リンコマイシン
**リンコマイシン**は、クリンダマイシンに密接に関連する狭〜中域スペクトルの**リンコサミド系抗生物質**です。獣医学においては、主に感受性のあるグラム陽性好気性球菌（ブドウ球菌やレンサ球菌など）、様々な嫌気性菌、およびマイコプラズマによる感染症の治療に使用されます。 主な薬理学的特徴： - **抗菌スペクトル**: 多くの嫌気性菌、グラム陽性好気性菌、トキソプラズマに有効です。一般にグラム陰性好気性菌やエンテロコッカス・フェカリスには無効です。 - **臨床的有用性**: 犬、猫、豚での使用がFDAに承認されていますが、小動物では経口吸収性が良く、抗菌活性が高く、毒性が低いクリンダマイシンに取って代わられつつあります。 - **毒性の特徴**: 後腸発酵動物や反芻動物（馬、ウサギ、げっ歯類など）には**絶対禁忌**です。重篤で致命的なクロストリジウム性腸炎を引き起こすリスクがあるためです。 > **臨床のポイント**: リンコマイシンは時間依存性の抗生物質です。投与間隔中、薬物濃度を最小発育阻止濃度（MIC）以上に維持することが臨床的成功に不可欠です。
作用機序: Lincomycin exerts its antibacterial effects by binding to the **50S ribosomal subunit** of susceptible bacteria. **Mechanism Pathway**: Drug enters bacterial cell → Binds reversibly to the **50S ribosomal subunit** → Blocks the transpeptidation and translocation steps → **Inhibits bacterial protein synthesis**. Depending on the concentration of the drug at the infection site and the specific susceptibility of the targeted organism, lincomycin can be either **bacteriostatic** or **bactericidal**. > **Note**: Complete cross-resistance occurs between lincomycin and clindamycin, and partial cross-resistance occurs with macrolides like erythromycin due to overlapping ribosomal binding sites.
動物種別の用量
- Skin and soft tissue infections · 11 mg/kg IM q12h or 22 mg/kg IM q24h · IM · q12h or q24h · 12 days or less
- Systemic infections · 15 mg/kg PO q8h or 22 mg/kg PO q12h · PO · q8h or q12h · 12 days or less
- Susceptible bacterial infections · 22 mg/kg · IM · q24h
- Susceptible bacterial infections · 11 mg/kg · IM · q12h
- Susceptible bacterial infections · 11-22 mg/kg · IV · q12-24h · Must be administered slowly
- Susceptible bacterial infections · 22 mg/kg · PO · q12h
- Susceptible bacterial infections · 15 mg/kg · PO · q8h
- Mycoplasmal (M. hyopneumoniae) pneumonia · Fed at 200 grams per ton of feed for 21 days or 11 mg/kg IM once daily · PO, IM · Continuous in feed or once daily IM · 21 days (feed)
- Susceptible infections · 11 mg/kg IM once daily for 3-7 days; or added to drinking water at a rate of 250 mg/gallon (average of 8.36 mg/kg/day) · IM, PO · Once daily (IM) or continuous in water · 3-7 days (IM)
- Susceptible infections · 10-15 mg/kg PO three times daily; 10 mg/kg IM twice daily · PO, IM · Three times daily (PO) or twice daily (IM)
投与経路
禁忌
- Rabbits
- Hamsters
- Guinea pigs
- Horses
- Ruminants (cattle, sheep, goats)
- Patients with known hypersensitivity to lincosamides
- Patients with preexisting monilial (yeast) infections
- Neonatal animals (relative contraindication due to gut flora effects)
- Rapid intravenous administration
- Known hypersensitivity to lincosamides
- Use with caution in patients with severe liver disease
有害事象
- Gastroenteritis (emesis, loose stools, bloody diarrhea in dogs)
- Pain and inflammation at IM injection sites
- Hypotension and cardiopulmonary arrest (if administered rapidly IV)
- Gastrointestinal disturbances in swine
- Diarrhea in nursing neonates (drug distributes into milk)
- Diarrhoea (potentially haemorrhagic)
- Colitis
- Hepatotoxicity (in patients with pre-existing liver disease)
- Cardiac depression (if given rapidly IV)
- Peripheral neuromuscular blockade (if given rapidly IV)
薬物相互作用
- Cyclosporine · Lincomycin may reduce systemic levels of cyclosporine.
- Erythromycin · In vitro antagonism occurs due to competing ribosomal binding sites; concomitant use should be avoided.
- Kaolin · Reduces the absorption of oral lincomycin by up to 90%. If both are necessary, separate doses by at least 2 hours. · moderate
- Neuromuscular blocking agents (e.g., pancuronium) · Lincomycin possesses intrinsic neuromuscular blocking activity and may enhance the effects of these agents; use cautiously.
- Neuromuscular blocking agents · Enhanced neuromuscular blockade action · major
- Chloramphenicol · Antagonistic antimicrobial action (competes for 50S ribosomal binding site) · major
- Macrolides · Antagonistic antimicrobial action (competes for 50S ribosomal binding site) · major
モニタリング
- Clinical efficacy (resolution of infection)
- Adverse effects, particularly severe or bloody diarrhea
- Liver function tests (AST, ALT, Alk. Phosph.) may show slight, usually clinically insignificant, increases
- Fecal consistency (monitor for diarrhoea or haemorrhagic stool)
- Liver enzymes (in patients with pre-existing hepatic impairment)
過量投与
There is limited information regarding acute overdoses. Lincomycin appears to have a wide margin of safety in dogs. Oral doses up to 300 mg/kg/day for up to one year, or parenteral doses of 60 mg/kg/day, did not result in apparent toxicity. If a massive overdose occurs, standard supportive care and gastrointestinal decontamination (if oral and recent) should be considered.
VetSheet の薬剤リファレンスは、獣医療従事者向けの臨床意思決定支援を目的としており、専門的判断やメーカーの最新添付文書に代わるものではありません。