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S-アデノシルメチオニン (SAMe)

S-Adenosyl-Methionine (SAMe)

Ademetionine

肝保護薬 / 栄養補助食品PO犬猫

別名: Zentonil · Denamarin · Donamet · Gumbaral · Isimet · MoodLift · S Amet · Samyr · Transmetil · Tunik · Samylin · Hepatosyl · S-adenosyl-L-methionine · Sadenosylmethionine · SAM-e · Sammy · methioninyl adenylate · SAMe · AdoMet · S-adenosylmethionine

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

18 mg/kg (or based on weight: <5.5 kg: 90 mg; 5.5-11 kg: 180-225 mg; 11-16 kg: 225 mg; 16-29.5 kg: 450 mg; 29.5-41 kg: 675 mg; >41 kg: 900 mg)PO· q24h (may divide q12h if giving >1 tablet)
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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
General dosing / Liver support18 mg/kg (or based on weight: <5.5 kg: 90 mg; 5.5-11 kg: 180-225 mg; 11-16 kg: 225 mg; 16-29.5 kg: 450 mg; 29.5-41 kg: 675 mg; >41 kg: 900 mg)POq24h (may divide q12h if giving >1 tablet)—🌎 NA
Liver Disease (necro-inflammatory/cholestatic, vacuolar hepatopathy)20 mg/kgPOq24h—🌎 NA
Liver disease, cognitive dysfunction, adjunctive therapyAt least 100 mg for every 10 kg or 20 mg/kgPOq24hLong-term as needed🌍 EU
  • General dosing / Liver support: Give on an empty stomach, at least one hour before feeding.
  • Liver Disease (necro-inflammatory/cholestatic, vacuolar hepatopathy): Give on an empty stomach; use a proven bioavailable product.
  • Liver disease, cognitive dysfunction, adjunctive therapy: Administer on an empty stomach at least 1 hour before food. Tablets should be given whole.

猫

適応用量経路頻度期間地域
General dosing / Liver support18 mg/kg (or based on weight: <5.5 kg: 90 mg; 5.5-11 kg: 180-225 mg)POq24h—🌎 NA
Liver Disease (necro-inflammatory/cholestatic, feline hepatic lipidosis)20 mg/kgPOq24h—🌎 NA
Liver disease, cognitive dysfunction, improve bile flow100 mg/cat or 20 mg/kgPOq24hLong-term as needed🌍 EU
  • General dosing / Liver support: Give on an empty stomach, at least one hour before feeding.
  • Liver Disease (necro-inflammatory/cholestatic, feline hepatic lipidosis): Give on an empty stomach; use a proven bioavailable product.
  • Liver disease, cognitive dysfunction, improve bile flow: Administer on an empty stomach at least 1 hour before food. Tablets should be given whole.

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

​S-アデノシルメチオニン (SAMe)​ は、体内に自然に存在する内因性分子であり、主に​肝保護薬​として獣医療で広く利用されている栄養補助食品です。

主な臨床応用：

  • ​肝疾患​：慢性肝炎、肝リピドーシス、胆管肝炎、猫の三臓器炎などの補助治療として使用されます。
  • ​中毒の管理​：枯渇したグルタチオンを補充することにより、​アセトアミノフェン​や​キシリトール​中毒などの急性肝毒性物質による肝障害の治療において重要な役割を果たします。
  • ​その他の用途​：変形性関節症、加齢に伴う認知機能障害（犬の認知機能障害症候群）、および肝毒性の可能性がある薬剤（フェノバルビタールなど）を長期投与されている患者にも有益な場合があります。

​臨床のポイント​：純粋なSAMeは非常に反応性が高く不安定であるため、市販の製剤は安定性を向上させるために様々な塩（トシル酸塩など）を使用しています。製品間で生物学的利用能に大きな差があるため、信頼性の高い獣医療専用ブランドを選択することが強く推奨されます。

作用機序

SAMe is synthesized from the amino acid methionine and ATP via the enzyme SAMe synthetase. In liver compromise, this enzyme's activity is a rate-limiting step, leading to systemic SAMe deficiency. Exogenous SAMe bypasses this block and participates in three major biochemical pathways:

  • Transsulfuration → Generates sulfur-containing compounds → Precursor to ​Glutathione (GSH)​. Glutathione is the liver's master antioxidant, essential for ROS scavenging and cellular detoxification. Exogenous SAMe prevents GSH depletion.
  • Transmethylation → Serves as a methyl donor → Essential for phospholipid synthesis (e.g., phosphatidylcholine) → Maintains cell membrane structure, fluidity, and function.
  • Aminopropylation → Donates aminopropyl groups → Source of polyamines → Promotes anti-inflammatory effects, protein/DNA synthesis, and hepatocyte replication/regeneration.

Additionally, SAMe inhibits hepatocyte apoptosis secondary to alcohol or bile acid accumulation.

安全性・警告

禁忌

  • Use with caution in pregnant animals (safety not definitively proven)
  • No absolute contraindications documented
  • Use with caution during pregnancy (safety not established)

有害事象

  • Immediate post-dose vomiting
  • Anorexia
  • Nausea (reported in humans)
  • Diarrhea (reported in humans)
  • Flatulence (reported in humans)
  • Diarrhoea
  • Paradoxical anxiety
  • Dry mouth (reported in humans)
  • Headache (reported in humans)
  • Sweating (reported in humans)
  • Dizziness (reported in humans)

注意事項

There are no apparent absolute contraindications to the use of SAMe.

Pregnancy/Nursing: The safety of exogenous SAMe has not been definitively proven in pregnancy; use with caution. However, limited studies in laboratory animals and pregnant women with liver disease have not demonstrated ill effects. It is unknown if SAMe enters maternal milk.

医薬品相互作用

TramadolMajor

Theoretical risk of additive serotonergic effects (serotonin syndrome)

MeperidineMajor

Theoretical risk of additive serotonergic effects

Dextromethorphan

Theoretical risk of additive serotonergic effects

PentazocineMajor

Theoretical risk of additive serotonergic effects

Monoamine oxidase inhibitors (MAOIs) (e.g., selegiline)

Theoretical risk of additive serotonergic effects

Selective serotonin reuptake inhibitors (SSRIs) (e.g., fluoxetine)

Theoretical risk of additive serotonergic effects

Tricyclic antidepressants (TCAs) (e.g., amitriptyline, clomipramine)

Theoretical risk of additive serotonergic effects

SelegilineMajor

Additive serotonergic effects; potential for serotonin syndrome

FluoxetineMajor

Additive serotonergic effects; potential for serotonin syndrome

ClomipramineMajor

Additive serotonergic effects; potential for serotonin syndrome

AmitriptylineMajor

Additive serotonergic effects; potential for serotonin syndrome

ParacetamolModerate

SAMe may increase the clearance of drugs undergoing hepatic glucuronidation

DiazepamModerate

SAMe may increase the clearance of drugs undergoing hepatic glucuronidation

MorphineModerate

SAMe may increase the clearance of drugs undergoing hepatic glucuronidation

監視

  • Clinical signs (appetite, activity, attitude)
  • Liver enzymes (ALT, AST, ALP, GGT)
  • Liver biopsies (if indicated)
  • Hepatic and erythrocyte glutathione levels (Note: may require 1-4 months before changes in lab values are noted)
  • Liver enzyme panel (ALT, AST, ALP, GGT)
  • Total bilirubin and bile acids
  • Clinical signs of cognitive improvement or behavioral changes
  • Signs of serotonin syndrome (agitation, tremors, hyperthermia) if used concurrently with serotonergic drugs

薬物動態

半減期

猫Short (rapidly metabolized)犬Short (rapidly metabolized)

吸収

Oral bioavailability is highly dependent on the stabilizing salt (tosylate ~1%, 1,4-butanedisulfonate ~5%). The presence of food in the gut substantially reduces absorption. Peak levels occur 1-6 hours post-dosing with enteric-coated tablets. Chewable formulations yield similar AUC but faster peak levels.

分布

Enters portal circulation after absorption.

代謝

Primarily metabolized in the liver.

消失

In humans, 17% of a radiolabeled dose is recovered in urine within 48 hours; 27% in feces.

過剰投与

SAMe appears to be quite safe. The LD50 in rodents exceeds 4.65 grams/kg. Toxicity studies in dogs and cats at usual prescribed dosages demonstrated no deleterious effects.

In the event of a massive overdose, mild gastrointestinal effects (nausea, vomiting, diarrhea) may be observed, but it is highly unlikely to require specific medical treatment beyond supportive care.

製品

製剤

  • Enteric-coated tablets
  • Chewable tablets
  • Oral tablets: 90 mg, 100 mg, 200 mg, 225 mg, 400 mg, 425 mg
  • Oral capsules: 50 mg, 100 mg, 200 mg
  • Oral powder: 75 mg, 150 mg, 300 mg, 400 mg
  • Nutraceutical mixtures (often combined with silybin/milk thistle)

動物用医薬品

  • Denosyl (Nutramax): 90 mg, 225 mg, & 425 mg enteric-coated tablets; 225 mg chewable tablets
  • Zentonil (Vetoquinol): 100 mg, 200 mg, and 400 mg tablets
  • Denamarin (Nutramax): Combination product containing SAMe and silybin (silymarin)
  • Denamarin (SAMe + Silybin)
  • Zentonil Advanced
  • Samylin
  • Hepatosyl

ヒト用医薬品

  • Various over-the-counter nutritional supplements (tablets/capsules of varying concentrations)
  • Various OTC SAMe dietary supplements (tablets and capsules)

規制ステータス

European Union✓ 承認済みEMA
🐕 Dogs🐈 Cats

Classified as GSL (General Sale List) / nutraceutical.

United Kingdom✓ 承認済みVMD
🐕 Dogs🐈 Cats

Classified as GSL (General Sale List) / nutraceutical.

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

保管・安定性

Store at room temperature. Avoid conditions of high temperature or humidity. SAMe is inherently unstable in acidic or aqueous environments; store in tightly sealed, moisture-resistant containers (keep in original blister packs until use).

飼主向け情報

ペットへのSAMeの与え方

  • ​タイミングが重要です​：錠剤は​空腹時​、できれば食事の少なくとも1時間前に与えてください。胃の中に食べ物があると、サプリメントの吸収率が大幅に低下します。
  • ​砕いたり割ったりしないでください​：チュアブル（噛める）タイプを使用している場合を除き、腸溶錠を砕いたり、割ったりしないでください。特殊なコーティングが胃酸から有効成分を守り、腸で適切に吸収されるようにしています。
  • ​保管方法​：与える直前まで、錠剤は元のブリスターパック（アルミ包装）に入れたままにしてください。SAMeは湿気や空気に非常に敏感で、外に出しておくとすぐに劣化してしまいます。
  • ​根気よく続けてください​：ペットの肝臓の血液検査の数値が改善するまでには数週間から数ヶ月かかることがありますが、元気や食欲の改善はもっと早く見られるかもしれません。

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。