アミノフィリン / テオフィリン
Aminophylline / Theophylline
1,3-dimethyl-7H-purine-2,6-dione (Theophylline); Theophylline ethylenediamine (Aminophylline)
別名: Theochron · Theo-Cap · Theo-24 · Uniphyl · Bronkodyl · Elixophyllin · Theo-Dur · Slo-Bid · aminofilina · aminophyllinum · euphyllinum · metaphyllin · theophylline and ethylenediamine · theophylline ethylenediamine compound · theophyllinum ethylenediaminum · anhydrous theophylline · teofillina
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 |
|---|---|---|---|---|---|
| Bronchodilation (Extended-Release) | 10 mg/kg PO every 12 hours initially, if no adverse effects are observed and the desired clinical effect is not achieved, give 15 mg/kg PO q12h | PO | q12h | — | 🌎 NA |
| Tracheal collapse (mild clinical signs, <50% collapse) | 11 mg/kg PO, IM or IV three times daily. | PO/IM/IV | q8h | — | 🌎 NA |
| Severe, acute pulmonary edema and bronchoconstriction | Aminophylline 4-8 mg/kg IV or IM, or 6-10 mg/kg PO every 8 hours. | IV/IM/PO | q8h | — | 🌎 NA |
| Cough | Aminophylline: 10 mg/kg PO, IV three times daily | PO/IV | q8h | — | 🌎 NA |
| Collapsing trachea (bronchodilator) | 11 mg/kg PO or IV q6-12h | PO/IV | q6-12h | — | 🌎 NA |
- Bronchodilation (Extended-Release): Using Theochron Extended-Release Tablets or Theo-Cap Extended-Release Capsules
- Tracheal collapse (mild clinical signs, <50% collapse): Aminophylline
- Severe, acute pulmonary edema and bronchoconstriction: Long-term use is not recommended.
猫
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Bronchodilation (Extended-Release) | 20 mg/kg PO once daily in the PM; using Slo-Bid: 25 mg/kg PO once daily in the PM | PO | q24h | — | 🌎 NA |
| Bronchodilation | 6.6. mg/kg PO twice daily; using sustained release tablets (Theo-Dur): 25-50 mg (total dose) per cat PO in the evening | PO | q12h or q24h | — | 🌎 NA |
| Tracheal collapse (mild clinical signs, <50% collapse) | aminophylline: 5 mg/kg PO, two times daily. | PO | q12h | — | 🌎 NA |
| Bronchoconstriction associated with fulminant CHF | Aminophylline 4-8 mg/kg SC, IM, IV q8-12h. | SC/IM/IV | q8-12h | — | 🌎 NA |
| Cough | Aminophylline: 5 mg/kg PO twice daily | PO | q12h | — | 🌎 NA |
- Bronchodilation (Extended-Release): Products Theo-Dur and Slo-Bid are no longer available in the USA. Cautious use of dog dose/products is a reasonable alternative.
- Bronchodilation: Using aminophylline tablets or sustained release tablets
フェレット
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Bronchodilation | 4.25 mg/kg PO 2-3 times a day | PO | q8-12h | — | 🌎 NA |
馬
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Pulmonary edema | Aminophylline 2-7 mg/kg IV q6-12h; Theophylline 5-15 mg/kg PO q12h | IV/PO | q6-12h | — | 🌎 NA |
| Pulmonary edema | 11 mg/kg PO or IV q8-12h. | PO/IV | q8-12h | — | 🌎 NA |
| Heaves (RAO) | Aminophylline: 5-10 mg/kg PO or IV twice daily. | PO/IV | q12h | — | 🌎 NA |
| Heaves (RAO) | Aminophylline: 4-6 mg/kg PO three times a day. | PO | q8h | — | 🌎 NA |
- Pulmonary edema: IV aminophylline should be diluted in at least 100 mL of D5W or normal saline and administered slowly (not >25 mg/min).
- Pulmonary edema: To 'load' may either double the initial dose or give both oral and IV dose at the same time. IV infusion in ~1L fluids over 20-60 mins.
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
アミノフィリンおよびテオフィリンは、獣医学において主に強力な気管支拡張薬として利用されるメチルキサンチン誘導体です。猫の喘息、馬の回帰性気道閉塞（RAO）、犬の気管支炎などの下気道疾患、気管虚脱の管理、および心原性肺水腫の補助療法として頻繁に使用されます。
臨床のポイント： アミノフィリンは本質的にテオフィリンの水溶性塩であり、エチレンジアミンを付加することで生成されます。100mgの含水アミノフィリンには約79mgの無水テオフィリンが含まれています。 2つの形態間で切り替える場合は、用量換算を慎重に行う必要があります。
これらの薬剤は非常に有効ですが、治療域が狭い（狭い治療指数）という特徴があります。毒性は用量依存的ですが、犬や猫は一般的に人間よりも高い血清濃度に耐容性を示します。代謝における個体差が大きいため、特に肝疾患や心疾患を併発している患者では、治療薬物モニタリング（TDM）が強く推奨されます。
作用機序
The primary mechanism of action involves the competitive inhibition of phosphodiesterase (PDE) enzymes.
- PDE Inhibition → Decreased breakdown of cyclic AMP (cAMP) → Elevated intracellular cAMP levels.
- Increased cAMP → Enhanced release of endogenous epinephrine → Relaxation of bronchial and pulmonary vascular smooth muscle.
- Elevated cAMP also inhibits the release of inflammatory mediators like histamine and slow-reacting substance of anaphylaxis (SRS-A) from mast cells.
- Intracellular Calcium Translocation: Methylxanthines alter intracellular ionized calcium dynamics, contributing to increased diaphragmatic contractility (reducing respiratory fatigue) and weak positive inotropic/chronotropic effects on the heart.
- Additional Effects: Induces mild diuresis, stimulates the central nervous system (CNS) and respiratory centers, and increases gastric acid secretion.
安全性・警告
禁忌
- Hypersensitivity to any xanthines (including theobromine or caffeine)
- Hypersensitivity to ethylenediamine (specific to aminophylline)
有害事象
- Nausea and vomiting
- Diarrhea
- Insomnia / Restlessness
- Polyphagia (increased appetite)
- Polydipsia and polyuria (increased thirst and urination)
- Tachycardia (rapid heart rate)
- Nervousness, excitability, and tremors (especially in horses)
- Diaphoresis (sweating in horses)
- Ataxia
- Seizures (in severe toxicity)
- Cardiac dysrhythmias (in severe toxicity)
注意事項
Use with extreme caution in patients with severe cardiac disease, seizure disorders, gastric ulcers, hyperthyroidism, renal or hepatic disease, severe hypoxia, or severe hypertension.
- Arrhythmias: May cause or worsen preexisting cardiac arrhythmias; enhanced monitoring is required.
- Clearance Issues: Neonatal, geriatric, and congestive heart failure (CHF) patients may have decreased clearance and prolonged half-lives, making them more susceptible to toxicity.
- Dosing Weight: Because of low lipid solubility and low volume of distribution, obese patients should be dosed based on lean body weight.
- IM Injection: Aminophylline causes intense local pain when administered IM and is rarely recommended via this route.
医薬品相互作用
May decrease theophylline levels via hepatic enzyme induction.
Can significantly increase theophylline levels. Consider reducing theophylline dose by 30% and monitor for toxicity.
Can increase theophylline levels.
Can increase theophylline levels by inhibiting hepatic metabolism.
Concurrent use can cause an increased incidence of seizures.
Concurrent use may cause an increased incidence of cardiac dysrhythmias.
Toxic synergism; can lead to severe cardiac arrhythmias.
Can increase theophylline levels and antagonize bronchodilatory effects.
Can increase theophylline levels.
監視
- Therapeutic efficacy (improvement in breathing/cough)
- Clinical signs of toxicity (GI upset, CNS stimulation, tachycardia)
- Serum trough levels at steady state (Target: >8-10 mcg/mL in small animals; do not exceed 15 mcg/mL in horses. Human therapeutic range is 10-20 mcg/mL)
薬物動態
半減期
吸収
Nearly 100% bioavailable after oral administration of non-sustained release products. Sustained-release products have variable bioavailability ranging from 30-76%.
分布
Distributes throughout extracellular fluids and body tissues. Crosses the placenta and distributes into milk (70% of serum levels). Low plasma protein binding (7-14% in dogs). Volume of distribution: dogs 0.82 L/kg, cats 0.46 L/kg, horses 0.85-1.02 L/kg.
代謝
Metabolized primarily in the liver to 3-methylxanthine, which possesses weak bronchodilatory activity.
消失
Renal clearance contributes only about 10% to overall plasma clearance.
過剰投与
Clinical signs of toxicity are usually associated with serum levels greater than 20 mcg/mL in humans, though dogs appear to tolerate higher levels.
Life-threatening signs:
- Tachycardia and severe cardiac arrhythmias
- CNS effects including seizures and hyperthermia
Treatment is supportive:
- Decontamination: Empty the gut, administer activated charcoal and a cathartic if oral ingestion was recent.
- Seizures: Maintain an adequate airway and treat with IV diazepam.
- Monitoring: Continuous ECG monitoring for arrhythmias. Monitor and correct fluid/electrolyte imbalances.
- Symptomatic Care: Hyperthermia may be treated with phenothiazines; severe tachycardia may be treated with propranolol if life-threatening.
製品
製剤
- Tablets (immediate and extended-release)
- Capsules (extended-release)
- Injection (solution)
- Oral elixir/solution
- Compounded oral suspension
ヒト用医薬品
- Aminophylline Tablets: 100 mg & 200 mg
- Aminophylline Injection: 250 mg/10 mL (25 mg/mL)
- Theophylline Extended-Release Capsules and Tablets: 100 mg, 125 mg, 200 mg, 300 mg, 400 mg, 450 mg, & 600 mg
- Theophylline Tablets and Capsules: 100 mg, 200 mg, & 300 mg
- Theophylline Elixir: 80 mg/15 mL
- Theophylline & Dextrose Injection: Various concentrations (0.4 mg/mL to 4 mg/mL)
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
Store oral products in tight, light-resistant containers at room temperature. Aminophylline injection should be stored below 30°C, protected from freezing and light. Do not inject solutions that contain a precipitate or visible crystals. Compounded oral suspensions should be protected from light and kept at room temperature (refrigeration causes precipitation).
飼主向け情報
この薬は、ペットの気道を広げ、呼吸を楽にするために使用されます。
- 投薬方法： 獣医師の指示通りに正確に投薬してください。用量を飛ばさないでください。徐放性（効果が長続きする）の錠剤やカプセルを使用している場合、獣医師からの特別な指示がない限り、砕いたり、ペットに噛ませたりしないでください。
- 副作用： 投薬開始時に、軽度の胃腸の不調、飲水量や尿量の増加、またはわずかな落ち着きのなさが生じることがありますが、通常は自然に治まります。
- 獣医師に連絡すべき場合： 激しい嘔吐、極度の落ち着きのなさ、筋肉の震え、速い呼吸、または発作が見られた場合は、過剰投与の兆候である可能性があるため、直ちに獣医師に連絡してください。
- 食事： チョコレートやカフェインを与えないでください。これらには類似の成分が含まれており、毒性のリスクを高める可能性があります。
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。