スルファクロルピリダジンナトリウム
スルファクロルピリダジンナトリウムは、短〜中時間作用型で低脂溶性のスルホンアミド系抗菌薬です。獣医療では主に、生後1ヶ月未満の子牛や豚の**大腸菌**（E. coli）による腸管感染症の治療に適応されます。また、成牛やその他の動物種において、一般的なスルホンアミド系薬剤として注射で用いられることもあります。 **臨床のポイント:** * **時間依存性・静菌性**の抗生物質であるため、一定の投与間隔を維持することが有効性のために重要です。 * スルホンアミド系に対する耐性菌は広く増加していますが、特定の群管理においては依然として有用な薬剤です。 * 通常の生理的なpHの尿中では高い溶解性を示しますが、脱水状態や尿が高度に濃縮・酸性化している患者では、結晶尿のリスクが残ります。
作用機序: Sulfonamides are generally bacteriostatic agents. They act as structural analogues of para-aminobenzoic acid (PABA). * They competitively inhibit the bacterial enzyme **dihydropteroate synthase**. * This blocks the incorporation of PABA into **dihydropteroic acid** → preventing the biosynthesis of **tetrahydrofolic acid** (the active form of folic acid). * Because mammalian cells utilize preformed dietary folic acid and do not synthesize their own, they are generally unaffected by this mechanism. * Efficacy is significantly reduced in the presence of pus, necrotic tissue, or extensive cellular debris, as these environments are rich in PABA which outcompetes the drug.
動物種別の用量
- Diarrhea caused or complicated by E. coli in calves less than one month of age · 33-49.5 mg/kg PO, or IV twice daily · PO/IV · q12h · 1-5 days · Suggest initiating therapy with intravenous preparation and then changing to oral if possible
- Enteric bacterial infections (E. coli) · Mix 1/4 teaspoonful per liter of water and use as only supply of drinking water · PO · continuous · 5-10 days · Using the oral powder. May be effective for many E. coli enteric infections.
- Enteric bacterial infections (E. coli) · Mix 3/4 teaspoonsful per 2 quarts of water · PO · continuous · Using the oral powder. Fairly effective for enteric infections, particularly E. coli. Reserved for clients who are unable to give other medications by mouth or parenterally.
- E. coli and coccidiosis in pigeons · 1200 mg per gallon of drinking water · PO · continuous · Very effective for E. coli and it is a good coccidiostat.
- Colibacillosis · 44-77 mg/kg PO per day (divide dose and give twice daily if treating individual animals) · PO · q12h or q24h · 1-5 days
用量は獣医療従事者向けの臨床リファレンスです。必ず最新の添付文書と個々の患者で確認してください。
投与経路
禁忌
- Hypersensitivity to sulfonamides, thiazides, or sulfonylurea agents
- Severe renal impairment
- Severe hepatic impairment
有害事象
- Crystalluria
- Hematuria
- Renal tubule obstruction
- Keratoconjunctivitis sicca (KCS) in dogs
- Bone marrow depression
- Hypersensitivity reactions (rashes, dermatitis)
- Focal retinitis
- Fever
- Vomiting
- Nonseptic polyarthritis
- Muscle weakness, blindness, ataxia, and collapse (with rapid IV injection)
- Tissue irritation and necrosis (with IM or SC injection)
- Temporary depression of normal cellulytic function in the ruminoreticulum
薬物相互作用
- Antacids · May decrease the oral bioavailability of sulfonamides if administered concurrently
モニタリング
- Clinical efficacy (resolution of diarrhea/infection)
- Adverse effects
- Hydration status and urine output
過量投与
Acute toxicity secondary to overdoses apparently occurs only rarely in veterinary species. * **Signs of Toxicity:** In addition to standard adverse effects, **CNS stimulation** and **myelin degeneration** have been noted after very high dosages. * **Treatment:** Treatment is largely supportive and symptomatic. Ensure aggressive fluid therapy to maintain urine output and prevent crystalluria.
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。