サラゾスルファピリジン / スルファサラジン
スルファサラジンは、サルファ系抗菌薬（**スルファピリジン**）とサリチル酸系抗炎症薬（**メサラジン**または**5-ASA**）がアゾ結合したユニークな局所作用型プロドラッグです。 - **主な用途**: 犬および猫の**特発性炎症性腸疾患 (IBD)**、特に**形質細胞・リンパ球性大腸炎**（大腸性下痢）の基本的な治療薬です。犬の血管炎の補助治療としても使用されます。 - **制限事項**: 活性化に結腸の細菌を必要とするため、小腸の疾患には効果がありません。 - **臨床上のポイント**: 大腸炎には非常に有効ですが、犬では**乾性角結膜炎 (KCS)**（ドライアイ）のリスクがあるため、獣医療での使用には慎重なモニタリングが必要です。早期に発見されない場合、不可逆的な損傷につながる可能性があります。猫はサリチル酸塩に対して本来敏感であるため、慎重な投与が必要です。
作用機序: Sulfasalazine acts as a targeted delivery vehicle to transport anti-inflammatory medication directly to the colon. - **Delivery**: The intact drug passes mostly unabsorbed (only 10-33% absorbed) through the stomach and small intestine. - **Activation**: In the colon, **bacterial azoreductase enzymes** cleave the diazo bond. - **Mechanism**: - **5-Aminosalicylic Acid (5-ASA / Mesalamine)** → Acts locally on the colonic mucosa to inhibit **cyclooxygenase (COX)** and **lipoxygenase (LOX)** pathways → Decreases production of pro-inflammatory **prostaglandins** and **leukotrienes**. It also acts as a local free radical scavenger. - **Sulfapyridine** → Provides local antibacterial effects, though it is rapidly absorbed systemically and is responsible for the majority of the drug's adverse effects (e.g., KCS, hepatotoxicity).
動物種別の用量
- Inflammatory large bowel disease · 10-20 mg/kg PO once daily. · PO · q24h · Unspecified · Use cautiously in cats because of their sensitivity to salicylates.
- Inflammatory large bowel disease · 10-20 mg/kg PO q24 hours (once daily) tapered to the lowest effective dose · PO · q24h · Unspecified
- Inflammatory large bowel disease · 10-20 mg/kg PO q8-12h (maximum of 10 days) · PO · q8-12h · Maximum 10 days
- Inflammatory large bowel disease · 10-20 mg/kg PO q8-24h; up to a maximum of 10 days treatment · PO · q8-24h · Maximum 10 days
- All uses (Management of colitis) · 10-20 mg/kg · PO · q8-12h
- General · 10-20 mg/kg PO 2-3 times a day · PO · q8-12h · Unspecified
- General · 25 mg (total dose) PO twice daily · PO · q12h · Unspecified
- Inflammatory large bowel disease · 20-40 mg/kg PO q8h for 3 weeks, followed by 20-40 mg/kg q12h for 3 weeks, and 10-20 mg/kg q12h for 3 weeks. · PO · q8h then q12h · 9 weeks
- Inflammatory large bowel disease · 20-48.4 mg/kg (maximum total dose of one gram in refractory patients) PO q8h. · PO · q8h · Minimum 4 weeks · May consider an initial dose of 12.5 mg/kg, q8h. After signs resolve, reduce dosage by 25% at 2 week intervals.
投与経路
禁忌
- Hypersensitivity to sulfasalazine, sulfonamides, or salicylates
- Intestinal or urinary obstructions
- Doberman pinschers (highly susceptible to sulfonamide-induced polysystemic immune complex disease)
- Dobermanns (appear to be highly sensitive to adverse effects associated with sulfapyridine)
- Patients with known hypersensitivity to sulfonamides or salicylates
有害事象
- Keratoconjunctivitis sicca (KCS) in dogs
- Anorexia
- Vomiting
- Cholestatic jaundice
- Hemolytic anemia
- Leukopenia
- Decreased sperm counts
- Allergic dermatitis
- Keratoconjunctivitis sicca (KCS)
薬物相互作用
- Chlorpropamide · Hypoglycemic effects could be potentiated
- Digoxin · Sulfasalazine may reduce absorption of digoxin · moderate
- Ferrous sulfate (or other iron salts) · May decrease the blood levels of sulfasalazine if administered concurrently
- Folic acid · Oral absorption of folic acid may be inhibited
- Warfarin · Potentially sulfasalazine could potentiate warfarin
- Folate · Measurement of serum folate concentration may be affected · minor
- Thyroxine · May cause a reduction in serum thyroxine concentrations · minor
モニタリング
- Clinical efficacy (resolution of diarrhea/colitis signs)
- Schirmer tear tests (STT) prior to therapy and on rechecks (especially in middle-aged to older dogs) to monitor for KCS
- Complete Blood Count (CBC) occasionally with chronic therapy
- Liver function tests occasionally with chronic therapy
- Schirmer tear test (STT) periodically
- Clinical signs of KCS (ocular discharge, blepharospasm)
- Liver enzymes (due to risk of cholestatic jaundice)
- Thyroid panel (if on long-term therapy)
過量投与
Massive overdoses could cause significant **salicylate and/or sulfonamide toxicity**. - **Treatment**: Standard protocols for decontamination (empty stomach, cathartics, etc.) should be considered. - **Supportive Care**: Urine alkalinization and forced diuresis may be beneficial in selected cases to enhance elimination.
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。