イトラコナゾール
Itraconazole
別名: Sporanox · Intrafungol · Itrafungol · itraconazolum · oriconazole · R-51211
VetSheet 獣医チームが監修更新日 2026年5月15日エビデンスに基づく獣医学リファレンス
用量は獣医専門家向けの臨床参考資料です。必ず最新の医薬品情報および個別症例に基づいて確認してください。
動物種別用量
🌎 NA — North America🌍 EU — Europe
犬
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Malassezia dermatitis | 5 mg/kg PO once daily | PO | q24h | 3 weeks | 🌎 NA |
| Pulse therapy for Malassezia dermatitis | 5 mg/kg for 2 consecutive days per week | PO | 2 consecutive days per week | 3 weeks | 🌎 NA |
| Dermatophytosis | 5 mg/kg PO once daily | PO | q24h | Prolonged course required | 🌎 NA |
| Dermatophytosis (Pulse therapy) | 5 mg/kg PO once daily on an every other week schedule | PO | q24h (pulse) | Three 'pulses' of one week on, one week off | 🌎 NA |
| Blastomycosis | 5 mg/kg PO once daily | PO | q24h | At least 30 days after all signs resolve (total 60-90 days) | 🌎 NA |
| Histoplasmosis | 10 mg/kg daily PO | PO | q24h | At least 30 days after all signs resolve (total at least 90 days) | 🌎 NA |
| Blastomycosis (Alternative) | 5 mg/kg PO once a day or divided twice a day | PO | q24h or q12h | 2-3 months or until active disease is not apparent | 🌎 NA |
| Coccidiomycosis | 5-10 mg/kg PO once daily | PO | q24h | 6-12 months | 🌎 NA |
| Sporotrichosis | 5-10 mg/kg once daily | PO | q24h | 30 days beyond complete resolution of detectable lesions | 🌎 NA |
| Pythiosis or lagendiosis (after lesion resection) | 10 mg/kg PO once daily | PO | q24h | At least 2 months after surgery | 🌎 NA |
| Zygomycosis | 5-10 mg/kg PO q24h | PO | q24h | 3-6 months for non-resectable lesions | 🌎 NA |
| Idiopathic lymphoplasmacytic (chronic) rhinitis (LPR) | 5 mg/kg PO q12h | PO | q12h | Minimum of 3-6 months | 🌎 NA |
| Nasal aspergillosis | 5 mg/kg PO q12h | PO | q12h | 3-6 months | 🌎 NA |
| Coccidioidomycosis | 5-10 mg/kg PO q24h or 5 mg/kg PO q12h | PO | q24h or q12h | — | 🌎 NA |
| General use (fungal infections) | 5 mg/kg | PO | q24h | 4-20 weeks of treatment may be needed, dependent upon culture results | 🌍 EU |
- Malassezia dermatitis: Fair evidence supports recommendation
- Dermatophytosis: 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.
- Dermatophytosis (Pulse therapy): Toxicity problems are rare with this protocol.
- Blastomycosis: Give with food.
- Histoplasmosis: Give with food. If intestinal histoplasmosis, treat with amphotericin B initially.
- Blastomycosis (Alternative): A loading dose of 10 mg/kg once a day (or divided twice a day) for the first three days may reduce the 'lag' phase.
- Pythiosis or lagendiosis (after lesion resection): Given with terbinafine at 5-10 mg/kg PO q24h.
- Zygomycosis: After aggressive surgical resection or for non-resectable lesions.
- Idiopathic lymphoplasmacytic (chronic) rhinitis (LPR): Has shown dramatic beneficial improvement in some dogs.
- Nasal aspergillosis: May cure up to 60-70% of dogs, although some studies show marginal efficacy.
猫
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Histoplasmosis | 10 mg/kg daily PO | PO | q24h | At least 2-4 months | 🌎 NA |
| Cryptococcosis | 50-100 mg per cat per day PO | PO | q24h | Many months (mean 8.5 months) | 🌎 NA |
| Blastomycosis | 10 mg/kg PO once a day or divided twice a day | PO | q24h or q12h | 2-3 months or until active disease is not apparent | 🌎 NA |
| Coccidiomycosis | 5-10 mg/kg PO once daily | PO | q24h | 6-12 months | 🌎 NA |
| Sporotrichosis | 5-10 mg/kg once daily | PO | q24h | 30 days beyond complete resolution of detectable lesions | 🌎 NA |
| Cryptococcosis (mild to moderate, no CNS involvement) | Cats <= 3.5 kg: 50 mg PO once daily or 100 mg PO every other day; Medium/large cats: 100 mg PO once daily | PO | q24h or q48h | 3-12 months | 🌎 NA |
| Coccidioidomycosis | 25-50 mg (total dose) per cat q12-24h | PO | q12-24h | — | 🌎 NA |
| Generalized dermatophytosis (Microsporum canis) | 5 mg/kg PO once daily preferably between meals for 7 days on, 7 days off; repeat 3 times | PO | q24h (pulse) | 5 weeks (treated weeks 1, 3, 5) | 🌎 NA |
| Generalized dermatophytosis (Alternative) | 5 mg/kg PO twice daily or 10 mg/kg | PO | q12h or q24h | Generally 3-5 weeks | 🌎 NA |
| Dermatophyte granuloma | 10 mg/kg PO once daily | PO | q24h | Weeks to months | 🌎 NA |
| Dermatophytosis (Pulse therapy) | 5 mg/kg PO once daily on an every other week schedule | PO | q24h (pulse) | Three 'pulses' of one week on, one week off | 🌎 NA |
| General use (fungal infections) | 5 mg/kg | PO | q24h | 4-20 weeks of treatment may be needed, dependent upon culture results | 🌍 EU |
| Dermatophytosis (Microsporum canis) | 5 mg/kg | PO | q24h | Pulse dosing: 7 days on, 7 days off repeated x3 | 🌍 EU |
- Histoplasmosis: Given with food. Can also be divided twice daily.
- Cryptococcosis: If response inadequate, may add flucytosine.
- Blastomycosis: Cats usually require longer treatment than dogs.
- Cryptococcosis (mild to moderate, no CNS involvement): Give with food. Monitor ALT. Continue until completely normal, then check antigen titer.
- Generalized dermatophytosis (Alternative): Give with food. Give until culture is negative 2 times at two week intervals.
- Dermatophyte granuloma: At least one month beyond clinical resolution and until brush culture is negative x 2.
- Dermatophytosis (Microsporum canis): Authorized in the form of an oral solution. Used successfully to treat ringworm in Persian cats without the need for clipping.
小型哺乳類
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Blastomycosis (Mice) | 50-150 mg/kg q24h | PO | q24h | — | 🌎 NA |
| Vaginal candidiasis (Rats) | 2.5-10 mg/kg q24h | PO | q24h | — | 🌎 NA |
| Systemic candidiasis (Guinea pigs) | 5 mg/kg q24h | PO | q24h | — | 🌎 NA |
鳥
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Fungal infections in Ratites | 6-10 mg/kg PO once daily | PO | q24h | — | 🌎 NA |
| Fungal diseases | 5-10 mg/kg PO q12-24h | PO | q12-24h | — | 🌎 NA |
| Aspergillosis (Amazon parrots) | 5-10 mg/kg PO once daily | PO | q24h | — | 🌎 NA |
| Aspergillosis (African grey Parrots) | 2.5-5 mg/kg PO once daily | PO | q24h | — | 🌎 NA |
- Fungal infections in Ratites: If neuro signs develop reduce dose or discontinue.
- Fungal diseases: Use with caution in African grey parrots.
馬
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Guttural pouch mycosis, mycotic rhinitis or osteomyelitis | 5 mg/kg PO q24h | PO | q24h | — | 🌎 NA |
- Guttural pouch mycosis, mycotic rhinitis or osteomyelitis: Using the oral solution should be sufficient for treatment.
用量は獣医専門家向けの臨床参考資料です。必ず最新の医薬品情報および個別症例に基づいて確認してください。
概要
イトラコナゾールは、合成された高親油性の経口トリアゾール系抗真菌薬であり、獣医学において全身性真菌症（アスペルギルス症、クリプトコッカス症、ブラストミセス症、ヒストプラズマ症など）や、表在性の皮膚糸状菌症およびマラセチア感染症の治療に広く使用されています。
臨床上のポイントと薬理学的特徴：
- 優れた有効性： ケトコナゾールなどの古いイミダゾール系と比較して有効性が高いとされ、哺乳類のホルモン合成をほとんど抑制しないため、内分泌系の副作用が少ないです。
- 組織移行性： 高い親油性と親ケラチン性を持つため、皮膚、皮脂、膿に高濃度で蓄積し、皮膚の真菌感染症に対して非常に効果的です。
- 製剤による違い： 吸収は製剤に大きく依存します。市販のカプセル剤は、最適な吸収のために酸性の胃内環境と食事を必要とします。市販の経口液剤は溶解性を高めるためにシクロデキストリンを含んでおり、空腹時の吸収が最も良好です。
- 調剤に関する警告： バルク粉末からの院内調剤は強く推奨されません。血中濃度が治療域に達しない、あるいは検出不能になることが多く、全身性真菌感染症においては致命的となる可能性があります。
作用機序
Itraconazole is a fungistatic triazole.
Mechanism of Action:
- Enzyme Inhibition: Itraconazole selectively inhibits the fungal cytochrome P450-dependent enzyme lanosterol 14α-demethylase.
- Pathway Disruption: This inhibition blocks the conversion of lanosterol to ergosterol (the primary sterol in fungal cell membranes) → leads to the accumulation of toxic 14α-methylsterols.
- Membrane Permeability: The lack of ergosterol alters the cellular membrane structure → increases membrane permeability → allows leakage of cellular contents and impairs the uptake of purine and pyrimidine precursors.
- Immunomodulation: Itraconazole also exhibits mild immune-suppressing activity, likely via the suppression of T-lymphocyte proliferation.
安全性・警告
禁忌
- Hypersensitivity to itraconazole or other azole antifungals
- Hepatic impairment (relative contraindication)
- Achlorhydria or hypochlorhydria (relative contraindication)
- Reduced cardiac function (relative, due to potential negative inotropic effects)
- Pregnancy
- Liver disease (avoid use if present)
有害事象
- Anorexia (most common in dogs)
- Hepatotoxicity (increased ALT, jaundice)
- Ulcerative skin lesions/vasculitis (dogs at high doses)
- Limb edema (dogs at high doses)
- Erythema multiforme (rare)
- Toxic epidermal necrolysis (rare)
- Vomiting
- Weight loss
- Depression (especially in cats and African grey parrots)
- Diarrhoea
- Salivation
- Depression and apathy
- Abdominal pain
- Hepatic toxicosis
- Ulcerative dermatitis
- Limb oedema
- Serious cutaneous drug eruptions (occasional)
- Dose-related suppression of adrenal function
注意事項
Use with caution in patients with hepatic impairment, achlorhydria, or reduced cardiac function (due to potential negative inotropic effects). African grey parrots are extremely sensitive to itraconazole and can develop severe anorexia and depression; reduced dosages or alternative antifungals are recommended. Do not use compounded capsules from bulk powders, as they may not yield an absorbable dosage form, leading to treatment failure in life-threatening infections. Safety during pregnancy is not established (teratogenic and embryotoxic in lab animals at high doses).
医薬品相互作用
May be antagonistic against Aspergillus or Candida; clinical importance unclear.
May reduce oral absorption of itraconazole; administer itraconazole at least 1 hour before or 2 hours after antacids.
Itraconazole may increase benzodiazepine levels.
Plasma concentrations may be elevated.
Itraconazole may increase levels.
Itraconazole may increase levels.
Increased cisapride levels and possibility for toxicity; concurrent use contraindicated in humans.
May decrease metabolism and increase clomipramine levels.
May inhibit the metabolism of corticosteroids; potential for increased adverse effects.
May inhibit metabolism of cyclophosphamide and its metabolites; potential for increased toxicity.
Increased cyclosporine levels.
May increase digoxin levels; concurrent use considered contraindicated in humans.
May increase fentanyl or alfentanil levels.
Increased gastric pH may reduce itraconazole absorption.
May increase risk for neurotoxicity.
May increase itraconazole concentrations.
May decrease itraconazole levels.
Increased gastric pH may reduce itraconazole absorption.
Increased risk for quinidine toxicity.
May decrease itraconazole levels; itraconazole may increase rifampin levels.
May increase levels; hypoglycemia possible.
May inhibit vinca alkaloid metabolism and increase levels.
May cause increased prothrombin times in patients receiving warfarin or other coumarin anticoagulants.
Extends the activity of methylprednisolone
Inhibits metabolism, potentially leading to toxicity
Inhibits metabolism
Inhibits metabolism
Increases bioavailability and blood levels of ciclosporin (well-documented in cats)
Inhibits metabolism and increases plasma concentrations
Reduces the absorption of itraconazole
Reduces the absorption of itraconazole
Reduces the absorption of itraconazole
Increases plasma concentrations of benzodiazepines
Increases plasma concentrations of vincristine
Datasheet advises against concurrent administration in cats
Datasheet advises against concurrent administration in cats
監視
- Clinical Efficacy
- Liver function tests (monthly ALT recommended with long-term therapy)
- Appetite (anorexia is often the first sign of toxicity)
- Physical assessment for ulcerative skin lesions in dogs
- Liver enzymes (ALT, AST, ALP, Bilirubin) prior to and during prolonged treatment
- Clinical signs of hepatotoxicity (anorexia, vomiting, jaundice)
- Resolution of clinical signs and negative fungal cultures
薬物動態
吸収
Highly dependent on gastric pH and presence of food. Empty stomach bioavailability may be <50%; with food, it approaches 100%. The oral solution is better absorbed on an empty stomach and possesses adequate bioavailability. Compounded capsules from bulk powders may not be absorbed.
分布
Very high protein binding. Widely distributed to lipid-rich tissues (highly lipophilic). Skin, sebum, female reproductive tract, and pus have concentrations greater than serum. Minimal concentrations in CSF, urine, aqueous humor, and saliva.
代謝
Metabolized by the liver to many different metabolites, including the active metabolite hydroxyitraconazole.
消失
Elimination may be a saturable process. Because of its long half-life, steady-state plasma levels are not reached for at least 6 days without a loading dose.
過剰投与
There is very limited information on acute toxicity.
- Decontamination: Giving oral antacids may help reduce absorption. If a large overdose occurs, consider gut emptying and provide supportive therapy.
- Clearance: Itraconazole is not removed by dialysis.
- Chronic Toxicity: In studies, dogs receiving 40 mg/kg PO daily for 3 months demonstrated no overt toxicity.
製品
製剤
- Capsules
- 100 mg capsule
- 10 mg/ml oral solution
動物用医薬品
- Intrafungol® (Janssen) oral liquid 10 mg/mL (Available in UK/select countries)
- Itrafungol 10 mg/ml oral solution
ヒト用医薬品
- Sporanox® Capsules 100 mg (and generics)
- Sporanox® Oral Solution 10 mg/mL
- Sporanox 100 mg capsule
規制ステータス
POM-V
POM-V, POM
規制データなし: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
保管・安定性
Capsules should be stored between 15-25°C and protected from light and moisture. Oral solution should be stored at temperatures less than 26°C, and protected from freezing.
飼主向け情報
重要な投与指示：
- カプセル剤： 適切な吸収を確保するため、必ず食事と一緒に与えてください。猫や小型犬の場合は、カプセルを開けて中身のペレットを少量の美味しい食べ物（バター、チーズ、缶詰など）に混ぜて与えることができます。
- 経口液剤： 哺乳類の場合は、理想的には空腹時に与えてください。
注意すべき症状：
- 食欲不振は、薬が肝臓に影響を与えている最初の兆候であることが多いです。ペットが食事を摂らなくなった、嘔吐し始めた、または目や歯茎が黄色くなった（黄疸）ことに気づいた場合は、すぐに獣医師に連絡してください。
- 犬の場合は、原因不明の皮膚のただれや脚の腫れに注意してください。
安全上の警告：
- バルク粉末から調剤された薬は使用しないでください。吸収が非常に悪く、治療の失敗につながる可能性があり、重篤な真菌感染症においては非常に危険です。
- 獣医師の承認なしに、他の薬（特に制酸薬）と一緒に与えないでください。
VetSheet医薬品リファレンスは獣医専門家の臨床意思決定支援を目的としており、専門的判断または製造業者の最新医薬品情報の代替にはなりません。