灰黃黴素
灰黃黴素（Griseofulvin）是一種抑菌性抗黴菌抗生素，在獸醫學中主要用於治療皮膚、毛髮和爪子的**皮癬菌感染**（錢癬）。 **主要臨床重點：** * 它對皮癬菌（如*毛癬菌*、*小孢癬菌*和*表皮癬菌*）具有高度專一性。 * 它對細菌、其他致病真菌或*馬拉色菌*（Malassezia）**沒有療效**。 * **臨床提示：** 由於其潛在的顯著副作用（特別是骨髓抑制和致畸性）以及需要長期治療，灰黃黴素在現代獸醫臨床中正逐漸被更新、更安全的抗黴菌藥物（如**伊曲康唑 (itraconazole)** 和 **特比萘芬 (terbinafine)**）所取代。 * 由於胃腸道吸收的差異，**微粒 (microsize)** 和 **超微粒 (ultramicrosize)** 劑型的劑量有顯著不同。
作用機制: Griseofulvin is a fungistatic agent. It enters susceptible fungal cells and binds to **tubulin**, which disrupts the structure of the **mitotic spindle** → arresting the metaphase of cell division. Additionally, griseofulvin binds to newly synthesized **keratin** in the host. As new skin, hair, and nails grow, the keratin-griseofulvin complex makes these newly formed tissues resistant to fungal invasion, allowing the infected, older tissues to be shed.
各物種劑量
- Susceptible dermatophytic infections · Microsize: 50-120 mg/kg PO; divided daily. Ultramicrosize: 10-15 mg/kg PO twice daily. · PO · divided daily or twice daily · 4-6 weeks or longer · Give with a fatty meal. Treat until culture is negative.
- Susceptible dermatophytic infections · Microsize: 50 mg/kg PO once daily or 25 mg/kg PO q12h for 42-70 days; Ultramicrosize: 5-10 mg/kg PO once daily for 42 days. · PO · once daily or q12h · 42-70 days · Give following a fatty meal or administration of corn oil. Continue for at least 2 weeks after resolution of signs and at least 5 months for onychomycosis.
- Susceptible dermatophytic infections · Microsize: 50 mg/kg PO once daily with fatty meal. · PO · once daily · Prolonged · Used with topical therapy. May double dose in resistant cases. If GI distress occurs may divide dose and give twice daily with food. Begin taking cultures after 4 weeks. Continue therapy for 2 weeks beyond clinical cure and when 2-3 negative cultures are obtained at weekly intervals.
- Feline eosinophilic granuloma complex · Microsize: 25 mg/kg PO twice daily with food. · PO · twice daily · At least one month · Give at least for one month to judge efficacy.
- Susceptible dermatophytic infections · Ultramicrosize: 10-20 mg/kg PO once daily for 1-2 weeks. 100 mg/kg PO given twice (or more) 1 week apart may also be effective. · PO · once daily or weekly · 1-2 weeks · Not FDA-approved for use in food animals and can be very expensive.
- Susceptible dermatophytic infections · 20 mg/kg PO once daily for 6 weeks · PO · once daily · 6 weeks
- Susceptible dermatophytic infections · Using the microsize (not ultra-microsize) products: 5 mg/kg PO once daily. · PO · once daily · Smaller doses (1.25 grams) should be used for foals or ponies. If using ultra-microsize (human) formulations the dose should be reduced by 50%.
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
- Pregnancy (known teratogen)
- Known hypersensitivity to griseofulvin
- Hepatocellular failure
- Horses intended for food
不良反應
- Anorexia
- Vomiting
- Diarrhea
- Anemia
- Neutropenia
- Leukopenia
- Thrombocytopenia
- Depression
- Ataxia
- Hepatotoxicity
- Dermatitis/photosensitivity
- Toxic epidermal necrolysis
- Teratogenesis
藥物相互作用
- Alcohol · Griseofulvin may potentiate the effects of alcohol.
- Aspirin · Griseofulvin may decrease salicylate levels.
- Cyclosporine · Griseofulvin may decrease cyclosporine levels.
- Phenobarbital · May decrease griseofulvin blood concentrations by inducing hepatic microsomal enzymes and/or reducing absorption. Dosage adjustment may be necessary.
- Theophylline · May decrease theophylline half-life and levels in some patients.
- Warfarin · May reduce the anticoagulant activity of coumarin anticoagulants; adjustment may be required.
監測
- Clinical efficacy; fungal culture
- Adverse effects
- CBC; before therapy and q1-3 weeks during therapy
- Liver enzymes (if indicated)
過量
Specifics regarding acute toxicity are limited. Significant overdoses should be managed with gut emptying, activated charcoal, and cathartic administration unless contraindicated. Horses have tolerated 100 mg/kg PO for 20 days without apparent ill effect.
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。