ダントロレンナトリウム
Dantrolene Sodium
Dantrolene Sodium (Hydantoin derivative)
別名: Dantrium · Danlene · Dantamacrin · Dantralen · F-440 · F-368 · Dantrolene sodium
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 |
|---|---|---|---|---|---|
| Treatment of functional urethral obstruction due to increased external urethral tone | 1-5 mg/kg PO q8-12h | PO | q8-12h | — | 🌎 NA |
| Treatment of functional urethral obstruction due to increased external urethral tone | 1 mg/kg PO q8h | PO | q8h | — | 🌎 NA |
| Canine stress syndrome (CSS)/Malignant Hyperthermia (MH) - acute attack | 0.2-3 mg/kg IV | IV | Once/PRN | — | 🌎 NA |
| MH-like syndrome associated with hops (Humulus lupulus) ingestion | 2-3 mg/kg IV or 3.5 mg/kg PO as soon as possible after ingestion. | IV/PO | Once | — | 🌎 NA |
| Adjunctive treatment of rhabdomyolysis | 1.5 mg/kg PO q8h | PO | q8h | — | 🌎 NA |
| Adjunctive treatment of Black Widow Spider bite | 1 mg/kg IV ; followed by 1 mg/kg PO q4h | IV, then PO | q4h | — | 🌎 NA |
- Adjunctive treatment of rhabdomyolysis: From a case report; very intensive drug and supportive therapy used in this case.
猫
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Treatment of functional urethral obstruction due to increased external urethral tone | 0.5-2 mg/kg PO q12h OR 0.5-1 mg/kg IV | PO/IV | q12h | — | 🌎 NA |
| Treatment of functional urethral obstruction due to increased external urethral tone | 0.5-2 mg/kg PO three times daily | PO | TID | — | 🌎 NA |
| Treatment of functional urethral obstruction due to increased external urethral tone | 2-10 mg (total dose) PO three times daily | PO | TID | — | 🌎 NA |
| Treatment of functional urethral obstruction due to increased external urethral tone | 0.5-1 mg/kg PO q12h | PO | q12h | — | 🌎 NA |
- Treatment of functional urethral obstruction due to increased external urethral tone: IV product very expensive.
- Treatment of functional urethral obstruction due to increased external urethral tone: Given with either prazosin (0.5 mg/cat once to twice daily) or phenoxybenzamine (2.5-7.5 mg/cat once to twice daily).
馬
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Treatment of acute rhabdomyolysis | 15-25 mg/kg slow IV four times daily | IV | QID | — | 🌎 NA |
| Treatment of acute rhabdomyolysis | 2-4 mg/kg PO via nasogastric tube once daily | PO | SID | — | 🌎 NA |
| Prevention of recurrent exertional rhabdomyolysis in Thoroughbreds | 4 mg/kg PO in horses fasted (12-hour fast in study) prior to administration. | PO | Once | — | 🌎 NA |
| Prevention of rhabdomyolysis | 2 mg/kg PO once daily for 3-5 days and then every 3rd day for a month | PO | SID then q3d | 1 month | 🌎 NA |
| Prevention of rhabdomyolysis | 300 mg (total dose) PO once daily | PO | SID | — | 🌎 NA |
| Prevention of rhabdomyolysis | 500 mg (total dose) PO for 3-5 days and then 300 mg PO every third day. | PO | SID then q3d | — | 🌎 NA |
| Prevention of rhabdomyolysis | 800 mg (total dose); within 30 minutes prior to administration contents of capsules mixed with 9 mL tap water to make a suspension and given PO one hour before exercise. | PO | Once before exercise | — | 🌎 NA |
| Prevention of post-anesthetic myositis (PAM) | 6 mg/kg enterally (given via NG tube in study) 60 minutes prior to general anesthesia. | Enteral | Once | — | 🌎 NA |
| Prevention of post-anesthetic myositis (PAM) | 10 mg/kg PO (intragastric) 1.5 hours before surgery. | PO | Once | — | 🌎 NA |
| Prevention of post-anesthetic myositis (PAM) | 1.9 mg/kg loading | IV | Once | — | 🌎 NA |
| Prevention of post-anesthetic myositis (PAM) | 4 mg/kg | IV | Once | — | 🌎 NA |
- Prevention of rhabdomyolysis: Drug is diluted in normal saline and given via stomach tube. Monitor hepatic function.
- Prevention of rhabdomyolysis: May be preferable because the drug is hepatotoxic.
- Prevention of post-anesthetic myositis (PAM): Does not appear to prolong recovery time.
- Prevention of post-anesthetic myositis (PAM): Should give peak levels at the time surgery begins and maintain postulated therapeutic levels for an additional 2 hours. Additional doses of 2.5 mg/kg PO (intragastric) q60 minutes can be given.
- Prevention of post-anesthetic myositis (PAM): Will give therapeutic levels but will only persist for about 20 minutes.
- Prevention of post-anesthetic myositis (PAM): Will maintain therapeutic levels for about 2 hours, but peak levels will be quite high.
豚
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Prevention or treatment of malignant hyperthermia | 3.5 mg/kg IV | IV | Once/PRN | — | 🌎 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
ダントロレンナトリウムは、ユニークな直接作用型の骨格筋弛緩薬です。中枢性筋弛緩薬（メトカルバモールやジアゼパムなど）とは異なり、末梢の筋線維に直接作用します。
獣医療における主な適応症は以下の通りです：
- 悪性高熱症（MH）： 特に豚や犬における悪性高熱症および豚ストレス症候群の救命薬。
- 馬の筋疾患： 馬の労作性横紋筋融解症（タイイングアップ）や麻酔後筋炎（PAM）の予防および治療に広く使用されます。
- 小動物の泌尿器科： 犬や猫の外尿道括約筋の緊張を低下させることによる機能性尿道閉塞の管理に頻繁に利用されます。
- 毒素咬傷： 大量のセチルコリン放出と重度の筋肉の痙攣を引き起こすクロゴケグモ咬傷の補助治療として推奨されます。
臨床のポイント： 注射剤は非常に高価であり、溶解後の使用期限が短いため、通常は重度で急性の危機（MHなど）に限定して使用され、経口剤は慢性的な管理や予防に使用されます。
作用機序
Dantrolene acts intracellularly to uncouple the excitation-contraction process in skeletal muscle.
- It binds specifically to the ryanodine receptor (RyR1) located on the sarcoplasmic reticulum (SR).
- This binding blocks the release of calcium (Ca²⁺) from the SR into the myoplasm.
- Decreased intracellular calcium → prevents the interaction of actin and myosin → produces skeletal muscle relaxation.
Because it specifically targets the RyR1 isoform (found primarily in skeletal muscle) rather than RyR2 (cardiac muscle), it has minimal direct effects on cardiac or smooth muscle at standard therapeutic doses. The exact mechanism for its mild CNS effects (drowsiness, dizziness) remains poorly understood.
安全性・警告
禁忌
- Preexisting liver disease (use with extreme caution)
- Severe cardiac dysfunction (use with caution)
- Pulmonary disease (use with caution)
有害事象
- Weakness
- Sedation
- Dizziness
- Headache
- Nausea
- Vomiting
- Constipation
- Increased urinary frequency
- Hypotension
- Hepatotoxicity (especially with chronic use)
注意事項
Hepatotoxicity Warning: Dantrolene can cause hepatotoxicity. It should be used with extreme caution in patients with preexisting liver disease. Monitor liver enzymes closely during chronic therapy.
- Use with caution in patients with severe cardiac dysfunction or pulmonary disease.
- Pregnancy: FDA Category C (human); Papich Class C (veterinary). Use cautiously as a last resort when benefits clearly outweigh risks.
- Nursing: Distributed into milk; safe use cannot be assured during nursing.
医薬品相互作用
Increased sedation may be seen if tranquilizing agents are used concomitantly.
Rare reports of cardiovascular collapse in humans; concomitant use during malignant hyperthermia crises is not recommended.
Increased risks of hepatotoxicity have been seen in women >35 years of age; veterinary significance is unknown.
Dantrolene may be displaced from plasma proteins by warfarin, resulting in increased effects or adverse reactions.
監視
- Baseline and periodic liver function tests (ALT, AST, Alk Phos, etc.) if projecting to be used chronically or using high dosages
- Body temperature (especially for malignant hyperthermia)
- Urine volume, frequency, continence
薬物動態
半減期
吸収
Bioavailability after oral administration is ~35% in humans and ~39% in horses (intragastric). Fairly slowly absorbed; peak levels occur ~5 hours post-oral dose in humans and 1.5 hours in horses. In horses, oral absorption is affected by food and must be given to a fasted horse to achieve therapeutic levels.
分布
Substantially bound to plasma proteins (principally albumin). Many drugs may displace it.
代謝
Metabolized in the liver.
消失
Metabolites are excreted in the urine. Only about 1% of the parent drug is excreted unchanged in the urine and bile.
過剰投与
There is no specific antidotal therapy for dantrolene overdoses.
- Decontamination: Remove the drug from the gut if possible (e.g., emesis induction, activated charcoal) if exposure was recent and oral.
- Supportive Care: Treat supportively, monitoring respiratory, cardiovascular, and hepatic function.
製品
製剤
- Oral Capsules
- Powder for Injection Solution
ヒト用医薬品
- Dantrolene Sodium Oral Capsules: 25 mg, 50 mg, & 100 mg (Dantrium; generic)
- Dantrolene Sodium Powder for Injection Solution: 20 mg/vial (approx. 0.32 mg/mL dantrolene after reconstitution; with mannitol 3 g/vial) in 70 mL vials (Dantrium Intravenous)
規制ステータス
POM (Prescription Only Medicine)
POM (Prescription Only Medicine)
規制データなし: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
保管・安定性
Capsules should be stored in well-closed containers at room temperature. Powder for injection should be stored at temperatures less than 30°C and protected from prolonged exposure to light. After reconstitution, the powder for injection should be used within 6 hours when stored at room temperature and should be protected from direct light. It is NOT compatible with either normal saline or D5W injection.
飼主向け情報
- 予想される副作用： ダントロレンは、軽度の胃腸の不調（嘔吐、食欲不振）、頻尿、および鎮静（眠気や脱力感）を引き起こす可能性があります。
- 肝臓に関する警告： まれに肝毒性を引き起こすことがあります。持続的な嘔吐、食欲不振、原因不明の極度の無気力、または白目や歯茎の黄疸が見られた場合は、直ちに獣医師に連絡してください。
- 投与について： 本薬の静脈内投与は、その使用とモニタリング要件に熟練した獣医療の専門家のみが行うべきです。
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。