メチルフェニデート
Methylphenidate
Methylphenidate Hydrochloride
別名: Concerta · Metadate · Methylin · Daytrana · Focalin · Equasym · Attenta · Rilatine · Riphenidate · Ritalina · Ritaline · Ritaphen · Rubifen · Tranquilyn
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 narcolepsy/cataplexy | 5-10 mg (total dose) | PO | once daily | — | 🌎 NA |
| Treatment of narcolepsy/cataplexy (to supplement imipramine) | 0.25-0.5 mg/kg or 5-10 mg (total dose) | PO | q12-24h | — | 🌎 NA |
| Diagnosis and treatment of hyperkinesis | 5-20 mg (total dose) | PO | q8-12h | 3 days | 🌎 NA |
| Hyperkinesis-hyperactivity | Small dogs: 5+ mg total dose; Large Dogs: 20-40 mg total dose | PO | q12h | — | 🌎 NA |
- Treatment of narcolepsy/cataplexy (to supplement imipramine): Used to supplement imipramine given at 0.5-1 mg/kg PO q8-12h
- Diagnosis and treatment of hyperkinesis: Give for 3 days and assess for improvement of target behaviors (anxiety, overactivity, learning ability)
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
メチルフェニデートは、構造および薬理学的にアンフェタミンに関連する中枢神経系（CNS）刺激薬です。獣医学においては、主に犬のナルコレプシー/カタプレキシーおよび運動亢進症（多動症）の診断および管理のために適応外使用されます。
中枢神経への作用に加えて、弱い交感神経模倣作用を持ちますが、標準的な治療用量では末梢循環への影響は最小限です。
臨床上の注意点：メチルフェニデートは米国においてスケジュールII（C-II）の規制薬物であり、厳格な処方規制と人間による乱用の高いリスクを伴います。獣医師は処方および調剤の際、適切な法的および倫理的予防措置を講じる必要があります。
作用機序
Methylphenidate acts primarily as a norepinephrine-dopamine reuptake inhibitor (NDRI).
- It binds to and blocks the dopamine transporter (DAT) and norepinephrine transporter (NET) on presynaptic neurons.
- Blockade of these transporters → prevents the reuptake of monoamines → increases the concentration of dopamine and norepinephrine in the extraneuronal space (synaptic cleft).
- This amplified monoamine signaling in the brainstem arousal system and cerebral cortex leads to increased alertness, focus, and CNS stimulation.
安全性・警告
禁忌
- Seizure disorders
- Cardiac disease or hypertension
- Aggressive animals
有害事象
- Tachycardia (increased heart rate)
- Tachypnea (increased respiratory rate)
- Anorexia
- Tremors
- Hyperthermia (particularly exercise-induced)
注意事項
Use with extreme caution in dogs with pre-existing seizure disorders, cardiac disease, hypertension, or those exhibiting aggressive behavior. Methylphenidate is a Class-II controlled substance with a high potential for human abuse; prescribe and dispense with strict adherence to controlled substance regulations.
医薬品相互作用
Methylphenidate may increase serum levels of these anticonvulsants
Rare cases of cardiovascular effects (including death) reported in humans; mechanism unknown
Methylphenidate may reduce the efficacy of hypotensive effects
Concurrent use could lead to a severe hypertensive crisis
Methylphenidate may inhibit SSRI metabolism and increase their serum levels
Methylphenidate may inhibit TCA metabolism and increase their serum levels
Methylphenidate may inhibit warfarin metabolism and increase INR
監視
- Clinical efficacy (improvement in target behaviors or narcoleptic episodes)
- Vital signs (heart rate, respiratory rate)
- Body weight (monitor for anorexia/weight loss)
- Periodic CBC with differential and platelet counts (recommended during prolonged therapy based on human guidelines)
薬物動態
半減期
吸収
Dogs: Immediate-release tablets peak in ~15 minutes. Sustained-release tablets peak in ~30 minutes but with much lower peak concentrations. Humans: Rapidly and well absorbed from the GI tract; food may increase the rate but not the extent of absorption. Peak levels occur ~2 hours post-dose.
分布
Humans: Protein binding is low.
代謝
Humans: Extensively metabolized during the first-pass effect.
消失
Humans: Less than 1% is excreted unchanged in the urine. Clearance in dogs is rapid (0.27 L/hr for IR, 0.97 L/hr for SR).
過剰投与
Toxicity can occur at relatively low doses in veterinary patients.
- Dogs: Doses of 1 mg/kg (or below) can cause toxic reactions. One fatality was reported at 3.1 mg/kg, though research dogs have survived 20 mg/kg/day for 90 days.
- Cats: A 5 mg tablet caused severe toxicity (tremors, agitation, mydriasis, tachycardia, tachypnea, hypertension) which resolved after 25 hours with supportive care.
Clinical Signs of Overdose: Primarily CNS over-stimulation and excessive sympathomimetic effects: hyperactivity, salivation, diarrhea, head bobbing, agitation, tachycardia, hypertension, tremors, seizures, and hyperthermia.
Treatment:
- Decontamination: Standard gut detoxification (emesis, activated charcoal, cathartic). Avoid emesis if the animal is already symptomatic due to seizure/aspiration risks.
- Supportive Care:
- Phenothiazines (e.g., acepromazine, chlorpromazine) to control agitation.
- Beta-blockers to manage severe tachycardia.
- External cooling for hyperthermia.
- Cyproheptadine may be administered to help prevent or treat serotonin syndrome.
製品
製剤
- Oral tablets
- Chewable tablets
- Extended-release tablets
- Extended-release capsules
- Oral solution
- Transdermal patch
ヒト用医薬品
- Methylphenidate Oral Tablets: 5 mg, 10 mg & 20 mg
- Chewable Tablets: 2.5 mg, 5 mg & 10 mg
- Extended-Release Tablets: 10 mg, 18 mg, 20 mg, 27 mg, 36 mg & 54 mg
- Extended-Release Capsules: 20 mg, 30 mg, 40 mg, 50 mg & 60 mg
- Methylphenidate Oral Solution: 5 mg/5 mL & 10 mg/5 mL
- Methylphenidate Transdermal Patch: 10 mg/9 h, 15 mg/9 h, 20 mg/9 h & 30 mg/9 h
規制ステータス
規制データなし: 🇺🇸 US · 🇪🇺 EU · 🇬🇧 UK · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
保管・安定性
Unless otherwise noted on the label, methylphenidate tablets and extended-release tablets/capsules should be stored in tight, light-resistant containers at room temperature.
飼主向け情報
- 安全な保管：この薬は人間による乱用の可能性が高い規制薬物です。鍵のかかるキャビネットや安全な場所に厳重に保管してください。
- 投与方法：ペットに徐放性（効果が長続きする）の錠剤やカプセルが処方された場合、砕いたり噛ませたりしないでください。必ずそのままの形で与えてください。
- 観察：心拍数の増加、呼吸の乱れ、落ち着きのなさ、震え、食欲不振など、過剰な刺激の兆候がないかペットを注意深く観察してください。これらの兆候が見られた場合は、直ちに獣医師に報告してください。
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。