unbound) drug concentrations above the Minimum Inhibitory Concentration (MIC) of the target pathogen for a significant portion of the dosing interval is critical for its bactericidal efficacy.
動物種別の用量
- Skin infections due to S. intermedius or S. canis (Group G) (USA Label) · 8 mg/kg SC once. A second injection (same dose/route) may be administered if response to therapy is not complete 7 days later (for S. intermedius infections) and 14 days later for S. canis (Group G) infections. Maximum treatment should not exceed 2 injections. · SC · once (may repeat in 7-14 days) · Maximum 2 injections
- Skin and soft tissue infections (UK Label) · 8 mg/kg SC once. If required, treatment may be repeated at 14 day intervals up to a further three times. · SC · once (may repeat q14d) · Up to 4 injections total · Treatment of pyoderma should be extended beyond complete resolution of clinical signs.
- Severe infections of the gingival and periodontal tissues (UK Label) · 8 mg/kg SC once. · SC · once · Single dose · Used as adjunctive treatment to mechanical or surgical periodontal therapy.
- Urinary Tract Infections (UK Label) · 8 mg/kg SC once. · SC · once · Single dose
- Skin, soft tissue, urinary tract infections, and severe periodontal disease · 8 mg/kg · SC · every 14 days · up to 3 times · Equivalent to 1 ml/10 kg of reconstituted drug.
- Skin infections (wounds and abscesses) caused by susceptible strains of Pasteurella multocida (USA Label) · 8 mg/kg SC as a single, one-time subcutaneous injection. · SC · once · Single dose · Therapeutic concentrations are maintained for approximately 7 days for P. multocida infections.
- Skin and soft tissue abscesses and wounds (UK Label) · 8 mg/kg SC once. If required, an additional dose may be administered 14 days after the first injection. · SC · once (may repeat in 14 days) · Up to 2 injections
投与経路
禁忌
- Known allergy or hypersensitivity to cefovecin, other cephalosporins, or penicillins (beta-lactams)
- Small herbivores (e.g., guinea pigs, rabbits) due to risk of fatal dysbiosis
- Dogs or cats less than 4 months of age (USA label) or less than 8 weeks of age (UK label)
有害事象
- Lethargy and depression
- Anorexia
- Vomiting
- Mild to moderate increases in liver enzymes (ALT, GGT)
- Increases in BUN and moderately elevated serum creatinine (observed in cats)
- Injection site irritation, vocalization, and transient edema
- Hypersensitivity reactions and anaphylaxis (rare but potentially fatal)
- Myelotoxicity creating toxic neutropenia (rare class effect)
- Anemia, thrombocytopenia, and prolonged coagulation times (rare class effect)
薬物相互作用
- Carprofen · May compete for plasma protein binding sites, potentially increasing the free (active) concentrations of either drug.
- Furosemide · May compete for plasma protein binding sites. · moderate
- Doxycycline · May compete for plasma protein binding sites.
- Ketoconazole · May compete for plasma protein binding sites.
- NSAIDs, Propofol, Cardiac, Anticonvulsant, and Behavioral medications · Concurrent use of highly protein-bound drugs may compete with cefovecin binding and cause adverse reactions, though actual clinical significance is not fully established.
- NSAIDs · Competition for plasma protein binding, potentially altering free drug concentrations · moderate
モニタリング
- Clinical efficacy (resolution of clinical signs of infection)
- Adverse effects (e.g., gastrointestinal upset, lethargy, injection site reactions)
- Renal and hepatic parameters in patients with pre-existing organ dysfunction
過量投与
Acute overdoses are generally well tolerated and relatively safe. * **Dogs:** Administered SC up to 180 mg/kg (22.5X the labeled dose) showed only injection site irritation, vocalization, and transient edema (which resolved within 8-24 hours). * **Cats:** Administered the same 22.5X dose showed similar injection site signs. However, 10 days post-injection, treated cats had lower mean white blood cell counts compared to controls, and one cat exhibited a small amount of bilirubinuria on day 10. * **Treatment:** If massive overdose occurs or severe adverse effects are noted, treatment is symptomatic and supportive. Due to the long half-life, prolonged monitoring may be required.
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