グリセオフルビン
グリセオフルビンは、獣医学において主に皮膚、被毛、爪の**皮膚糸状菌感染症**（白癬）の治療に使用される静真菌性抗生物質です。 **臨床上の重要なポイント：** * 皮膚糸状菌（*Trichophyton*、*Microsporum*、*Epidermophyton*など）に対して高い特異性を持ちます。 * 細菌、その他の病原性真菌、または*マラセチア*酵母には**効果がありません**。 * **臨床のヒント：** 重大な副作用（特に骨髄抑制や催奇形性）の可能性と長期治療が必要なため、現代の獣医療では**イトラコナゾール**や**テルビナフィン**などのより新しく安全な抗真菌薬に置き換えられつつあります。 * 消化管からの吸収率が異なるため、**マイクロサイズ**と**ウルトラマイクロサイズ**の製剤間で投与量が大きく異なります。
作用機序: 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.
動物種別の用量
- 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
投与経路
禁忌
- Pregnancy (known teratogen)
- Known hypersensitivity to griseofulvin
- Hepatocellular failure
- Horses intended for food
有害事象
- Anorexia
- Vomiting
- Diarrhea
- Anemia
- Neutropenia
- Leukopenia
- Thrombocytopenia
- Depression
- Ataxia
- Hepatotoxicity
- Dermatitis/photosensitivity
- Toxic epidermal necrolysis
- Teratogenesis
薬物相互作用
- 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.
モニタリング
- Clinical efficacy; fungal culture
- Adverse effects
- CBC; before therapy and q1-3 weeks during therapy
- Liver enzymes (if indicated)
過量投与
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 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。