ビタミンA / イソトレチノイン
Vitamin A
Retinol, Isotretinoin, Tretinoin
別名: Roaccutane · Isotrexin · Vitamin E suspension · Retinol · Isotretinoin · 13-cis retinoic acid · all-trans retinoic acid · Alpha-tocopherol · Tocopheryl acetate
VetSheet 獣医チームが監修更新日 2026年4月5日エビデンスに基づく獣医学リファレンス
監査済み v13 用量エビデンス
確認済み・計算対象外のエビデンス確認済み・計算対象外のエビデンス (3)
エビデンス表示のみ（自動計算対象外）
[not stated in source table]
TABLE 128.6. Agent: Vitamin A (Aquasol A, 50,000 U/mL, Mayne Pharma). Dosage: 1 U/g PO daily × 14 days. Species/Comments: [not stated in source table]. Reference: 52. Table note: SC can be administered into the dorsal lymph sac of anurans..
エビデンス表示のみ（自動計算対象外）
African foam-nesting frogs/weight range, 2–7 g; dosing q48h and once weekly significantly increased whole body vitamin A levels over control group and group treated with vitamin A fortified supplement dusted over crickets
TABLE 128.6. Agent: Vitamin A (Aquasol A, 50,000 U/mL, Mayne Pharma). Dosage: Dilute 1 : 10 in sterile water; applied as one drop from 18-g needle; estimated as 50 U/frog q48h to q7d. Species/Comments: African foam-nesting frogs/weight range, 2–7 g; dosing q48h and once weekly significantly increased whole body vitamin A levels over control group and group treated with vitamin A fortified supplement dusted over crickets. Reference: 39. Table note: SC can be administered into the dorsal lymph sac of anurans..
エビデンス表示のみ（自動計算対象外）
Hypovitaminosis A; given the plethora of organ systems that hypovitaminosis A may affect, it is reasonable to institute vitamin A supplementation of any clinically ill amphibian, particularly ones with signs similar to “short tongue syndrome,” swollen eyelids, evidence of infectious dermatitis, hydrocoelom, or simply “failing to thrive”; the use of mixed dietary carotenoids may also be effective i
TABLE 128.6. Agent: Vitamin A (Aquasol A, 50,000 U/mL, Mayne Pharma). Dosage: Dilute 1 : 9 with sterile water; make fresh weekly; apply 1 drop from a tuberculin syringe with 27-g needle to amphibians under 5 g; 1 drop from tuberculin syringe without needle is about 200 U and useful for 15–30 g BW; >30 g, try 1 drop per 10 g BW; topically q24h × 14 days, then q4–7d. Species/Comments: Hypovitaminosis A; given the plethora of organ systems that hypovitaminosis A may affect, it is reasonable to institute vitamin A supplementation of any clinically ill amphibian, particularly ones with signs similar to “short tongue syndrome,” swollen eyelids, evidence of infectious dermatitis, hydrocoelom, or simply “failing to thrive”; the use of mixed dietary carotenoids may also be effective in some species. Reference: 52; 8. Table note: SC can be administered into the dorsal lymph sac of anurans..
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
ビタミンAおよびその誘導体（イソトレチノインやトレチノインなどのレチノイド）は、上皮組織の成長と分化に不可欠な脂溶性ビタミン/ホルモンです。獣医療では、主にビタミンA欠乏症や脂腺炎などの特定の皮膚疾患の治療に使用されます。
警告： レチノイドには強い催奇形性があります。獣医師および飼い主は、特に妊娠中の女性への偶発的な曝露を防ぐため、細心の注意を払う必要があります。
作用機序
Acts as a nutritional fat-soluble hormone that regulates gene expression.
Tretinoin (all-trans retinoic acid) is the acid form of vitamin A, and isotretinoin (13-cis retinoic acid) is an isomer of tretinoin.
Clinical Pearl: They bind to intracellular retinoic acid receptors (RARs) and retinoid X receptors (RXRs) → modifying gene transcription → regulating epithelial cell growth, differentiation, and sebum production.
安全性・警告
禁忌
- Pregnant animals
- Breeding animals
- Patients at high risk for thrombosis
- Neonates
有害事象
- Teratogenicity (fetal malformations)
- Keratoconjunctivitis sicca (KCS / dry eye)
- Hepatotoxicity
- Hyperlipidaemia
- Hypercalcaemia (due to bone calcium loss with prolonged use)
- Skin redness and pigmentation
- Haematological abnormalities
- Nervous system changes
- Bone changes
- Thrombosis
- Anaphylactoid reactions
注意事項
TERATOGENIC WARNING: Gloves should be worn when applying topical preparations. Pregnant women should avoid handling these medications entirely.
- Avoid contact with eyes, mouth, or mucous membranes.
- Avoid concurrent use of oral and topical preparations due to cumulative toxicity.
- Do not use formulations of vitamins A, D3, and E authorized for farm animals or horses in small animals, as they are too concentrated and risk severe toxicity.
- Minimize exposure of the drug to sunlight.
医薬品相互作用
Oral vitamin A may alter ciclosporin levels; requires close monitoring.
Do not use topical vitamin A preparations simultaneously with other topical drugs.
May enhance vitamin A absorption, utilization, and storage.
監視
- Signs of vitamin A toxicity
- Tear production (Schirmer Tear Test) for KCS
- Liver enzymes (ALT, AST, ALP)
- Serum calcium levels
- Serum triglycerides/lipids
- Ciclosporin levels (if used concurrently)
- Ciclosporin blood levels (if used concurrently)
- Coagulation parameters (in patients at risk for thrombosis)
- Liver enzymes (if treating hepatopathy)
薬物動態
半減期
吸収
Requires bile and dietary fat for optimal intestinal absorption.
分布
Widely distributed; stored primarily in adipose tissue, liver, and muscle.
代謝
Metabolized in the liver.
消失
Excreted primarily in feces via bile; a small amount is excreted in urine.
過剰投与
High doses or prolonged use can lead to severe vitamin A toxicity.
Signs of toxicity include:
- Hepatotoxicity
- Hyperlipidaemia
- Hypercalcaemia (due to promotion of calcium loss from bone)
- Severe skin, haematological, and nervous system abnormalities.
Treatment: Discontinue the drug immediately and provide supportive care. Monitor liver enzymes and serum calcium.
製品
製剤
- Injectable: 50,000 IU/ml (retinol)
- Oral capsules: 10 mg, 20 mg (isotretinoin)
- Topical gel: 0.05% (isotretinoin)
- Oral suspension: 20 mg/ml
- Oral suspension: 100 mg/ml
- Injectable preparations (often combined with selenium for large animals)
- Nutraceuticals (often combined with SAMe)
動物用医薬品
- Vitamin E suspension 20 mg/ml (POM-VPS)
- Vitamin E suspension 100 mg/ml (POM-VPS)
- Various nutraceutical combinations (e.g., with SAMe)
ヒト用医薬品
- Roaccutane (10 mg, 20 mg isotretinoin capsules)
- Isotrex (0.05% isotretinoin gel)
- Isotrexin (0.05% isotretinoin gel)
- Various oral capsules and liquid preparations
規制ステータス
Classified as POM-VPS in some regions for specific veterinary formulations.
Classified as POM-VPS.
規制データなし: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
保管・安定性
Minimize exposure of the drug to sunlight.
飼主向け情報
重大な警告： この薬は重篤な先天性異常を引き起こす可能性があります。妊娠中または妊娠を希望する女性は、この薬やペットの治療部位の皮膚に絶対に触れないでください。
- 外用ゲルを塗布する際は、必ず使い捨て手套を着用してください。
- ペットが妊娠している場合、または繁殖を予定している場合は、この薬を使用しないでください。
- ペットの目を注意深く観察してください。この薬は涙の脂質成分を変化させ、重度のドライアイを引き起こす可能性があります。目を細める、充血、またはドロドロした目やにに気づいた場合は、獣医師に連絡してください。
- 薬は直射日光を避けて保管してください。
- 獣医師の指示がない限り、同じ部位に他の外用薬を塗布しないでください。
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。