VetSheet

トラマドール

Tramadol

Tramadol hydrochloride

オピオイド様（μ受容体）作動薬 / 鎮痛薬POIVEpiduralSC犬猫馬

別名: Ultram ER · Ryzolt · Rybix ODT · Ultracet · Tralieve · Tramadol ER · Zamadol · CG-315E · tramadoli hydrochloridum · U-26225A · Tramadol hydrochloride

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

5 mg/kg PO q6-8h and up to 10 mg/kg PO q6-8hPO· q6-8h
— 🐕

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/Non-responsive pain5 mg/kg PO q6-8h and up to 10 mg/kg PO q6-8hPOq6-8h—🌎 NA
Analgesic2-5 mg/kg four times dailyPOq6h—🌎 NA
Chronic pain2-5 mg/kg PO 2-3 times a dayPOq8-12h—🌎 NA
Mild acute and chronic soft tissue and musculoskeletal pain2-5 mg/kgPOq8h—🌍 EU
Perioperative acute pain2 mg/kgIVsingle dose or as needed—🌍 EU
  • General/Non-responsive pain: Maximum analgesic effects may not occur immediately and may be delayed up to 14 days for chronic pain conditions.
  • Analgesic: Suggested starting dose.
  • Chronic pain: Reasonable for mild pain; adjust for severe pain. Best used as multimodal therapy with NSAIDs or other analgesics due to erratic pharmacokinetics.
  • Mild acute and chronic soft tissue and musculoskeletal pain: Chewable tablets are authorized for this use. Sustained-release tablets are unsuitable for once-daily dosing.
  • Perioperative acute pain: Used instead of traditional opioids to provide analgesia for acute pain.

猫

適応用量経路頻度期間地域
Starting dose2 mg/kg twice dailyPOq12h—🌎 NA
Current dosing recommendations1-2 mg/kg PO q12hPOq12h—🌎 NA
Chronic pain1-4 mg/kg PO 2-3 times a dayPOq8-12h—🌎 NA
Analgesia2-4 mg/kgPOq8h—🌍 EU
Analgesia1-2 mg/kgIVas needed—🌍 EU
Analgesia1-2 mg/kgSCas needed—🌍 EU
  • Starting dose: Based upon the pharmacokinetics of tramadol and ODT in cats.
  • Current dosing recommendations: Maximum analgesic effects may be delayed up to 14 days for chronic pain.
  • Chronic pain: Reasonable for mild pain; dose and interval may need adjustment for more severe pain.
  • Analgesia: Oral preparations are highly unpalatable to cats. Watch for dysphoria.

馬

適応用量経路頻度期間地域
Chronic laminitis pain5 mg/kg PO twice daily for seven days, alone or with ketamine at 0.6 mg/kg/hr IV during six hours each day for the first 3 days of treatmentPO/IVq12h7 days🌎 NA
  • Chronic laminitis pain: Pain relief was enhanced.

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。

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概要

トラマドールは、主に軽度から中等度の疼痛管理に使用され、時には鎮咳薬としても使用される、合成の中枢性​オピオイド様鎮痛薬​です。

​主な臨床的特徴：​

  • 弱い​μ-オピオイド受容体作動薬​として働き、​セロトニン​および​ノルアドレナリン​の再取り込みを阻害します。
  • 変形性関節症やがんなどの慢性疼痛に対する​マルチモーダル鎮痛プロトコル​（NSAIDs、ガバペンチン、アマンタジンなどとの併用）の一部として非常に有用です。
  • 慢性疼痛状態において、完全な鎮痛効果が得られるまでに最大​2週間​かかる場合があります。
  • ​臨床のポイント：​ モノグラフには米国では規制薬物ではないと記載されていますが、ヒトでの乱用の可能性があるため、​米国DEAは2014年にトラマドールをスケジュールIVの規制物質に再分類しました​。
  • 犬では一般的に忍容性が高く、鎮静が最も一般的な副作用です。猫では不快感（dysphoria）を経験することがあり、薬の嗜好性が非常に悪いです。

作用機序

Tramadol provides analgesia through a dual mechanism of action:

  1. ​Opioid Activity:​ Tramadol and its active metabolite ​O-desmethyltramadol (M1)​ bind to mu-opioid receptors in the central nervous system.
  2. ​Monoaminergic Activity:​ It inhibits the synaptic reuptake of ​serotonin (5-HT)​ and ​norepinephrine (NE)​ → enhancing descending inhibitory pathways of pain transmission in the spinal cord.

​Pharmacologic Pearl:​ The M1 metabolite is 6 times more potent as an analgesic and has 20 times greater affinity for mu-receptors than the parent drug. Dogs produce very little of the M1 metabolite compared to cats and humans, which explains why tramadol's opioid-mediated efficacy in dogs is often erratic and heavily reliant on its serotonin/norepinephrine reuptake inhibition. Naloxone only partially antagonizes tramadol's analgesic effects.

安全性・警告

禁忌

  • Hypersensitivity to tramadol or other opioids
  • Combination products containing acetaminophen (e.g., Ultracet) are STRICTLY CONTRAINDICATED in cats
  • Concurrent use with MAOIs (e.g., selegiline, amitraz) due to risk of serotonin syndrome
  • Patients with a history of epilepsy or seizure disorders

有害事象

  • Dogs: Excessive sedation, agitation, anxiety, tremor, dizziness
  • Dogs: Inappetence, vomiting, constipation, diarrhea
  • Cats: Dysphoria, mydriasis, dose avoidance (unpalatability)
  • Humans: Pruritus (approx. 10%)
  • Injectable form: Respiratory and cardiac depression
  • Sedation (especially at high doses in dogs)
  • Dysphoria (more likely in cats)
  • Nausea
  • Behavioral changes
  • Increased risk of seizures

注意事項

​Important Warnings:​

  • ​Seizure Risk:​ Use with caution in animals with preexisting seizure disorders or those receiving drugs that lower the seizure threshold. Tramadol has caused seizures in humans.
  • ​CNS/Respiratory Depression:​ Use cautiously with other CNS or respiratory depressants.
  • ​Geriatric/Debilitated Patients:​ Use with caution; dosage adjustments may be needed for patients with impaired renal or hepatic function.
  • ​Dependence & Withdrawal:​ Physical dependence can occur; withdraw gradually after chronic use.
  • ​Formulation Warning:​ Extended-release tablets must not be broken, crushed, or chewed, as this can lead to rapid absorption and toxicity. Dogs do not absorb ER tablets well.

医薬品相互作用

Digoxin

Rarely linked to digoxin toxicity in humans.

MAO Inhibitors (amitraz, selegiline)

Potential for fatal serotonin syndrome; concurrent use should be avoided.

Ondansetron

May reduce the effectiveness of both drugs.

Quinidine

May increase tramadol concentrations and decrease M1 (active metabolite) concentrations.

SAMe (S-adenosylmethionine)

Theoretically could cause additive serotonergic effects.

Sevoflurane

Pretreatment with tramadol reduced MAC values by approximately 30% in dogs and 40% in cats.

SSRI Antidepressants (fluoxetine, sertraline, paroxetine)

Can inhibit the metabolism of tramadol to its active metabolites, decreasing efficacy and increasing the risk of toxicity (serotonin syndrome, seizures).

Tricyclic Antidepressants (clomipramine, amitriptyline)

Increased risk for seizures; amitriptyline may inhibit tramadol metabolism.

Warfarin

Increased PT and INR reported in humans (relatively rare).

AmitriptylineMajor

Increased risk of serotonin syndrome

SelegilineMajor

Increased risk of serotonin syndrome

SSRIs (e.g., Fluoxetine)Major

Increased risk of serotonin syndrome

FentanylMajor

Increased risk of serotonin syndrome

PethidineMajor

Increased risk of serotonin syndrome

BuprenorphineMajor

Increased risk of serotonin syndrome

NSAIDs

Safe and synergistic multimodal analgesia

Gabapentin

Safe and synergistic multimodal analgesia

Amantadine

Safe and synergistic multimodal analgesia

監視

  • Clinical efficacy (pain scoring, mobility, comfort levels)
  • Adverse effects (excessive sedation, GI upset, dysphoria, agitation)
  • Pain scores to assess efficacy
  • Signs of sedation or dysphoria
  • Signs of serotonin syndrome (hyperthermia, hypertension, agitation, tremors)
  • Seizure activity in susceptible individuals

薬物動態

半減期

猫2.5 - 3.18 hours (parent); 4.5 - 4.8 hours (M1 metabolite)馬2-10 hours (adults); ~2 hours (foals); ~4 hours (M1 metabolite)犬1.7 hours (parent); ~2 hours (M1 metabolite)

吸収

Dogs: PO bioavailability ~65% (significant interpatient variability); Rectal ~10%. Cats: PO bioavailability ~60% (high interpatient variability). Horses: PO bioavailability ~14% (adults), 53% (neonatal foals), 20% (weaned foals).

分布

Dogs: Vd ~3.8 L/kg. Cats: Vd ~2 L/kg.

代謝

Extensively metabolized via several hepatic pathways. The active metabolite O-desmethyltramadol (M1) has potent agonist activity but is a minor metabolite in dogs. Cats produce more of the M1 metabolite.

消失

Dogs: Total body clearance ~55 mL/kg/min. Cats: Clearance ~12 mL/min/kg.

過剰投与

Acute oral overdoses may cause either CNS depressive signs or serotonin syndrome.

  • ​Clinical Signs:​ Lethargy, mydriasis, ataxia, and vomiting are most common. Stimulatory signs such as tachycardia, tremors, vocalization, agitation, and seizures may also occur. Cats frequently show mydriasis, hypersalivation, and tachycardia.
  • ​Treatment:​ Primarily supportive (maintaining respiration, treating seizures with benzodiazepines or barbiturates).

  • ​Important:​ Naloxone may NOT be useful in tramadol overdoses. It only partially reverses effects and may actually increase the risk of seizures. Cyproheptadine and phenothiazines can be used to treat stimulatory signs (serotonin syndrome).

製品

製剤

  • Oral tablets (immediate release)
  • Extended-release tablets
  • Oral disintegrating tablets
  • Injection (available commercially outside the USA)
  • 50 mg tablets
  • 100 mg, 200 mg, 300 mg immediate-release tablets
  • 20 mg, 80 mg chewable tablets (veterinary)
  • 10 mg, 25 mg tablets
  • Sustained-release tablets (various sizes)
  • 5 mg/ml oral liquid
  • 50 mg/ml injectable solution

動物用医薬品

  • None commercially available in the USA.
  • Tralieve 20 mg, 80 mg chewable tablets
  • Zamadol

ヒト用医薬品

  • Tramadol HCl Oral Tablets (film-coated) 50 mg (Ultram, generic)
  • Tramadol HCl Extended-Release Tablets 100 mg, 200 mg, 300 mg (Ultram ER, Ryzolt, generic)
  • Tramadol HCl Oral Disintegrating Tablets 50 mg (Rybix ODT)
  • Tramadol HCl 37.5 mg / Acetaminophen 325 mg tablets (Ultracet) - WARNING: DO NOT USE IN CATS
  • Tramadol ER
  • 50 mg immediate-release tablets

規制ステータス

European Union✓ 承認済み処方箋医薬品EMA
🐕 Dogs

Authorized veterinary chewable tablets available for dogs.

United Kingdom✓ 承認済み処方箋医薬品 · Schedule 3 CDVMD
🐕 Dogs

POM-V, POM CD Schedule 3. Subject to safe custody requirements.

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

保管・安定性

Store tablets at room temperature 25°C (77°F); excursions permitted to 15-30°C (59-86°F). Dispense in tight, light-resistant containers.

飼主向け情報

飼い主様へ：

  • ​投与方法：​ 食事と一緒でも、空腹時でも投与できます。空腹時に薬を飲んで嘔吐した場合は、次回から少量のおやつや食事と一緒に与えてみてください。
  • ​味：​ この薬は非常に苦味があります。特に猫は、過剰によだれを垂らしたり、薬を飲むのを嫌がったりすることがあります。徐放錠を砕いたり割ったりしないでください。
  • ​行動の変化：​ 覚醒状態に変化が生じる可能性があります。ペットが異常に眠そうにしたり、逆に不安そうにしたり、落ち着きがなくなったり、よく鳴くようになったりする（特に猫）ことがあります。これらの症状がひどい場合は、獣医師にご相談ください。
  • ​忍耐が必要です：​ 関節炎などの慢性疾患の場合、完全な鎮痛効果が見られるまでに最大2週間の継続的な投与が必要になることがあります。
  • ​安全上の警告：​ お子様や他のペットの手の届かないところに保管してください。トラマドールとアセトアミノフェン（Ultracetなど）が配合された人間用の薬は、アセトアミノフェンが猫にとって非常に有毒であり、多くの場合致命的となるため、​絶対に​ペット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。