ピリドキシン (ビタミンB6)
Pyridoxine (Vitamin B-6)
Pyridoxine hydrochloride
別名: Aminoxin · Vitelle Nestrex · Vitamin B6 · adermine · pyridoxal-5-phosphate · pyridoxamine · pirodoxamina · piridossima · piridoxolum · piridossina
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
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 |
|---|---|---|---|---|---|
| Isoniazid (INH) toxicity | If quantity of INH ingested is known, give pyridoxine on a mg for mg (1:1) basis. If it is not known, give pyridoxine initially at 71 mg/kg as a 5-10% IV infusion over 30-60 minutes | IV | Once | — | 🌎 NA |
| To replace pyridoxine antagonized by crimidine ingestion | 20 mg/kg | IV | Once | — | 🌎 NA |
| To delay the development of cutaneous toxicity (PPES) associated with doxorubicin containing pegylated liposomes (Doxil®) | 50 mg | PO | q8h (three times daily) | During chemotherapy protocol period | 🌎 NA |
- Isoniazid (INH) toxicity: Some sources say it can be given as an IV bolus. Do not use injectable B-complex vitamins.
猫
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| To replace pyridoxine antagonized by crimidine ingestion | 20 mg/kg | IV | Once | — | 🌎 NA |
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
ピリドキシン（ビタミンB6）は、多くの代謝プロセスに不可欠な水溶性ビタミンです。獣医学における主な特定の適応症は、イソニアジド（INH）またはクリミジン中毒の解毒剤として、またリポソーム化ドキソルビシン（Doxil®）に関連する皮膚毒性（手足症候群）を遅らせることです。
臨床のポイント：バランスの取れた市販のフードを食べている犬や猫で食事性の欠乏症が起こることは極めてまれですが、重度の胃腸疾患を持つ猫ではピリドキシンの必要量が増加する可能性があります。さらに、インビトロ研究では、ピリドキシンが猫の乳腺腫瘍の増殖を抑制できることが示されています。
作用機序
Pyridoxine is converted in erythrocytes to pyridoxal phosphate and, to a lesser extent, pyridoxamine, which act as vital coenzymes for protein, lipid, and carbohydrate utilization.
- Neurotransmitter Synthesis: Required for the synthesis of GABA (gamma-aminobutyric acid) in the CNS, and the conversion of tryptophan → serotonin or niacin.
- Metabolic Pathways: Essential for glycogen breakdown, heme synthesis, and the conversion of oxalate → glycine.
- Toxicity Antidote: Acts as an antidote by directly enhancing the renal excretion of cycloserine and isoniazid.
安全性・警告
禁忌
- Documented hypersensitivity or sensitivity to pyridoxine
有害事象
- Paresthesias (reported in humans)
- Somnolence (reported in humans)
- Reduced serum folic acid levels
- Peripheral neuropathy (associated with massive overdoses)
注意事項
Weigh potential risks versus benefits in patients with documented sensitivity to pyridoxine. While very safe at recommended doses during pregnancy, very large doses during pregnancy can cause a pyridoxine dependency syndrome in neonates. Pyridoxine requirements of the dam may be increased during nursing.
医薬品相互作用
May cause increased pyridoxine requirements
May cause increased pyridoxine requirements
May cause increased pyridoxine requirements
May cause increased pyridoxine requirements
May cause increased pyridoxine requirements
May cause increased pyridoxine requirements
Pyridoxine may reduce levodopa efficacy (no interaction when levodopa is used with carbidopa)
High dose pyridoxine may decrease phenobarbital serum levels
High dose pyridoxine may decrease phenytoin serum concentration
監視
- Efficacy for intended use
- Neurologic signs (gait, coordination) if on high doses
薬物動態
吸収
Absorbed from the GI tract primarily in the jejunum. Malabsorption syndromes can significantly impair pyridoxine absorption.
分布
Pyridoxine is not bound to plasma proteins, but its active metabolite pyridoxal phosphate is completely bound to plasma proteins. Stored primarily in the liver with smaller amounts stored in the brain and muscle.
代謝
Biotransformed in the liver and various tissues to active coenzymes.
消失
Excreted almost entirely as metabolites into the urine.
過剰投与
Warning: While single overdoses are generally not problematic unless massive, chronic high doses can cause severe neurologic toxicity.
- Massive Acute Overdose: Laboratory animals given 3-4 grams/kg developed seizures and died.
- Chronic Overdose: Dogs (Beagles) repeatedly given 3 gram oral daily doses developed uncoordinated gait and neurologic signs. Neuronal lesions were noted in sensory, dorsal root ganglia, and trigeminal ganglia. Signs generally resolved over a 2-month drug-free period.
製品
製剤
- Enteric-coated tablets
- Injection
動物用医薬品
- No single ingredient veterinary-labeled pyridoxine products are available (found in combination products)
ヒト用医薬品
- Pyridoxine Tablets: 50 mg, 100 mg, 250 mg, & 500 mg
- Pyridoxine (as pyridoxal-5'-phosphate) Tablets (enteric-coated): 20 mg (Aminoxin®)
- Pyridoxine HCl Injection: 100 mg/mL in 1 mL vials
規制ステータス
規制データなし: 🇺🇸 US · 🇪🇺 EU · 🇬🇧 UK · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
保管・安定性
Tablets should be stored below 40°C (104°F), preferably between 15-30°C (59-86°F), in well-closed containers protected from light. Injection should be stored at the same temperatures, protected from light and freezing. Injection can be administered undiluted or added to commonly used IV solutions. Compatible with doxapram and 10% fat emulsion. Incompatible with alkaline or oxidizing solutions, and iron salts.
飼主向け情報
重要：ピリドキシンは一般的に非常に安全ですが、極端な高用量は神経損傷を引き起こす可能性があります。
- 獣医師に処方された用量を超えて与えないでください。
- ペットに歩行困難、つまずき、階段の昇り降りが困難になるなどの異常な神経症状が見られた場合は、直ちに獣医師に連絡してください。
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。