アレンドロン酸ナトリウム
Alendronate Sodium
(4-amino-1-hydroxy-1-phosphono-butyl) phosphonic acid
別名: Fosamax · Adronat · Alendros · Arendal · Onclast · Alendronic acid · Acide Alendronique · Acido Alendronico · Acidum Alendronicum
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 |
|---|---|---|---|---|---|
| Refractory hypercalcemia | 0.5-1 mg/kg | PO | once daily | — | 🌎 NA |
| Investigational treatment of histiocytic sarcoma complex | Loading dose of 70 mg/m 2 (NOT mg/kg) | PO | daily for 14 days, then every other day for 14 days, then once weekly | — | 🌎 NA |
- Investigational treatment of histiocytic sarcoma complex: Monitor for esophageal problems (excessive salivation, regurgitation).
猫
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Feline odontoclastic resorptive lesions (FORLs) | 3 mg/kg | PO | q12h | — | 🌎 NA |
| Idiopathic hypercalcemia (after dietary change has been attempted) | Initially 2 mg/kg. Most cats respond to 10 mg (total dose). | PO | once weekly | — | 🌎 NA |
- Feline odontoclastic resorptive lesions (FORLs): Note: Use for this indication in cats is at present very controversial. (Plumb 2006)
- Idiopathic hypercalcemia (after dietary change has been attempted): Administer at least 6 mL of water after administration and butter the lips to increase salivation and increase transit. If efficacious, effects usually seen in 3-4 weeks. Monitor via serum ionized calcium.
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
アレンドロン酸ナトリウムは、主に破骨細胞による骨吸収を抑制するために使用される経口投与型の含窒素ビスホスホネートです。
主な臨床的特徴：
- 主な適応症： 獣医学では、難治性高カルシウム血症（猫の特発性高カルシウム血症、悪性腫瘍に伴う高カルシウム血症など）、猫の破歯細胞性吸収病巣（FORLs）、および骨肉瘤や組織球肉腫の補助治療として使用されます。
- 試験的段階： 小動物における臨床経験はまだ非常に限られています。投与量や安全性プロファイルは現在も確立中です。
- バイオアベイラビリティの課題： 経口吸収率は極めて低く（2%未満）、食事によってさらに著しく低下するため、厳格な絶食プロトコルが必要です。
- 食道へのリスク： ヒトにおいて重度の食道刺激やびらんを引き起こすことが知られており、ペットにおいては胃への迅速な移行を確実にするための特別な投与技術（水を追加で飲ませる、唇にバターを塗るなど）が必要です。
作用機序
Alendronate is a nitrogenous bisphosphonate that strongly binds to hydroxyapatite crystals in the bone matrix.
- Mechanism: During bone resorption, the drug is locally released and endocytosed by osteoclasts.
- Intracellular Pathway: Inside the osteoclast, alendronate inhibits the enzyme farnesyl pyrophosphate synthase (FPPS) within the mevalonate pathway → prevents the prenylation (lipid modification) of small GTP-binding proteins (such as Ras, Rho, and Rab) → disrupts osteoclast cytoskeletal organization and ruffled border formation → induces osteoclast apoptosis.
- Secondary Effects: By inhibiting osteoclastogenesis and promoting apoptosis, it indirectly reduces angiogenesis and may inhibit cancer cell proliferation in osteogenic neoplasms.
安全性・警告
禁忌
- Esophageal abnormalities (e.g., strictures, achalasia) that delay esophageal emptying
- Inability to stand or sit upright for 30 minutes post-administration (human guideline; veterinary relevance is managed via water chasers/activity)
- Severe renal dysfunction (Creatinine Clearance < 35 mL/min)
- Known hypersensitivity to alendronate or other bisphosphonates
有害事象
- Upper GI irritation and erosions
- Esophageal stricture or ulceration
- Vomiting
- Inappetence
- Jaw osteonecrosis (rare but documented in humans)
- Musculoskeletal pain
- Hypocalcemia (with overdose)
- Hypophosphatemia (with overdose)
注意事項
Esophageal Toxicity Warning: Alendronate can cause severe local irritation to the upper gastrointestinal mucosa.
- Administration Technique: To minimize esophageal transit time and prevent erosions, ensure the patient swallows the medication completely. In dogs, walking or playing for 30 minutes post-dose is recommended. In cats, administering at least 6 mL of water and buttering the lips to induce salivation is advised.
- Renal Impairment: Use with extreme caution or avoid in patients with severe renal dysfunction.
- Investigational Use: Inform owners that the use of this drug in veterinary medicine is largely investigational, and long-term safety data is lacking.
医薬品相互作用
Increased risk of upper GI adverse effects and erosions.
Likely to significantly decrease the already low oral bioavailability of alendronate.
Increased oral alendronate bioavailability two-fold in a human study.
Humans taking NSAIDs with alendronate had no higher rates of GI adverse reactions than when NSAIDs were used with placebo, though caution is still advised.
Significantly decreases alendronate absorption
Decreases alendronate absorption
監視
- Serum ionized calcium
- Serum phosphorus
- Serum potassium and sodium
- Signs of GI adverse effects (excessive salivation, regurgitation, dysphagia, inappetence)
薬物動態
半減期
吸収
Oral bioavailability is extremely low (<2% in all studied species; <1% in humans). The presence of food, coffee, or juice can reduce bioavailability further to negligible amounts.
分布
Absorbed drug is rapidly distributed to bone or excreted into the urine. Accumulates on subgingival tooth surfaces and bordering alveolar bone. Not highly plasma protein bound in dogs (but is in rats). Plasma concentrations are virtually undetectable after therapeutic dosing.
代謝
Alendronate is not metabolized.
消失
Drug taken up by bone is very slowly eliminated. Once incorporated into bone, alendronate is no longer active.
過剰投与
Toxicity Profile: No lethality was observed in dogs receiving doses up to 200 mg/kg. Lethality in rodents occurs at >550 mg/kg.
Clinical Signs of Overdose: Hypocalcemia, hypophosphatemia, and severe upper GI reactions (ulceration, erosions).
Treatment:
- DO NOT induce vomiting due to the risk of severe esophageal irritation.
- Administer oral antacids or milk immediately to bind the drug and prevent systemic absorption.
- Monitor serum calcium and phosphorus levels closely.
- Provide supportive care as needed.
製品
製剤
- Oral tablets
- Oral solution
ヒト用医薬品
- Alendronate Sodium Oral Tablets: 5 mg, 10 mg, 35 mg, 40 mg, & 70 mg (Fosamax, generic)
- Alendronate Oral Solution: 70 mg (as base) in 75 mL; raspberry flavor (Fosamax)
規制ステータス
POM (Prescription Only Medicine)
POM (Prescription Only Medicine)
規制データなし: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
保管・安定性
Alendronate tablets should be stored in well-closed containers at room temperature. The oral solution should be stored at room temperature; do not freeze.
飼主向け情報
飼い主様への重要な投与指示：
- 厳格な絶食： この薬は食事と一緒に与えると吸収されません。必ず空腹時に投与し、投与後少なくとも30分間は食事を与えないでください。
- 食道損傷の予防： アレンドロン酸が食道に留まると、重度の潰瘍を引き起こす可能性があります。
- 犬の場合： 薬が確実に胃に到達するよう、投薬後30分間は犬と散歩したり遊んだりして、体を起こした状態を保ってください。
- 猫の場合： 投薬後すぐに、シリンジで少なくとも6 mL（約小さじ1杯）の水を飲ませてください。その後、猫の唇にバターを塗ると、唾液の分泌と嚥下が促され、薬が安全に胃に落ちるのを助けます。
- 副作用の観察： よだれ、吐き戻し、嚥下困難、嘔吐、または食欲不振の兆候が見られた場合は、直ちに獣医師にご連絡ください。
- 試験的な使用： 獣医学におけるこの薬の使用は比較的新しく、ペットに対する長期的な影響は現在も研究中であることをご理解ください。
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