트리메토프림/설파디아진 및 트리메토프림/설파메톡사졸

강화 설파계 항균제

강화 설파제(흔히 TMS, SMZ-TMP 또는 코트리목사졸로 불림)는 수의학에서 광범위하게 사용되는 광범위 살균성 항균 복합제입니다. **주요 임상 요점:** - **우수한 조직 침투력:** 지용성이 높아 **전립선**, **혈액뇌장벽(CNS)**, **눈**과 같이 침투하기 어려운 조직에서도 치료 농도에 도달할 수 있습니다. - **광범위 스펙트럼:** 메티실린 내성 포도상구균(MRSA/MRSP)의 많은 균주, *노카르디아*, 특정 원충(*톡소플라스마*, *콕시듐*, *폐포자충*)을 포함한 많은 그람 양성 및 음성균에 효과적입니다. - **농에 의한 불활성화:** 약효는 화농성 잔해물과 괴사 조직(PABA와 티미딘이 풍부함)에 의해 크게 억제됩니다. 약효를 발휘하려면 농양을 배농해야 합니다. - **품종 민감성:** 도베르만 핀셔는 설파제 유발 다계통 면역 복합체 질환(과민 반응)에 대한 품종 특이적 감수성이 있는 것으로 알려져 있습니다. - **제형:** 수의용으로 승인된 트리메토프림/설파디아진 제품이 있지만, 많은 수의사들이 인체용으로 승인된 트리메토프림/설파메톡사졸(Bactrim®, Septra®)을 허가 외(off-label)로 사용하여 유사한 효과를 얻고 있습니다.

작용 기전: Potentiated sulfas exhibit **synergistic, bactericidal** activity by sequentially blocking the bacterial folic acid synthesis pathway. Mammalian cells are largely unaffected because they utilize preformed dietary folate rather than synthesizing it. - **Sulfonamides (Bacteriostatic alone):** Act as structural analogues of para-aminobenzoic acid (PABA). They competitively inhibit the bacterial enzyme **dihydropteroate synthase** → blocks the conversion of PABA to dihydrofolic acid (DFA). - **Trimethoprim (Bactericidal alone):** Reversibly inhibits the bacterial enzyme **dihydrofolate reductase** → blocks the conversion of DFA to tetrahydrofolic acid (THFA). - **Synergy:** The sequential blockade completely depletes THFA, an essential cofactor for bacterial DNA and RNA synthesis, leading to rapid bacterial cell death. > *Pharmacologic Note:* The optimal *in vitro* ratio for most susceptible bacteria is 1:20 (trimethoprim:sulfa), but synergistic activity occurs across a wide range (1:1 to 1:40). The serum concentration of the trimethoprim component is generally considered the primary driver of efficacy.

동물 종별 용량

Cats

UTI · 30 mg/kg PO q24h · PO · q24h · 7-14 days
UTI, soft tissue infections · 15 mg/kg PO q12h · PO · q12h · 7-14 days
Susceptible infections · 30 mg/kg q12h · PO · q12h · If treating Nocardia, double dose
Toxoplasmosis · 15 mg/kg PO q12h · PO · q12h · 28 days
Bacterial UTI · 30 mg/kg q12h PO · PO · q12h

Ferrets

Susceptible infections · 30 mg/kg PO twice daily · PO · q12h
Coccidiosis · 30 mg/kg PO once daily · PO · q24h · 14 days

Cattle

Susceptible infections · 44 mg/kg once daily IM or IV using 48% suspension · IM/IV · q24h
Susceptible infections · 25 mg/kg, IV or IM q24h · IV/IM · q24h
Susceptible infections (Calves) · 48 mg/kg IV or IM q24h · IV/IM · q24h

Horses

Respiratory tract infections · 15-30 mg/kg PO q12h · PO · q12h · Give 30 minutes prior to feeding hay

투여 경로

POIVIMSC

금기

Hypersensitivity to sulfonamides, thiazides, or sulfonylurea agents
Severe renal or hepatic impairment
Doberman pinschers (highly susceptible to immune complex disease)
Marked blood dyscrasias
Animals intended for food (in the USA/certain jurisdictions)

이상반응

Dogs: Keratoconjunctivitis sicca (KCS/dry eye - potentially irreversible)
Dogs: Hypersensitivity reactions (Type 1 anaphylaxis or Type 3 serum sickness, polyarthritis, urticaria, facial swelling)
Dogs: Acute neutrophilic hepatitis with icterus, idiosyncratic hepatic necrosis
Dogs: Vomiting, anorexia, diarrhea
Dogs: Hemolytic anemia, agranulocytosis
Dogs: Hypothyroidism (with extended therapy)
Dogs: Crystalluria, hematuria, polyuria, polydipsia
Cats: Anorexia, crystalluria, hematuria, leukopenias, anemias
Horses: Transient pruritus (after IV injection), diarrhea, hypersensitivity, hematologic effects
Injection site reactions: Swelling, pain, tissue damage (IM, SC, or extravasation)

약물 상호작용

Amantadine · May cause toxic delirium (reported in humans)
Antacids · May decrease the bioavailability of sulfonamides if administered concurrently
Cyclosporine · May increase the risk of nephrotoxicity
Digoxin · May increase digoxin levels
Diuretics, Thiazide · May increase risk for thrombocytopenia
Hypoglycemic agents, oral · May potentiate hypoglycemic effects
Methotrexate · May displace from plasma proteins and increase risk for toxic effects; can also interfere with MTX assays
Phenytoin · May increase half-life of phenytoin
Tricyclic antidepressants · May decrease efficacy of the antidepressant
Warfarin · May prolong INR/PT and increase bleeding risk

모니터링

Clinical efficacy
Adverse effects (GI, hypersensitivity)
Complete blood counts (CBC) periodically with chronic therapy
Schirmer Tear Test (STT) in dogs to monitor tear production (e.g., at 5 days, then every 2-3 weeks)
Thyroid function tests (baseline and ongoing) for dogs on long-term treatment

과용량

Manifestations of acute overdosage include GI distress (nausea, vomiting, diarrhea), CNS toxicity (depression, headache, confusion), facial swelling, bone marrow depression, and elevated serum aminotransferases. **Treatment:** - **Oral Overdose:** Empty the stomach following usual protocols and initiate symptomatic/supportive therapy. - **Fluid Therapy:** Maintain hydration. Acidification of urine may increase renal elimination of trimethoprim but increases the risk of sulfonamide crystalluria (especially with sulfadiazine). - **Monitoring:** Monitor complete blood counts and liver parameters. - **Bone Marrow Suppression:** If severe and associated with chronic overdose, may be treated with folinic acid (leucovorin). - *Note:* Peritoneal dialysis is not effective in removing TMP or sulfas from circulation.

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