チアミン (ビタミンB1)
Thiamine (Vitamin B1)
Thiamine hydrochloride
別名: Thiamilate · Horse Care Durvit B-1 Crumbles · Thia-Dex · Vitamin B-1 Powder · Vitamin B1 · Aneurine hydrochloride · Thiamin hydrochloride · Thiamine chloride · Thiamini hydrochloridum · Thiaminii chloridum · Thiamine hydrochloride
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 |
|---|---|---|---|---|---|
| Thiamine deficiency | 5-50 mg | IM, SC, or IV | Not specified | — | 🌎 NA |
| Thiamine deficiency | 1-2 mg | IM | Not specified | — | 🌎 NA |
| Thiamine deficiency | 2 mg/kg | PO | once daily | — | 🌎 NA |
| Thiamine deficiency | 100-250 mg | SC | twice daily | for several days until regression of symptoms with complete recovery | 🌎 NA |
| Adjunctive treatment for ethylene glycol toxicity | 100 mg/day | PO | daily | — | 🌎 NA |
- Thiamine deficiency: Depending on formulation
猫
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Thiamine deficiency | 100-250 mg | parenterally | twice a day | — | 🌎 NA |
| Thiamine deficiency | 10-20 mg/kg | IM | Not specified | for several days | 🌎 NA |
| Adjunctive treatment of hepatic lipidosis | 100 mg of thiamine in one liter of crystalloid fluids | IV | Not specified | — | 🌎 NA |
| Thiamine deficiency | 100-250 mg | SC | twice daily | for several days until regression of symptoms with complete recovery | 🌎 NA |
| Thiamine deficiency | 10-20 mg/kg IM or SC two to three times daily until signs abate, then 10 mg/kg PO once daily | IM, SC, PO | two to three times daily, then once daily | 21 days for PO phase | 🌎 NA |
- Thiamine deficiency: Experimentally, as little as 1 mg is effective
- Adjunctive treatment of hepatic lipidosis: With additional soluble B vitamins. Indicated if neck ventroflexion is present.
小型哺乳類
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Prophylaxis when animals with E. macusaniensis treated with amprolium for >5 days (Camelids) | 10 mg/kg | SC | q24h | after the 5th day of amprolium | 🌎 NA |
- Prophylaxis when animals with E. macusaniensis treated with amprolium for >5 days (Camelids): For Camelids (NWC)
馬
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Thiamine deficiency | 0.5-5 mg/kg | IV, IM or PO | Not specified | — | 🌎 NA |
| Thiamine deficiency | 100-1000 mg | IM, SC, or IV | Not specified | — | 🌎 NA |
| Adjunctive treatment of perinatal asphyxia syndrome (hypoxic ischemic encephalopathy) | 1 gram in one liter of fluids | IV | once a day | — | 🌎 NA |
| As part of a parenteral nutrition (PN) formula | 1-2 mL/45 kg daily | IV | daily | — | 🌎 NA |
- Thiamine deficiency: Depending on formulation
- Adjunctive treatment of perinatal asphyxia syndrome (hypoxic ischemic encephalopathy): For Foals
- As part of a parenteral nutrition (PN) formula: Using a specific B complex vitamin mix (thiamine 12.5 mg/mL) diluted in fluids or PN.
牛
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Polioencephalomalacia | Initially, 10 mg/kg IV; then, 10 mg/kg IM twice daily | IV, IM | twice daily | 2-3 days | 🌎 NA |
| Polioencephalomalacia | 10-20 mg/kg | IM or SC | 3 times daily | — | 🌎 NA |
| Polioencephalomalacia | 10 mg/kg | IV, IM | up to 4 times a day | — | 🌎 NA |
| Adjunctive therapy of lead poisoning | 2 mg/kg | IM | Not specified | — | 🌎 NA |
- Polioencephalomalacia: If no improvement within 4 days, may be advisable to recommend slaughter.
- Polioencephalomalacia: If giving IV dilute in isotonic saline or isotonic dextrose.
- Polioencephalomalacia: First dose may be given via slow IV and subsequent doses IM. Severely affected animals may benefit from corticosteroids and mannitol.
- Adjunctive therapy of lead poisoning: Given at same time as CaEDTA therapy; total daily dose 8 mg/kg
豚
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Thiamine deficiency | 5-100 mg | IM, SC, or IV | Not specified | — | 🌎 NA |
- Thiamine deficiency: Depending on formulation
羊
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Polioencephalomalacia | Initially, 10 mg/kg IV; then, 10 mg/kg IM twice daily | IV, IM | twice daily | 2-3 days | 🌎 NA |
| Thiamine deficiency | 20-200 mg | IM, SC, or IV | Not specified | — | 🌎 NA |
- Polioencephalomalacia: If no improvement within 4 days, may be advisable to recommend slaughter.
- Thiamine deficiency: Depending on formulation
ヤギ
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Polioencephalomalacia | Initially, 10 mg/kg IV; then, 10 mg/kg IM twice daily | IV, IM | twice daily | 2-3 days | 🌎 NA |
- Polioencephalomalacia: If no improvement within 4 days, may be advisable to recommend slaughter.
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
チアミン（ビタミンB1）は、炭水化物代謝および正常な神経機能に不可欠な水溶性ビタミンです。
主な臨床的ポイント：
- 欠乏の原因： 小動物では、通常、食事からの摂取不足（サプリメント無添加の全肉食、加熱により破壊された市販食など）や、チアミナーゼを含む食品（生魚など）の摂取によって生じます。反芻動物では、チアミナーゼを産生するルーメン細菌や、ワラビなどのチアミナーゼを含む植物の摂取に続発することが多く、大脳皮質壊死症（PEM）を引き起こします。
- 臨床症状： 胃腸症状（食欲不振、流涎）、重度の神経筋/中枢神経系症状（運動失調、発作、猫の頸部腹側屈曲、反射消失）、または不整脈として現れます。
- 補助的用途： エチレングリコール中毒（毒性のあるシュウ酸塩の生成を避けるための代謝経路の変更）および鉛中毒の管理に頻繁に使用されます。
- 臨床のヒント： 脳は炭水化物代謝に大きく依存しているため、中枢神経系はチアミン欠乏に対して非常に敏感であり、神経症状が現れた場合は迅速な補充が不可欠です。
作用機序
Thiamine is actively transported into cells where it combines with adenosine triphosphate (ATP) to form thiamine diphosphate (thiamine pyrophosphate or TPP).
- Enzymatic Co-factor: TPP is an essential coenzyme for several key metabolic enzymes, including pyruvate dehydrogenase, alpha-ketoglutarate dehydrogenase (both critical for the Krebs cycle/aerobic energy production), and transketolase (pentose phosphate pathway).
- Metabolic Pathway: Glucose → Pyruvate. Without TPP, pyruvate cannot be converted into acetyl-CoA.
- Pathophysiology of Deficiency: Diminished NADH production forces the cell into anaerobic glycolysis, converting accumulated pyruvic acid into lactic acid → Lactic acidosis and cellular energy failure (especially in high-demand tissues like the brain and heart).
安全性・警告
禁忌
- Known hypersensitivity to thiamine or any of its components
有害事象
- Hypersensitivity or anaphylactic reactions (rare)
- Vasovagal anaphylactic response in cats (cardiac arrest, severe bradycardia, apnea, hypotension, collapse) when given SC (rare)
- Injection site tenderness or muscle soreness (IM)
- Pain at the injection site (IM/SC)
- Anaphylaxis or hypersensitivity reactions (primarily with rapid IV administration)
注意事項
Anaphylaxis Warning: Hypersensitivity reactions, though rare, can occur. A severe vasovagal anaphylactic response has been noted in a small number of cats following subcutaneous administration.
- Administration: Intravenous administration should be performed slowly or diluted in fluids to minimize adverse cardiovascular reactions.
- Laboratory Interference: May cause false-positive serum uric acid results (phosphotungstate method) and urobilinogen urine spot tests (Ehrlich's reagent). Large doses may interfere with theophylline concentration assays (Schack and Wexler method).
医薬品相互作用
Thiamine may enhance the activity of neuromuscular blocking agents; clinical significance is unknown.
監視
- Clinical efficacy (resolution of neurologic, gastrointestinal, or cardiac signs)
- Electrolyte levels (potassium, phosphate, magnesium) if treating conditions like feline hepatic lipidosis
- Resolution of clinical signs of thiamine deficiency (e.g., neurological improvement)
- Dietary intake and nutritional balance
薬物動態
半減期
吸収
Thiamine is readily absorbed from the gastrointestinal tract.
分布
Widely distributed to most body tissues.
代謝
Metabolized by the liver.
消失
Elimination is primarily renal, with the majority of the drug eliminated as metabolites.
過剰投与
Very large doses of thiamine in laboratory animals have been associated with neuromuscular or ganglionic blockade, though the clinical significance in veterinary patients is unknown.
- Massive Doses: May cause hypotension and respiratory depression.
- Lethal Dose: A lethal dose of 350 mg/kg has been reported.
- Treatment: Generally, no specific treatment is required for most overdoses due to its water-soluble nature and rapid renal excretion.
製品
製剤
- Injection: 100 mg/mL, 200 mg/mL, 500 mg/mL
- Tablets: 50 mg, 100 mg, 250 mg
- Enteric Coated Tablets: 20 mg
- Oral Powder/Crumbles/Supplement
- Injectable: 100 mg/ml solution
- Oral: various tablets, capsules, and liquids
動物用医薬品
- Thiamine HCl for Injection: 200 mg/mL in 100 mL and 250 mL vials
- Thiamine HCl for Injection: 500 mg/mL in 100 mL vials
- Thiamine HCl Dietary Supplement: 8,200 mg per lb (Horse Care Durvit B-1 Crumbles)
- Thiamine HCl Supplement: 500 mg/oz (Thia-Dex, Vitamin B-1 Powder)
- 100 mg/ml injectable solution (authorized for farm animals)
ヒト用医薬品
- Thiamine Tablets: 50 mg, 100 mg & 250 mg
- Thiamine Enteric Coated Tablets: 20 mg (Thiamilate)
- Thiamine HCl Injection: 100 mg/mL in 1 mL and 2 mL vials
- Various oral supplements (tablets, capsules)
規制ステータス
プール期間: cattle meat 0 days · cattle milk 0 hours
Injectable formulations are authorized for veterinary use in farm animals (POM-V). Oral forms are widely available on general sale.
プール期間: cattle meat 0 days · cattle milk 0 hours
Injectable formulations are POM-V (authorized for farm animals), while various oral formulations are available on general sale.
規制データなし: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
保管・安定性
Protect from light and store at temperatures less than 40°C (preferably between 15-30°C); avoid freezing. Thiamine HCl is unstable in alkaline or neutral solutions, or with oxidizing/reducing agents. It is most stable at a pH of 2.
飼主向け情報
- 食事管理： ペットにはバランスの取れた市販の食事を与えてください。生魚や完全な生肉食はチアミンを破壊し、重度の欠乏症を引き起こす可能性があるため避けてください。
- 投薬： 獣医師からチアミンが処方された場合は、指示通りに正確に投与してください。服用を忘れないようにしてください。
- 観察： 脱力感、ふらつき、発作の兆候が見られた場合、または猫の頭が胸の方に垂れ下がっている（頸部腹側屈曲）場合は、すぐに獣医師に連絡してください。
- 原因調査： 再発を防ぐために、欠乏症の原因（食事、特定の植物へのアクセス、生魚など）に関する疫学的調査を行い、必要な変更を加える必要があります。
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。