イミプラミン
Imipramine
Imipramine hydrochloride, Imipramine pamoate
別名: Tofranil-PM · imipramini chloridum · imipramini hydrochloridum · imizine · Antidep · Celamine · Depramina · Depsonil · Elepsin · Ethipramine · Imiprex · Imiprin · Imp-Tab · Impril · Janimine · Melipramine · Mipralin · Novo-Pramine · Praminan · Primonil · Pryleugan · Sermonil · Surplix · Talpramin · Imipraminum
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 |
|---|---|---|---|---|---|
| Urethral incompetence | 5-15 mg (total dose) | PO | q12h | — | 🌎 NA |
| Urinary incontinence when other agents fail | 5-20 mg (total dose) | PO | q12h | — | 🌎 NA |
| Cataplexy | 0.5-1 mg/kg | PO | q8h | — | 🌎 NA |
| Adjunctive treatment of separation anxiety or other tricyclic antidepressant-responsive behavior disorders | 2.2-4.4 mg/kg | PO | once to twice daily | — | 🌎 NA |
| Adjunctive cancer pain treatment | 0.5-1 mg/kg | PO | q8h | — | 🌎 NA |
| Anxiety, inappropriate urination, narcolepsy | 1-2 mg/kg | PO | q12h | — | 🌍 EU |
| Anxiety, inappropriate urination, narcolepsy | 2-4 mg/kg | PO | q24h | — | 🌍 EU |
- Cataplexy: Titrate dose based on clinical effect
- Anxiety, inappropriate urination, narcolepsy: Alternatively, 2-4 mg/kg p.o. q24h
- Anxiety, inappropriate urination, narcolepsy: Alternatively, 1-2 mg/kg p.o. q12h
猫
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Urethral incompetence | 2.5-5 mg (total dose) | PO | q12h | — | 🌎 NA |
| Adjunctive cancer pain treatment | 2.5-5 mg (total dose) | PO | q12h | — | 🌎 NA |
| Anxiety, inappropriate urination | 0.5-1 mg/kg | PO | q12-24h | — | 🌍 EU |
馬
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Pharmacologic induced ejaculation | 2 mg/kg | IV | once | — | 🌎 NA |
| Narcolepsy/cataplexy | 0.55 mg/kg IV or 250-750 mg (total dose) orally | IV, PO | once | — | 🌎 NA |
- Pharmacologic induced ejaculation: If imipramine alone does not induce erection and ejaculation in 10-15 minutes, give xylazine 0.2-0.3 mg/kg IV. (Note: ARCI UCGFS Class 2 Drug)
- Narcolepsy/cataplexy: PO administration produces inconsistent results.
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
イミプラミンは、獣医療において適応外使用される三環系抗うつ薬（TCA）です。主に分離不安などの行動学的問題に認識されていますが、そのユニークな受容体プロファイルにより非常に多用途です。
- 犬や猫では、尿失禁や情動脱力発作（カタプレキシー）の治療に頻繁に使用されます。
- 馬の医療では、ナルコレプシーの管理や薬理学的な射精の誘発に用いられます。
臨床のポイント：イミプラミンは第3級アミンTCAであり、肝臓で急速に活性を持つ第2級アミン代謝物であるデシプラミンに代謝されます。この二重の作用により、セロトニンとノルアドレナリンの両方の経路に影響を与え、薬理学的なスペクトルが広がります。
作用機序
Imipramine and its active metabolite, desipramine, exert their effects through a complex, multi-receptor pharmacologic profile:
- Monoamine Reuptake Inhibition: Blocks the presynaptic amine pump, preventing the reuptake of serotonin (5-HT) and norepinephrine (NE) → increases neurotransmitter concentrations in the synaptic cleft → modulates mood, arousal, and pain pathways.
- Anticholinergic Activity: Antagonizes muscarinic receptors centrally and peripherally. This mechanism is primarily responsible for its efficacy in treating urinary incontinence (facilitating urine storage by relaxing the detrusor muscle) and its common side effects (dry mouth, tachycardia).
- Alpha-Adrenergic Agonism/Antagonism: Exhibits complex interactions at alpha receptors, which may contribute to increasing internal urethral sphincter tone.
- Antihistaminic (H1) Activity: Contributes to its significant sedative properties.
安全性・警告
禁忌
- Prior sensitivity to any tricyclic antidepressant
- Concomitant use with monoamine oxidase inhibitors (MAOIs) within 14 days
- Glaucoma
- History of seizures
- Urinary retention
- Severe liver disease
- Hypersensitivity to tricyclic antidepressants
有害事象
- Sedation
- Dry mouth
- Constipation
- Tachycardia
- Hyperexcitability
- Tremors
- Seizures (CNS stimulation)
- Bone marrow suppression
- Diarrhea
- Vomiting
- Diarrhoea
- Arrhythmias
- Hypotension
- Syncope
- Increased appetite
注意事項
Use with extreme caution in patients with seizure disorders, as imipramine may lower the seizure threshold.
Pregnancy Warning: There are isolated reports of limb reduction abnormalities (teratogenic potential). Restrict use in pregnant animals to situations where benefits clearly outweigh the risks (FDA Category D in humans).
Nursing: Excreted into milk in low concentrations (milk:plasma ratio 0.4 to 1.5).
医薬品相互作用
Additive anticholinergic effects; use cautiously
May inhibit tricyclic antidepressant metabolism and increase the risk of toxicity
Additive CNS depressant effects; use cautiously
Imipramine may decrease levodopa oral absorption
May decrease tricyclic levels
Increased risk for QTc interval prolongation and tricyclic adverse effects
May decrease tricyclic blood levels
Increased risk for serotonin syndrome
May increase the risk of cardiac effects (arrhythmias, hypertension, hyperpyrexia)
Concomitant use (within 14 days) is generally contraindicated due to risk of serotonin syndrome
May increase risk for cardiac arrhythmias
Increased risk for prolonged QT interval
Tricyclics may increase blood pressure
High risk of fatal serotonin syndrome
Altered metabolism via cytochrome P450 2D6 competition/inhibition
Increased risk of serotonin syndrome
Increased risk of serotonin syndrome (use only in exceptional cases with careful monitoring)
監視
- Clinical efficacy
- Adverse effects
- ECG (Tricyclics can widen QRS complexes, prolong PR intervals, and invert or flatten T-waves)
- Blood Glucose (Tricyclics may increase or decrease blood glucose levels)
- Heart rate and rhythm (ECG) in susceptible patients
- Signs of serotonin syndrome (agitation, tremors, hyperthermia, tachycardia) if used with other serotonergic drugs
- Liver function tests (baseline and periodic)
薬物動態
吸収
Rapidly absorbed from both the GI tract and parenteral injection sites. Peak levels occur within 1-2 hours after oral dosing.
分布
Enters the CNS and maternal milk in levels equal to that found in maternal serum.
代謝
Metabolized in the liver to several metabolites, including the active metabolite desipramine.
過剰投与
Overdosage with tricyclics can be life-threatening, leading to severe arrhythmias and cardiorespiratory collapse. Because the toxicities and therapies for treatment are complicated and controversial, it is highly recommended to contact a poison control center for further information in any potential overdose situation.
製品
製剤
- Tablets
- Capsules
- Injection (Note: The injectable product is no longer marketed in the USA)
- 10 mg oral tablet
- 25 mg oral tablet
ヒト用医薬品
- Imipramine HCl Tablets: 10 mg, 25 mg & 50 mg (Tofranil, generic)
- Imipramine Pamoate Capsules: 75 mg, 100 mg, 125 mg & 150 mg (Tofranil-PM, generic)
- Tofranil 10 mg tablets
- Tofranil 25 mg tablets
- Imipramine 10 mg tablets
- Imipramine 25 mg tablets
規制ステータス
POM. Veterinary authorized products (e.g., clomipramine) are preferred under the cascade.
POM. Veterinary authorized products (e.g., clomipramine) are preferred under the cascade.
規制データなし: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
保管・安定性
Imipramine HCl tablets and pamoate capsules should be stored in tight, light-resistant containers, preferably at room temperature. The HCl injection should be stored at < 40°C; avoid freezing. Imipramine HCl will turn yellow to reddish on exposure. Slight discoloration will not affect potency, but marked changes in color are associated with a loss of potency.
飼主向け情報
- 忍耐が鍵：行動の変化が現れるまでに数週間かかる場合があります。処方通りに投薬を続け、獣医師に相談せずに急に投薬を中止しないでください。
- 安全第一：この薬は動物にも人間にも過剰摂取すると非常に毒性が高いです。子供が開けにくい容器に入れ、ペットや子供の手の届かない安全な場所に保管してください。
- 副作用：ペットが眠たそうにしたり、口が渇いたり、便秘になったりする場合があります。ペットが過度に興奮したり、震えたり、発作を起こした場合は、すぐに獣医師に連絡してください。
- 飲み忘れ：飲み忘れた場合は、気づいた時点で与えてください。ただし、絶対に2回分を一度に与えないでください。
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。