ジアゼパム
Diazepam
7-chloro-1-methyl-5-phenyl-1,3-dihydro-2H-1,4-benzodiazepin-2-one
別名: Valium · Diastat · Diazepam Intensol · Diazedor · Diazemuls · Stesolid · Diazepam Rectubes · diazepamum · LA-III · NSC-77518 · Ro5-2807
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
監査済み v13 用量エビデンス
確認済み・計算対象外のエビデンス確認済み・計算対象外のエビデンス (1)
エビデンス表示のみ（自動計算対象外）
Persistent seizures during an insulinoma hypoglycemic crisis despite IV dextrose
Diazepam if seizures persist despite IV dextrose
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
ジアゼパムは、獣医学において抗不安、筋弛緩、催眠、食欲増進、および抗けいれん作用のために広く利用される、古典的で長時間作用型のベンゾジアゼピン系誘導体です。
臨床上のポイント：
- てんかん管理： ジアゼパムは、てんかん重積状態や群発てんかんの緊急治療における第一選択薬です。しかし、作用時間が短く、急速に耐性が形成されるため、犬の長期的な維持抗けいれん薬としては一般的に無効です。
- 猫に関する注意事項： 猫では耐性の問題は少ないものの、特異体質による致命的な劇症肝壊死のリスクがあるため、経口投与は非常に議論の余地があります。
- 製剤の特徴： 注射剤にはプロピレングリコールが含まれており、静脈内へ急速に投与すると低血圧、徐脈、心毒性を引き起こす可能性があります。また、PVCプラスチックに吸着しやすいため、プラスチック製シリンジでの保管や標準的な輸液バッグによる長時間の投与には適していません。
作用機序
Diazepam exerts its effects by binding to specific allosteric sites on GABA-A receptors in the central nervous system (primarily in the limbic system, thalamus, and hypothalamus).
- Binding to the benzodiazepine site → enhances the affinity of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) for its receptor.
- This facilitation → increases the frequency of chloride channel opening → influx of chloride ions → neuronal hyperpolarization.
- The resulting hyperpolarization leads to profound CNS depression, producing anxiolytic, sedative, muscle relaxant, and anticonvulsant effects.
安全性・警告
禁忌
- Known hypersensitivity to benzodiazepines
- Cats exposed to chlorpyrifos (potentiates organophosphate toxicity)
- Significant liver disease (especially in cats)
- Intra-carotid artery injections (must be strictly avoided)
- CNS depression
- Respiratory depression
- Severe muscle weakness
- Hepatic impairment (may worsen hepatic encephalopathy)
- Long-term treatment of behavioural disorders (due to risks of disinhibition and interference with memory/learning)
有害事象
- Sedation and ataxia (most common)
- Dogs: Paradoxical CNS excitement/agitation (especially at doses >0.8 mg/kg)
- Dogs: Increased appetite
- Cats: Idiosyncratic hepatic failure (with oral use)
- Cats: Behavior changes (irritability, depression, aberrant demeanor)
- Horses: Muscle fasciculations, weakness, ataxia, recumbency (at doses >0.2 mg/kg)
- Hypotension and phlebitis (with rapid IV injection)
- Muscle weakness
- Paradoxical excitation and aggression (especially with rapid IV injection or oral overdose in dogs)
- Pain and erratic absorption (IM injection)
- Fulminant hepatic necrosis (cats, repeated oral dosing)
- Thrombophlebitis (associated with propylene glycol injectable formulations)
注意事項
Intravenous Administration: Inject IV slowly (over 1-3 minutes). Rapid injection, especially in small animals or neonates, may cause hypotension or cardiotoxicity secondary to the propylene glycol vehicle. Flush the IV catheter with fluids after administration to help prevent thrombophlebitis.
Feline Hepatotoxicity: Use in cats is controversial due to reports of serious, potentially fatal idiosyncratic hepatotoxicity associated with oral administration. Baseline and follow-up liver function tests are strongly recommended if used.
- Patient Selection: Use cautiously in patients with hepatic or renal disease, debilitated or geriatric patients, and those in coma, shock, or with significant respiratory depression.
- Behavioral Disinhibition: Use very cautiously in aggressive patients, as it may disinhibit anxiety that normally suppresses aggressive behavior.
- Working Animals: May impair the abilities of working animals.
- Toxicity Treatment: Do not use to treat paradoxical CNS stimulation caused by human sleep aids (zolpidem, eszopiclone); use phenothiazines or phenobarbital instead.
- Pregnancy: May be teratogenic (FDA Category D). Use during the first trimester only if benefits clearly outweigh risks.
医薬品相互作用
May increase diazepam levels
May decrease oral diazepam absorption
May increase diazepam levels by inhibiting metabolism
May decrease metabolism of benzodiazepines
Additive CNS depression effects may occur
May decrease diazepam levels
Diazepam may increase digoxin levels
May decrease the metabolism of benzodiazepines
May decrease oral diazepam absorption
May inhibit the metabolism of diazepam and increase levels
May decrease diazepam concentrations
May decrease diazepam concentrations
May increase diazepam levels
May induce hepatic microsomal enzymes and decrease the pharmacologic effects of benzodiazepines
Enhanced sedative effect
Enhanced sedative effect
Diazepam reduces the dose requirement of other anaesthetic agents
Can be used in combination for management of severe behavioural responses
Reverses the effects of diazepam (benzodiazepine antagonist)
監視
- Horses should be observed carefully after receiving this drug.
- Cats receiving oral diazepam must have baseline liver function tests. Repeat and discontinue drug if emesis, lethargy, inappetence, or ataxia develop.
- When used for seizure control in cats, obtain serum levels 5 days after beginning therapy (therapeutic goal: 200-700 ng/mL or 2500-700 nmol/L).
- Hepatic function (especially in cats)
- Respiratory rate and effort
- Level of CNS depression / sedation
- Seizure activity
薬物動態
半減期
吸収
Rapidly absorbed following oral administration (peak plasma levels within 30 mins to 2 hours). Slowly and incompletely absorbed following IM administration. Rectal bioavailability in dogs is <10% for parent drug, but ~80% when factoring in active metabolites. Intranasal bioavailability in dogs is ~80%.
分布
Highly lipid soluble and widely distributed throughout the body. Readily crosses the blood-brain barrier. Highly bound to plasma proteins (87% in horses, 98-99% in humans).
代謝
Metabolized in the liver to several pharmacologically active metabolites, including desmethyldiazepam (nordiazepam), temazepam, and oxazepam.
消失
Metabolites are conjugated with glucuronide and eliminated primarily in the urine.
過剰投与
When administered alone, diazepam overdoses are generally limited to significant CNS depression (confusion, coma, decreased reflexes, etc.). Hypotension, respiratory depression, and cardiac arrest have been reported in human patients, but are quite rare.
Treatment:
- Standard protocols for removing and/or binding the drug in the gut if taken orally (e.g., emesis, activated charcoal).
- Supportive systemic measures (fluids, respiratory support if needed).
- The use of analeptic agents (CNS stimulants like caffeine) is generally not recommended.
- Flumazenil (a specific benzodiazepine antagonist) may be considered for adjunctive treatment of severe overdoses.
製品
製剤
- Oral tablets
- Oral solution
- Injectable solution
- Rectal gel
- Injectable: 5 mg/ml emulsion (e.g., Diazemuls)
- Oral: 2 mg, 5 mg, 10 mg tablets
- Oral: 2 mg/5 ml solution
- Rectal: 2 mg/ml and 4 mg/ml solutions
- Rectal: 10 mg suppositories
動物用医薬品
- None (No veterinary-labeled products available)
- Diazedor
- Diazemuls
- Diazepam Rectubes
ヒト用医薬品
- Diazepam Oral Tablets: 2 mg, 5 mg, & 10 mg (Valium, generic)
- Diazepam Oral Solution: 1 mg/mL and 5 mg/mL (Diazepam Intensol)
- Diazepam Injection: 5 mg/mL
- Diazepam Rectal Gel: 2.5 mg, 10 mg, & 20 mg (Diastat)
- Stesolid
規制ステータス
POM-V, POM
POM-V, POM
規制データなし: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
保管・安定性
Store all products at room temperature (15°-30°C). Protect injection from freezing and light. Protect oral forms from light. Important: Diazepam adsorbs to plastic; do not store drawn up in plastic syringes or administer through PVC IV bags/tubing for prolonged periods.
飼主向け情報
- 保管： 子供や他のペットの手の届かない場所に保管してください。密閉容器に入れて保管してください。これは規制薬物です。
- 投与： 処方された通りに正確に投与してください。自宅でけいれん発作のために直腸内投与を行う場合は、獣医師の安全な投与方法の指示に注意深く従ってください。
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猫に関する重大な警告： 猫がこの薬を服用中に食欲不振、嘔吐、または白目や歯茎が黄色くなる（黄疸）症状を示した場合は、直ちに投薬を中止し、すぐに獣医師に連絡してください。これは重篤な肝障害の兆候である可能性があります。
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。