クロニジン
Clonidine
Clonidine hydrochloride (imidazoline derivative)
別名: Duraclon · Jenloga · Catapres-TTS · ST-155 · clonidini hydrochloridum · Adesipress-TTS · Arkamin · Aruclonin · Atensina · Barclyd · Cantanidin · Caprysin · Catanidin · Catapresan · Catapressan · Clonistada · Clonnirit · Dispaclonidin · Dixarit · Epiclodina · Glausine · Haemiton · Menograine · Mirfat · Normopresan · Paracefan · Tenso-Timelets · Clonidina · Clonidine hydrochloride · Clonidinum
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
構造化された用量計算エビデンスAdjunctive antidiarrheal therapy for refractory cases of inflammatory bowel disease (extra-label)
認証済み獣医師の確認が必要
- q8-12h
NA
必ず考慮する臨床コンテキスト (2)
- ■ This medicine may be given with or without food. If your animal vomits or acts sick after receiving this medicine on an empty stomach, try giving the next dose with food or a small treat. If vomiting continues, contact your veterinarian.
- Clonidine tablets should be stored in tight, light-resistant containers at room temperature, 25°C (77°F); excursions from 15°C to 30°C (59°F-86°F) are permitted. The preservative-free injection for epidural use should be stored at controlled room temperature, 20°C to 25°C (68°F-77°F). Because it contains no preservative, unused portions of the injection should be discarded.
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
クロニジンは中枢性α2アドレナリン受容体作動薬であり、獣医学においては伝統的に犬の成長ホルモン（GH）欠乏症や褐色細胞腫の診断薬として使用されています。また、難治性の炎症性腸疾患（IBD）（特に猫）の補助治療や、重度の疼痛または外科麻酔のための硬膜外補助薬としても機能します。
臨床のポイント（薬理学的補足）：
- モノグラフでは診断および胃腸への用途が強調されていますが、現代の獣医行動医学において、クロニジンは犬の恐怖性不安、音響恐怖症、状況的パニックを管理するための適応外使用が増加しています。
- 交感神経の覚醒を抑えることで抗不安作用と鎮静作用を提供し、他の鎮静剤で見られるような重度の運動失調を伴わないことが多いです。
- 心血管系への影響があるため、患者の慎重な選択と用量調整が必要です。
作用機序
Clonidine acts centrally at the brain stem, stimulating alpha-2 adrenoreceptors.
- Cardiovascular/Sympathetic: Stimulation of presynaptic alpha-2 receptors (e.g., in the locus coeruleus) → decreases norepinephrine release → reduces sympathetic outflow from the CNS → decreased peripheral resistance, heart rate, and blood pressure.
- Endocrine: Stimulates GHRH (Growth Hormone Releasing Hormone) → transient release of Growth Hormone (GH).
- Analgesia: Stimulates presynaptic and postjunctional alpha-2 adrenoreceptors in the dorsal horn of the spinal cord → blocks pain signal transmission to the brain.
- Gastrointestinal: Alpha-2 stimulation alters enteric nervous system tone, increasing fluid absorption and decreasing motility, aiding in refractory IBD.
安全性・警告
禁忌
- Known hypersensitivity to clonidine
- Severe cardiovascular disease (use with extreme caution)
- Renal disease (use with extreme caution)
有害事象
- Transient hyperglycemia
- Dry mouth
- Constipation
- Aggressive behavior
- Hypotension
- Collapse
- Bradycardia
- Transient sedation
- Rebound hypertension (if withdrawn abruptly)
注意事項
Clonidine has a narrow margin of safety. It should be used with caution in patients with severe cardiovascular disease, including conduction disturbances or heart failure. Use very cautiously in patients with renal failure. Abrupt withdrawal, especially when used with beta-blockers, may cause rebound hypertension.
医薬品相互作用
Possible additive hypotensive effects
May enhance bradycardia. If discontinuing, beta-blocker should be stopped first, then clonidine tapered to avoid rebound hypertension.
May exacerbate the actions of other CNS depressant drugs
Possible additive bradycardia
May decrease the antihypertensive effects of clonidine
May block the antihypertensive effects of clonidine
Increased central nervous system depression and hypotension
Additive sedation, bradycardia, and respiratory depression
Additive hypotensive and bradycardic effects; may exacerbate rebound hypertension upon withdrawal
Additive lowering of blood pressure
監視
- Growth Hormone (GH) levels and adverse effects (when used for diagnostics)
- Blood pressure
- Heart rate
- Efficacy and adverse effect profile (when used for ongoing diarrhea treatment)
- Degree of sedation
- Behavioral response
- Plasma IGF-1 or GH levels (when used diagnostically)
薬物動態
半減期
吸収
Well absorbed after oral administration in humans (peak plasma 3-5 hours). After epidural administration, maximal analgesia occurs within 30-60 minutes.
分布
Widely distributed into body tissues; tissue concentrations are higher than in plasma. Enters the CSF, but brain concentrations are low compared with other tissues. In cats, exhibits a two-compartment open model and penetrates tissues rapidly.
代謝
Metabolized in the liver; one active metabolite (p-hydroxyclonidine) has been identified.
消失
Up to 60% of a dose is eliminated unchanged in the urine. Elimination may be prolonged with higher dosages (dose-dependent elimination kinetics) or in renal dysfunction.
過剰投与
Clonidine has a narrow margin of safety.
- Clinical Signs: Hypotension, bradycardia, vomiting, weakness, depression, lethargy, tachycardia, ataxia, and hypertension. Rarely, seizures or respiratory depression.
- Toxicity Values: LD50 for oral clonidine in rats is 465 mg/kg; mice 206 mg/kg.
- Treatment: For large overdoses, gut evacuation using standard protocols (use emetics cautiously as consciousness may deteriorate rapidly). Symptomatic and supportive care. Fluids and pressors (e.g., dopamine) for hypotension. IV atropine for bradycardia. Atipamezole or yohimbine may be used to reverse cardiovascular effects, but multiple doses may be required as signs can last up to 48 hours.
製品
製剤
- Epidural injection
- Oral tablets
- Oral modified-release tablets
- Transdermal patch
- Injectable: 150 μg/ml solution
- Oral: 25 μg tablets
ヒト用医薬品
- Clonidine HCl Injection for epidural use: 100 micrograms/mL & 500 micrograms/mL preservative-free (Duraclon)
- Clonidine HCl Oral Tablets: 0.1 mg, 0.2 mg & 0.3 mg (Catapres, generic)
- Clonidine HCl Oral Modified-release Tablets: 0.1 mg (Jenloga)
- Clonidine HCl Transdermal: 0.1 mg/24hrs, 0.2 mg/24hrs, & 0.3 mg/24hrs (Catapres-TTS-1, 2, or 3)
- Catapres 150 μg/ml injectable solution
- Catapres 25 μg oral tablets
規制ステータス
POM (Prescription Only Medicine)
POM-V
規制データなし: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
保管・安定性
Tablets should be stored in tight, light-resistant containers at room temperature (15-30°C / 59-86°F). Preservative-free injection for epidural use should be stored at controlled room temperature (25°C); unused portions must be discarded.
飼主向け情報
目的： 獣医師は、重度の下痢、疼痛管理、または重度の不安や恐怖症に対する適応外使用など、ペットの症状を管理するためにクロニジンを処方しました。
- 厳格な投薬： クロニジンは安全域が狭い薬です。処方された正確な用量を与えてください。指示された以上の量を絶対に与えないでください。
- 副作用： 極度の無気力、脱力感、歯茎の蒼白、または予期しない行動の変化（攻撃性など）の兆候に注意してください。これらが発生した場合は獣医師に連絡してください。
- 急に中止しないでください： 獣医師に相談せずにこの薬を突然中止しないでください。血圧の危険な急上昇（リバウンド高血圧）を引き起こす可能性があります。
- 誤飲： すべてのペットや子供の手の届かないところに保管してください。過剰摂取が発生した場合は、直ちに緊急の獣医治療を受けてください。
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