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シアノコバラミン（ビタミンB12）

Cyanocobalamin (Vitamin B12)

Cyanocobalamin

ビタミン / 栄養補助食品SCIMIVPO犬猫馬牛豚羊

別名: Cyanoject · Rubesol · Crysti · Crystamine · Amtech Vitamin B12 · Anivit B12 · Cobalaplex · Cyanocobalamin PXN-B12 · Neo-Cytamen · Vitbee · cobalamins · cyanocobalamine · cyanocobalaminum · cobamin · cianokobalaminas · cianocobalamina · cycobemin · Hydroxocobalamin

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

25 micrograms/kgSC/IM· once per week for 4-6 weeks, then once monthly thereafter· Lifelong therapy may be required
— 🐕

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
Cobalamin deficiency in dogs with severe GI disease (protein losing enteropathies, inflammatory bowel disease)25 micrograms/kgSC/IMonce per week for 4-6 weeks, then once monthly thereafterLifelong therapy may be required🌎 NA
Cobalamin deficiency associated with GI disease250-1200 micrograms (total dose)SConce weekly for 6 weeks, then every 14 days for 6 weeks, then one dose 30 days laterInitial 16-week protocol🌎 NA
Cobalamin deficiency associated with exocrine pancreatic insufficiency250-500 mcg (total dose)parenterallyrepeat treatment based upon serum levels—🌎 NA
  • Cobalamin deficiency in dogs with severe GI disease (protein losing enteropathies, inflammatory bowel disease): May take as long as 3-4 weeks to see a response.
  • Cobalamin deficiency associated with GI disease: Based on body size. Recheck serum cobalamin concentration one month after last dose. If normal, continue at least monthly. If subnormal, continue weekly or bi-weekly.

猫

適応用量経路頻度期間地域
Cobalamin deficiency in cats with IBD250-500 micrograms (total dose per cat)SConce per week for 6 weeks, then every 1-2 months—🌎 NA
Adjunctive treatment of idiopathic hepatic lipidosis250 micrograms (total dose)SConce per week6 weeks🌎 NA
Cobalamin deficiency associated with GI disease150-250 micrograms (total dose)SConce weekly for 6 weeks, then every 14 days for 6 weeks, then one dose 30 days laterInitial 16-week protocol🌎 NA
Cobalamin deficiency associated with exocrine pancreatic insufficiency100-250 micrograms (total dose)SConce weekly—🌎 NA
  • Adjunctive treatment of idiopathic hepatic lipidosis: Recheck serum B12 level in one to two weeks after cessation of treatment as some cats may need repeated administration.
  • Cobalamin deficiency associated with GI disease: Based on body size. Recheck serum cobalamin concentration one month after last dose.
  • Cobalamin deficiency associated with exocrine pancreatic insufficiency: Periodically assess cobalamin and folate levels.

馬

適応用量経路頻度期間地域
Vitamin B12 deficiency1-2 mL of a 1000 micrograms/mL injection (1000-2000 micrograms per horse)IM or SConce or twice weekly—🌎 NA
  • Vitamin B12 deficiency: Dosage may be repeated as indicated by condition or response.

牛

適応用量経路頻度期間地域
Treatment of vitamin B12 deficiency associated with cobalt deficiency0.2-0.4 mL of a 5000 micrograms/mL injection (1000-2000 micrograms)IM or SCweekly intervals if necessary—🌎 NA

豚

適応用量経路頻度期間地域
Vitamin B12 deficiency0.1-0.4 mL of a 5000 micro-grams/mL injection (500-2000 micrograms)IM or SCweekly intervals if necessary—🌎 NA

羊

適応用量経路頻度期間地域
Treatment of vitamin B12 deficiency associated with cobalt deficiency (Lambs)100 micrograms (total dose)injectiononce weekly—🌎 NA
Treatment of vitamin B12 deficiency associated with cobalt deficiency (Adult sheep)300 micrograms (total dose)injectiononce weekly—🌎 NA
Treatment of vitamin B12 deficiency associated with cobalt deficiency0.2-0.4 mL of a 5000 micrograms/mL injection (1000-2000 micrograms)IM or SCweekly intervals if necessary—🌎 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。

診察中ですか？VetSheet の AI が薬剤・用量・投与期間を構造化された診察記録に直接記入します。VetSheet の仕組みを見る

概要

シアノコバラミン（ビタミンB12）は、正常な細胞機能に不可欠な水溶性ビタミンです。

  • ​主な用途​: ビタミンB12欠乏症の注射治療。
  • ​欠乏の一般的な原因​: 膵外分泌不全（EPI）、炎症性腸疾患（IBD）、その他の吸収不良性消化管疾患。
  • ​種特異性​:
    • ​犬と猫​: 消化管/膵臓疾患に続発する欠乏症が多く見られます。ジャイアント・シュナウザーなどの犬種では、遺伝的な吸収障害（イメルスルンド・グラスベック症候群）を持つ場合があります。
    • ​反芻動物​: 第一胃の微生物がB12を合成するためにコバルトを必要とするため、食事中のコバルト欠乏に続発することがよくあります。

​臨床のポイント​: 人間とは異なり、犬や猫はTC1結合タンパク質を持たないため、吸収不良の状態ではわずか1〜2ヶ月でB12の貯蔵が急速に枯渇します（人間は1〜2年かかります）。

作用機序

Vitamin B12 acts as a crucial coenzyme for two major enzymatic pathways:

  1. Methylmalonyl-CoA mutase: Converts methylmalonyl-CoA → succinyl-CoA. (Deficiency leads to methylmalonic acidemia/aciduria).
  2. Methionine synthase: Catalyzes the remethylation of homocysteine → methionine, which is intimately linked with folate metabolism.
  • Required for normal cell growth, nucleoprotein and myelin synthesis, amino acid metabolism, and erythropoiesis.
  • Note: B12 deficiency can cause a functional folate deficiency. Unlike humans, macrocytic anemias do not appear to be a significant component of cobalamin deficiency in dogs or cats.

安全性・警告

禁忌

  • Hypersensitivity to cyanocobalamin or hydroxocobalamin
  • Known hypersensitivity to cobalt or cobalamin

有害事象

  • Pain at injection site (uncommon)
  • Anaphylaxis (rarely reported in humans)
  • Pain or stinging at the injection site
  • Mild allergic reactions (rare)

注意事項

Safe to use during pregnancy and nursing. Serum samples to be analyzed for cobalamin and/or folate should be protected from bright light and excessive heat.

医薬品相互作用

Antibiotics

Concurrent use can cause falsely low serum or red blood cell cobalamin values if a microbiologic method assay is used.

OmeprazoleMinor

May decrease oral absorption of Vitamin B12 by altering gastric pH

監視

  • Serum cobalamin levels
  • Serum folate status (both before and after treatment)
  • Clinical signs associated with deficiency (weight loss, poor haircoat, vomiting, diarrhea)
  • CBC (baseline and ongoing if abnormal)
  • Serum cobalamin (Vitamin B12) levels
  • Serum folate levels
  • Clinical signs of gastrointestinal disease (weight gain, fecal consistency)

薬物動態

半減期

猫Approximately 13 days (normal cats); 5 days (cats with IBD)犬Variable (depends on tissue stores)

吸収

Cobalamin in food binds to haptocorrin in the stomach → degraded by pancreatic proteases in the duodenum → binds to Intrinsic Factor (IF) (produced in stomach/pancreas in dogs, pancreas only in cats) → absorbed in the small intestine via cubulin → enters portal circulation.

分布

Binds to transcobalamin 2 (TCII) for entry into target cells. Dogs and cats lack cobalamin-binding protein TC1, leading to rapid depletion of stores (1-2 months) compared to humans (1-2 years).

代謝

Undergoes entero-hepatic recirculation.

消失

Rapidly excreted into the bile.

過剰投与

Cyanocobalamin is very safe. An inadvertent overdose given via SC or IM injection is unlikely to cause significant morbidity.

製品

製剤

  • Injection
  • Oral tablets (human-labeled, not recommended for small animal deficiency states)
  • Injectable: 0.25 mg/ml solution
  • Injectable: 1 mg/ml solution
  • Oral: 0.5 mg capsule

動物用医薬品

  • Cyanocobalamin (Vitamin B12) Injection 1000 micrograms/mL
  • Cyanocobalamin (Vitamin B12) Injection 3000 micrograms/mL
  • Cyanocobalamin (Vitamin B12) Injection 5000 micrograms/mL
  • Anivit B12 250
  • Anivit B12 1000
  • Cobalaplex
  • Cyanocobalamin PXN-B12
  • Vitbee 250
  • Vitbee 1000

ヒト用医薬品

  • Cyanocobalamin Injection 100 micrograms/mL
  • Cyanocobalamin Injection 1000 micrograms/mL
  • Oral tablets (not recommended for small animal deficiency states)
  • Neo-Cytamen (hydroxocobalamin)

規制ステータス

European Union✓ 承認済み処方箋医薬品EMA
🐕 Dogs🐈 Cats
United Kingdom✓ 承認済み処方箋医薬品 · POM-VPSVMD
🐕 Dogs🐈 Cats

Classified as POM-VPS in the UK.

規制データなし: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU

保管・安定性

Store below 40°C; protect from light and freezing. Cyanocobalamin injection is reportedly compatible with all commonly used intravenous fluids.

飼主向け情報

  • ​忍耐が必要です​: B12治療を開始してから、ペットの状態（体重増加、便の質の改善など）に顕著な改善が見られるまで数週間かかる場合があります。
  • ​長期的な治療​: 根本的な疾患（慢性の胃腸問題やEPIなど）によっては、​生涯にわたる​ビタミンB12の補充が必要になる場合があります。
  • ​自宅での投与​: 薬は皮下注射で投与されるため、獣医師から自宅で安全に注射を行う方法を指導してもらうことができます。

​重要​: 自宅で注射を行っている場合でも、B12レベルが適切に維持されていることを確認するために、定期的な診察と血液検査が不可欠です。

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