特比萘芬
特比萘芬（Terbinafine）是一種合成的**丙烯胺類（allylamine）抗黴菌**藥物，提供口服與外用劑型。 **主要臨床特徵：** * **主要用途：** 對犬貓的皮癬菌感染（如小孢癬菌、毛癬菌）非常有效。也可用於治療全身性黴菌感染（如麴菌症），特別是在鳥類中。 * **良好的藥物交互作用安全性：** 與唑類（azole）抗黴菌藥（如酮康唑、伊曲康唑）不同，特比萘芬的主要作用機制不依賴細胞色素 P-450 酵素系統，因此藥物交互作用明顯較少，且不會抑制哺乳動物的睪固酮或皮質醇合成。 * **藥理學特點：** 特比萘芬具有高度脂溶性與**嗜角質性（keratinophilic）**。它會廣泛分佈於皮膚、皮脂和毛囊中，即使在停藥後，仍能在這些組織中維持數週的治療濃度（這使得脈衝式療法成為可能）。 * **耐受性：** 在獸醫病患中通常具有良好的耐受性，最常見的副作用為輕微的腸胃道不適（嘔吐）。
作用機制: Terbinafine exerts its antifungal activity by interfering with fungal sterol biosynthesis at an early stage. * It selectively and reversibly inhibits the fungal enzyme **squalene monooxygenase** (also known as squalene 2,3-epoxidase). * This blockade prevents the conversion of squalene to lanosterol → leading to a profound deficiency of **ergosterol** (a critical component of the fungal cell membrane). * Simultaneously, the inhibition causes an intracellular **accumulation of squalene**, which is directly toxic to the fungal cell, leading to rapid cell death. This dual mechanism makes terbinafine primarily **fungicidal** against dermatophytes, though it may only be **fungistatic** against certain yeasts like *Candida spp.*
各物種劑量
- Dermatophytic infections (Pulse therapy) · 20 mg/kg · PO · q24h · 7 days on, then 21 days off · Maintained terbinafine concentrations in hair above therapeutic levels. Higher doses (40 mg/kg) or continuous administration caused emesis and elevated hepatic enzymes.
- Dermatophytic infections · 10-20 mg/kg · PO · q24h · Appears to be better tolerated than either ketoconazole or itraconazole.
- Dermatophytic infections (when other drugs are not tolerated) · 25 mg/kg · PO · q24h
- Dermatophyte (M. canis) mycetomas · 26-31 mg/kg · PO · q24h · 12-14 weeks · Achieved clinical and mycological cure in a case report of two cats.
- Cryptococcal infections (azole-resistant) · 10 mg/kg · PO · q24h · Life-long · Can rectify clinical signs, though cats with CNS cryptococcus usually require treatment for life.
- Antifungal (Systemic/Dermatophytosis) · 20-40 mg/kg · PO · q24h · Not specified
- Localized Malassezia infections · Apply a thin layer · topical · Not specified · Not specified · Use 1% cream.
- Avian mycotic infections (Aspergillus) · 10-15 mg/kg · PO · q12-24h · Appears to be well tolerated by a number of avian species.
- Avian mycotic infections (Aspergillus) · 1 mg/mL aqueous solution · Nebulization · Not specified
給藥途徑
禁忌症
- Known hypersensitivity to terbinafine
- Active or chronic liver disease
- Significantly impaired renal function
- Perforated eardrum (for ear gel administration)
- Generalized demodicosis (topical or systemic use)
- Pregnant animals
- Breeding animals
不良反應
- Vomiting
- Inappetence
- Diarrhea
- Lethargy (reported in cats)
- Hepatotoxicity / Liver failure (very rare, reported in humans)
- Neutropenia (very rare, reported in humans)
- Serious skin reactions like Toxic Epidermal Necrolysis or Stevens-Johnson syndrome (very rare, reported in humans)
- Diarrhoea
- Increased liver enzymes
- Pruritus (cats)
- Topical irritation (due to alcohol content in topical solutions)
- Transient deafness or impaired hearing (in elderly dogs after administration of ear gel)
藥物相互作用
- Cyclosporine · Terbinafine may increase the elimination and decrease the efficacy of cyclosporine.
- Rifampin · May increase terbinafine clearance, potentially requiring higher terbinafine doses. · moderate
- Beta-blockers · Terbinafine shares the CYP2D6 metabolic pathway and could theoretically alter the metabolism of beta-blockers.
- MAO Inhibitors (e.g., amitraz, selegiline) · Terbinafine shares the CYP2D6 metabolic pathway and could theoretically alter the metabolism of MAOIs.
- SSRIs (e.g., fluoxetine) · Terbinafine shares the CYP2D6 metabolic pathway and could theoretically alter the metabolism of SSRIs.
- Tricyclic Antidepressants · Terbinafine shares the CYP2D6 metabolic pathway and could theoretically alter the metabolism of TCAs.
- Cimetidine · May decrease the clearance of terbinafine, potentially increasing plasma concentrations (Clinical Pearl) · moderate
監測
- Clinical efficacy (resolution of fungal lesions)
- Baseline liver enzymes prior to therapy
- Periodic liver enzyme monitoring as needed, especially during long-term treatment
- CBC (baseline and periodic)
- Liver function tests (ALT, AST, Bilirubin)
- Renal function tests
- Clinical response (skin scrapings, fungal cultures)
過量
There is limited information regarding acute toxicity in veterinary species. In humans, acute ingestions of up to 5 grams have been reported without serious adverse effects. Treatment of massive overdose should be supportive and symptomatic.
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