フェンタニル
Fentanyl
Fentanyl citrate
別名: Sublimaze · Duragesic · Actiq · Fentora · Ionsys · Fentadon · Durogesic · Fentanyl citrate · fentanylum · fentanyli citras · phentanyl citrate · McN-JR-4263-49 · Fentanil
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 |
|---|---|---|---|---|---|
| Perioperative pain | The combination of a 10 micro-grams/kg loading dose IV followed by a CRI of 10 micrograms/kg/hour | IV/CRI | Continuous | Perioperative | 🌎 NA |
| Pain management | 2-5 micrograms/kg IV, followed by a CRI at 2-5 micrograms/kg/hr | IV/CRI | Continuous | — | 🌎 NA |
| Surgical analgesia | CRI at 10-45 micrograms/kg/hr | CRI | Continuous | Intraoperative | 🌎 NA |
| Analgesia | 2-6 micrograms/kg/hour | CRI | Continuous | — | 🌎 NA |
| Induction | 0.001-0.005 mg/kg IV | IV | Single dose | — | 🌎 NA |
| MAC reduction during general anesthesia | 10-45 micrograms/kg/hr CRI | CRI | Continuous | Intraoperative | 🌎 NA |
| Severe to excruciating pain in the emergent patient | Fentanyl at 1050 micrograms/kg, administered IV titrated to effect; use the effective dose as an hourly CRI. | IV/CRI | Titrated to effect | — | 🌎 NA |
| Epidural for pain control | 0.004 mg/kg (4 micrograms/kg), diluted with 0.2 mL with preservative-free saline or local anesthetic. | Epidural | Single dose | 1/2 hour | 🌎 NA |
| Transdermal Analgesia (<5kg) | 25 mcg/hr or 12.5 mcg/hr | Transdermal | q72h | — | 🌎 NA |
| Transdermal Analgesia (5-10 kg) | 25 mcg/hr | Transdermal | q72h | — | 🌎 NA |
| Transdermal Analgesia (10-20 kg) | 50 mcg/hr | Transdermal | q72h | — | 🌎 NA |
| Transdermal Analgesia (20-30 kg) | 75 mcg/hr | Transdermal | q72h | — | 🌎 NA |
| Transdermal Analgesia (>30 kg) | 100 mcg/hr | Transdermal | q72h | — | 🌎 NA |
| Intraoperative analgesia | Intermittent bolus doses or continuous rate infusion (exact dose not specified) | IV | Intermittent or CRI | Intraoperative | 🌍 EU |
| Postoperative analgesia | Low end of the dose range by continuous rate infusion | IV | CRI | Postoperative | 🌍 EU |
| Postoperative or chronic pain | Transdermal patch (size based on patient requirement) | Topical | Apply 24 hours before surgery | Up to 72 hours | 🌍 EU |
- Perioperative pain: Guideline for CRI during general anesthesia
- Pain management: Loading dose followed by CRI
- Severe to excruciating pain in the emergent patient: Note: '1050' appears exactly as written in source text, likely a typo for 10-50. May combine with ketamine and lidocaine.
- Epidural for pain control: Onset in less than 10 minutes
- Transdermal Analgesia (<5kg): Apply 12-24 hours prior to need. Half-patch dosing may be desired for very small dogs.
- Transdermal Analgesia (5-10 kg): Apply 12-24 hours prior to need.
- Transdermal Analgesia (10-20 kg): Apply 12-24 hours prior to need.
- Transdermal Analgesia (20-30 kg): Apply 12-24 hours prior to need.
- Transdermal Analgesia (>30 kg): Apply 12-24 hours prior to need.
- Intraoperative analgesia: Give slowly to avoid severe bradycardia/asystole.
- Postoperative analgesia: Monitor respiratory function closely.
- Postoperative or chronic pain: Takes ~24 hours to attain adequate plasma concentrations. Use as an adjunctive analgesic.
猫
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Perioperative pain | 2-3 micrograms/kg IV plus 2-3 micrograms/kg/hour IV infusion | IV/CRI | Continuous | Perioperative | 🌎 NA |
| Pain management | 1-3 micrograms/kg IV, followed by a CRI at 1-4 micrograms/kg/hr | IV/CRI | Continuous | — | 🌎 NA |
| Surgical analgesia | CRI at 10-30 micrograms/kg/hr | CRI | Continuous | Intraoperative | 🌎 NA |
| Analgesia | 2-4 micrograms/kg/hour | CRI | Continuous | — | 🌎 NA |
| Induction | 0.001-0.002 mg/kg IV | IV | Single dose | — | 🌎 NA |
| MAC reduction during general anesthesia | 10-20 micrograms/kg/hr CRI | CRI | Continuous | Intraoperative | 🌎 NA |
| Severe to excruciating pain in the emergent patient | Fentanyl at 1050 micrograms/kg, administered IV titrated to effect; use the effective dose as an hourly CRI. | IV/CRI | Titrated to effect | — | 🌎 NA |
| Epidural for pain control | 0.004 mg/kg (4 micrograms/kg), diluted 0.2 mL with preservative-free saline or local anesthetic. | Epidural | Single dose | 1/2 hour | 🌎 NA |
| Maintenance analgesia/heavy sedation in critically ill hypotensive animals | fentanyl at 0.5-0.8 micrograms/kg/minute (equivalent to 30-50 micrograms/kg/hr). | CRI | Continuous | — | 🌎 NA |
| Transdermal Analgesia | 25 mcg/hr or 12.5 mcg/hr | Transdermal | q120h | Up to 5 days | 🌎 NA |
| Intraoperative analgesia | Intermittent bolus doses or continuous rate infusion (exact dose not specified) | IV | Intermittent or CRI | Intraoperative | 🌍 EU |
| Postoperative analgesia | Low end of the dose range by continuous rate infusion | IV | CRI | Postoperative | 🌍 EU |
| Postoperative or chronic pain | Transdermal patch (size based on patient requirement) | Topical | Apply 7 hours before surgery | Up to 72 hours | 🌍 EU |
- Pain management: Loading dose followed by CRI
- Severe to excruciating pain in the emergent patient: Note: '1050' appears exactly as written in source text, likely a typo for 10-50.
- Epidural for pain control: Onset in less than 10 minutes
- Maintenance analgesia/heavy sedation in critically ill hypotensive animals: Used in addition to a local line block. May combine with midazolam.
- Transdermal Analgesia: Apply 6-24 hours prior to need. 12 mg patches are available for very small cats.
- Intraoperative analgesia: Give slowly to avoid severe bradycardia/asystole.
- Postoperative analgesia: Monitor respiratory function closely.
- Postoperative or chronic pain: Takes ~7 hours to attain adequate plasma concentrations. Use as an adjunctive analgesic.
小型哺乳類
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Perioperative pain (Rabbits/Rodents/Small Mammals) | 5-20 micrograms/kg IV bolus | IV | Single dose | 30-60 minute duration | 🌎 NA |
| Postoperative analgesia (Rabbits) | 1/2 small patch (25 micrograms/hr) per medium sized rabbit (3 kg) every 3 days. Do not cut patch | Transdermal | q72h | — | 🌎 NA |
- Perioperative pain (Rabbits/Rodents/Small Mammals): Causes sedation and respiratory depression
フェレット
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Pre-op dose | 5-10 micrograms/kg IV | IV | Single dose | Pre-op | 🌎 NA |
| Intra-operatively | CRI at 10-20 micrograms/kg/hr with a ketamine CRI (0.3-0.4 mg/kg/hr) | CRI | Continuous | Intraoperative | 🌎 NA |
| Postoperatively | 2-5 micrograms/kg/hr with a ketamine CRI. | CRI | Continuous | Postoperative | 🌎 NA |
馬
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Transdermal Analgesia (350-500 kg) | 100 mcg/hr | Transdermal | q48h | — | 🌎 NA |
- Transdermal Analgesia (350-500 kg): Apply 6+ hours prior to need. ARCI UCGFS Class 1 Drug.
豚
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Transdermal Analgesia (17-25 kg) | 50 mcg/hr | Transdermal | — | — | 🌎 NA |
羊
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Transdermal Analgesia | 25 mcg/hr | Transdermal | — | — | 🌎 NA |
ヤギ
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Transdermal Analgesia | 25 mcg/hr | Transdermal | — | — | 🌎 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
フェンタニルは、非常に強力な合成フェニルピペリジン誘導体であり、獣医学において中等度から重度の疼痛管理に広く使用されるクラスIIオピオイド鎮痛薬です。
主な薬理学的特徴：
- 効力： モルヒネの約75〜100倍の効力があります。
- 脂溶性： フェンタニルは非常に高い脂溶性を持ち、血液脳関門を迅速に通過します（静脈内投与時の効果発現が非常に速い）。この特性により、経皮投与（パッチ）に非常に適しています。
- 持続時間： 単回静脈内投与の場合、脳から他の組織への迅速な再分布のため、効果の持続時間は非常に短いです（15〜30分）。したがって、持続的な鎮痛のためには、持続静注（CRI）または経皮パッチによる投与が最も一般的です。
臨床応用：
- 術後疼痛の補助的コントロール。
- 重度の慢性痛、鈍痛、または非特異的な広範な疼痛（例：がん、膵炎、大動脈血栓塞栓症）の管理。
- 周術期に使用し、吸入麻酔薬の最小肺胞濃度（MAC）を大幅に低下させ、心機能が低下した患者の心血管系の安定性を提供します。
臨床のポイント： 経皮パッチは非常に便利ですが、個体間の吸収のばらつきが非常に大きいです。フェンタニルパッチに依存する場合は、常に「レスキュー」用の注射用鎮痛薬を用意しておく必要があります。
作用機序
Fentanyl is a highly selective full agonist at the mu-opioid receptor (MOR).
Mechanism Pathway:
- Receptor Binding: Fentanyl binds to presynaptic and postsynaptic mu-receptors primarily located in the central nervous system (limbic system, spinal cord, thalamus, midbrain) and peripheral tissues.
- G-Protein Activation: Binding activates inhibitory G-proteins (Gi/Go).
- Cellular Effects:
- Inhibits adenylate cyclase, decreasing intracellular cAMP.
- Promotes the opening of inward-rectifying potassium (K+) channels, leading to neuronal hyperpolarization.
- Inhibits the opening of voltage-gated calcium (Ca2+) channels on presynaptic nerve terminals.
- Analgesia: This cascade profoundly inhibits the release of excitatory, nociceptive neurotransmitters (such as Substance P and glutamate) and decreases the excitability of postsynaptic neurons, effectively blocking pain transmission.
安全性・警告
禁忌
- Known hypersensitivity to fentanyl or patch adhesive
- Conditions where additional respiratory or CNS depression would be deleterious
- No specific contraindications available in the monograph (use with caution in patients with respiratory compromise)
有害事象
- Dose-related respiratory depression
- CNS depression (sedation)
- Circulatory depression (bradycardia)
- Dysphoria or agitation (especially in cats)
- Urine retention
- Constipation
- Contact dermatitis/rash at patch site
- Altered thermoregulation (hypothermia or hyperthermia)
- Severe bradycardia
- Asystole (with rapid IV injection)
- Reduction in heart rate
注意事項
Patient Selection: Use with extreme caution in geriatric, severely ill, or debilitated patients, and those with preexisting respiratory compromise.
Transdermal Patch Warnings:
- Heat Exposure: Do NOT allow the applied patch to be exposed to exogenous heat sources (e.g., heating pads, heated cages, direct sunlight). Heat significantly increases drug release and absorption, which has resulted in fatal overdoses.
- Fever: Febrile patients may have increased absorption of fentanyl and require intense monitoring. Consider removing the patch if a fever develops.
- Patch Integrity: Do NOT cut patches unless specifically advised by a pharmacist (cutting alters the drug-releasing membrane of gel-reservoir patches, leading to rapid, uncontrolled drug release).
- Variable Absorption: Absorption is highly variable. Always have injectable rescue analgesia available.
Feline Specifics: Opioids may cause mydriasis (dilated pupils) in cats. Approach slowly to avoid startling them, and keep them out of bright light.
Laboratory Alterations: Opiates can increase biliary tract pressure, potentially elevating plasma amylase and lipase values for up to 24 hours post-administration.
医薬品相互作用
May inhibit fentanyl metabolism, increasing risk of toxicity
Additive CNS and respiratory depressant effects
Opiates may decrease diuretic efficacy in congestive heart failure patients
May inhibit fentanyl metabolism
Severe and unpredictable opiate potentiation; generally not recommended within 14 days of MAOI use
Fentanyl may enhance neuromuscular blockade
High fentanyl doses combined with nitrous oxide may cause cardiovascular depression
May increase the metabolism of fentanyl, reducing its efficacy
May increase the metabolism of fentanyl
Fentanyl may exacerbate the effects of tricyclic antidepressants
Opiates may potentiate anticoagulant activity
Reduces the dose requirement for other anaesthetic agents
監視
- Analgesic efficacy (pain scoring)
- Heart rate (monitor for bradycardia)
- Respiratory rate and depth
- Body temperature (monitor for fever which increases patch absorption)
- Neurologic status (sedation, dysphoria)
- Heart rate and rhythm (monitor for bradycardia)
- Blood pressure
- Adequacy of analgesia
- Body temperature (avoid external heat on patches)
薬物動態
半減期
吸収
Transdermal absorption is highly variable among patients. Cats tend to achieve therapeutic levels faster than dogs. Dogs require patch application 12-24 hours in advance; cats 6-24 hours; horses ~6 hours. Febrile patients may have significantly increased absorption.
分布
Rapidly distributes due to high lipophilicity. Exhibits a large volume of distribution (5 L/kg in dogs).
代謝
Hepatic metabolism (implied by interactions with CYP inhibitors like azole antifungals and macrolides).
消失
Total clearance in dogs is 78 mL/min/kg.
過剰投与
Clinical Signs of Overdose: Profound respiratory and/or CNS depression, cardiovascular collapse, bradycardia, hypothermia, tremors, neck rigidity, and seizures. Newborns are particularly susceptible.
Treatment:
- Naloxone is the specific reversal agent of choice for treating respiratory depression.
- Because naloxone's duration of action is often shorter than fentanyl's, repeated doses or a CRI of naloxone may be required.
- Patients must be closely monitored for re-narcotization.
- Mechanical respiratory support should be instituted in cases of severe respiratory depression.
製品
製剤
- Injectable solution (0.05 mg/mL)
- Transdermal patch (12, 25, 50, 75, 100 mcg/hr)
- Buccal tablets
- Transmucosal lozenges
- Iontophoretic transdermal system
- Oral tablets: 100 μg, 200 μg, 400 μg, 600 μg, 800 μg
- Injectable solution: 50 μg/ml
- Transdermal patches: 12.5 μg/h, 25 μg/h, 50 μg/h, 75 μg/h, 100 μg/h
動物用医薬品
- None (No veterinary-labeled products available)
- Fentadon 50 μg/ml solution
ヒト用医薬品
- Fentanyl Buccal Tablets: 100 mcg, 200 mcg, 400 mcg, 600 mcg, & 800 mcg (Fentora)
- Fentanyl Injectable: 0.05 mg/mL (50 mcg/mL) in various ampules and vials (Sublimaze)
- Fentanyl Transdermal System: 12 mcg/hr, 25 mcg/hr, 50 mcg/hr, 75 mcg/hr, 100 mcg/hr (Duragesic)
- Fentanyl Iontophoretic Transdermal System: 40 mcg/dose (Ionsys)
- Fentanyl Transmucosal System (Lozenges): 200 mcg to 1600 mcg (Actiq)
- Durogesic patches
- Fentanyl patches/tablets
- Fentora tablets
- Sublimaze solution
規制ステータス
POM-V CD SCHEDULE 2
POM-V CD SCHEDULE 2, POM CD SCHEDULE 2
規制データなし: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
保管・安定性
Transdermal patches: Store below 25°C (77°F). Apply immediately after removing from the sealed package. Do not cut patches. Buccal tablets: Store at room temperature; do not refrigerate or freeze. Injectable: Protect from light; it is hydrolyzed in acidic solutions.
飼主向け情報
飼い主様向けの重要な安全情報：
- 子供やペットに対する極度の危険性： フェンタニルは非常に強力な麻薬性鎮痛薬です。パッチが剥がれたり、ペットが外したりした場合、子供や他の動物が噛んだり飲み込んだりすると致命的になる可能性があります。使用済みのパッチは安全に廃棄してください（例：粘着面を内側にして半分に折り、トイレに流すか、動物病院に返却する）。
- 人への誤接触： 誤ってパッチの粘着面やゲルに触れてしまった場合は、すぐに水だけで手を洗ってください。石鹸、アルコール、手指消毒剤は絶対に使用しないでください。これらは皮膚からの薬の吸収を増加させる可能性があります。
- 熱源の厳禁： パッチを貼っている間は、ペットをペット用ヒーター、電気毛布の上に乗せたり、強い直射日光に当てたりしないでください。熱により薬が急速に放出され、致命的な過剰投与を引き起こす可能性があります。
- 効果発現の遅れ： パッチが効き始めるまでには時間がかかります（犬で12〜24時間、猫で6〜12時間）。獣医師はこの空白期間を埋めるために他の痛み止めを処方することがあります。
- 観察： ペットに極度の無気力、呼吸の深刻な変化（非常に遅い、または浅い）、異常な興奮が見られないか注意深く観察してください。これらの症状が現れた場合は、直ちに獣医師に連絡してください。
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。