丙磺舒
**丙磺舒 (Probenecid)** 是一種磺胺類衍生物，主要作為**促尿酸排泄藥**和**腎小管分泌抑制劑**。 * **獸醫用途**：雖然在小型哺乳動物中的臨床使用有限，但它在**爬行動物醫學**中對治療痛風（高尿酸血症）特別有價值。 * **藥理效用**：在歷史和藥理學上，丙磺舒以其抑制弱有機酸（特別是**β-內醯胺類抗生素**，如青黴素和頭孢菌素）腎臟排泄的能力而聞名。藉此，它能顯著延長這些藥物的半衰期並提高血清濃度。 * **臨床要點**：在狗體內，丙磺舒的消除半衰期（約18小時）比人類（6.5小時）長得多，這在理論上有利於延長昂貴或快速清除藥物的給藥間隔，儘管目前仍缺乏針對狗的充分臨床試驗支持。
作用機制: Probenecid exerts its effects via competitive inhibition at the proximal renal tubules: * **Uricosuric Effect**: Competitively inhibits the **Urate Transporter 1 (URAT1)** on the apical membrane of the proximal tubule → prevents the reabsorption of uric acid from the urine back into the blood → enhances uric acid excretion and lowers serum urate levels. * **Secretion Inhibition**: Competitively inhibits **Organic Anion Transporters (OAT1, OAT3)** on the basolateral membrane → prevents the active tubular secretion of weak organic acids (e.g., penicillins, cephalosporins, NSAIDs) from the blood into the urine → prolongs the systemic half-life of these drugs.
各物種劑量
- Gout · 250 mg PO q12h; can be increased as needed. · PO · q12h · Suggested dosage based upon human data as dose is not established for reptiles.
- Gout · 40 mg/kg PO q12h · PO · q12h
- Gout · 250 mg (total dose) PO twice daily; may increase as needed. · PO · twice daily
劑量為持牌獸醫專業人員的臨床參考。請務必對照最新藥品說明書及個別病患確認。
給藥途徑
禁忌症
- Patients with or susceptible to uric acid renal or bladder calculus formation
- Urate nephropathy (e.g., cancer chemotherapy with rapidly cytolytic agents)
- Severe renal impairment (creatinine clearance < 30 mL/min)
- Gout in birds (can exacerbate the condition)
不良反應
- Headache (humans)
- Inappetence
- Nausea
- Mild vomiting
- Rashes
- Increased rate of gouty attacks initially (if no prophylaxis)
- Hypersensitivity (rare)
- Bone marrow suppression (rare)
- Hepatotoxicity (rare)
- Nephrotic syndrome (rare)
藥物相互作用
- Acyclovir · Increased acyclovir serum concentrations; probenecid can decrease renal excretion
- Antineoplastics (rapidly cytolytic) · Increased chance of uric acid nephropathy
- Aspirin (and other salicylates) · Salicylates antagonize the uricosuric effects of probenecid
- Benzodiazepines (lorazepam, oxazepam) · Probenecid may prolong action or reduce time for onset of action
- Beta-lactam antibiotics · Probenecid may increase serum concentrations by reducing renal excretion
- Beta-lactamase inhibitors (sulbactam, tazobactam) · Probenecid may increase serum concentrations by reducing renal excretion (does not affect clavulanic acid)
- Chlorpropamide · Probenecid decreases elimination; hypoglycemia is possible
- Ciprofloxacin/Enrofloxacin · Probenecid reduces renal tubular secretion of ciprofloxacin by about 50%. Significantly reduces renal excretion of enrofloxacin in goats.
- Dapsone · Possible accumulation of dapsone or its active metabolites
- Furosemide · Increased serum furosemide levels
- Heparin · Probenecid may increase and prolong heparin's effects
- Methotrexate · Probenecid may increase levels; increased risks for toxicity
監測
- Serum uric acid
- Urine uric acid
- Acid-base balance (if concomitant urine alkalinization is used)
過量
Limited information is available in veterinary species. * **Human Data**: One massive (>45 g) overdose caused CNS stimulation, seizures, protracted vomiting, and respiratory failure. * **Management**: Handle initially using standardized protocols for removal of drug from the gut and preventing absorption. Treat supportively. Use caution co-administrating drugs that may compete with probenecid for tubular secretion. Consider contacting an animal poison control center for guidance.
VetSheet 藥物參考供持牌獸醫專業人員作臨床決策輔助之用,不能取代專業判斷或廠方最新藥品說明書。