メロキシカム
Meloxicam
4-hydroxy-2-methyl-N-(5-methyl-2-thiazolyl)-2H-1,2-benzothiazine-3-carboxamide-1,1-dioxide
別名: Metacam · Meloxidyl · Loxicom · Mobic · Orocam · Rheumocam · Inflacam · Meloxivet · Meloxicamum
VetSheet 獣医チームが監修更新日 2026年6月3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Analgesia during gastrointestinal stasis
認証済み獣医師の確認が必要
- q24h
必ず考慮する臨床コンテキスト (2)
- Exclude emergent diagnoses (obstruction, enterotoxemia)
- if renal status stable
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
メロキシカムは、オキシカム系に属する広く利用されている非ステロイド性抗炎症薬（NSAID）です。獣医療においては、主に変形性関節症に伴う疼痛および炎症の管理、ならびに術後の疼痛管理に処方されます。
主な特性は以下の通りです：
- 鎮痛作用： 痛みの知覚を軽減します。
- 抗炎症作用： 組織の炎症を抑えます。
- 解熱作用： 熱を下げます。
臨床のポイント： メロキシカムは、1日1回の投与で済む利便性と、嗜好性の高い経口懸濁液が利用可能であることから、小動物臨床において非常に好まれています。これにより、患者の正確な体重に基づいた精密な用量調整が可能です。
作用機序
Meloxicam exerts its therapeutic effects primarily through the inhibition of cyclooxygenase (COX) enzymes, which are responsible for synthesizing prostaglandins from arachidonic acid.
Arachidonic Acid → COX Enzymes → Prostaglandins & Thromboxanes
- COX-1 (Constitutive): Produces prostaglandins that protect the gastric mucosa, maintain normal renal blood flow, and support platelet function.
- COX-2 (Inducible): Upregulated in response to tissue injury and inflammation, producing pro-inflammatory prostaglandins.
Meloxicam is a COX-2 preferential (or COX-2 selective) NSAID at therapeutic doses. This means it preferentially inhibits the COX-2 enzyme, thereby reducing inflammation and pain, while largely sparing the COX-1 enzyme, which theoretically reduces the risk of gastrointestinal and renal side effects compared to non-selective NSAIDs.
安全性・警告
禁忌
- Patients with known hypersensitivity to meloxicam or other NSAIDs
- Active gastrointestinal ulceration or bleeding
- Pre-existing renal, hepatic, or cardiovascular dysfunction
- Hypovolemic, dehydrated, or hypotensive patients (increased risk of renal toxicity)
- Concurrent use of other NSAIDs or corticosteroids
- Bleeding disorders
- Impaired hepatic, cardiac, or renal function
- Hemorrhagic disorders
- Hypersensitivity to NSAIDs
- Dehydrated, hypovolemic, or hypotensive animals
有害事象
- Gastrointestinal upset (vomiting, diarrhea, inappetence)
- Gastrointestinal ulceration or bleeding (melena, hematemesis)
- Renal toxicity (elevated BUN/Creatinine, acute kidney injury)
- Hepatic toxicity (elevated ALT/AST, rare but possible)
- Lethargy or depression
- Renal impairment
- Hepatic enzyme elevation
注意事項
Important Precautions:
- Hydration Status: Ensure patients are well-hydrated and normotensive prior to administration, especially perioperatively, to mitigate the risk of ischemic renal injury.
- Feline Use: In the United States, meloxicam carries a Black Box Warning for cats regarding repeated oral dosing, which has been associated with acute renal failure and death. However, single-dose injections for post-operative pain are approved, and off-label highly titrated, low-dose chronic use is practiced in other countries under strict monitoring.
- Washout Periods: Implement an appropriate washout period (typically 5-7 days) when transitioning a patient from a corticosteroid or another NSAID to meloxicam.
医薬品相互作用
Significantly increases the risk of severe gastrointestinal ulceration and bleeding. Concurrent use is strictly contraindicated.
Additive toxicity; increases risk of GI, renal, and hepatic adverse effects. A washout period is required when switching.
May reduce the efficacy of the ACE inhibitor and increase the risk of renal toxicity.
NSAIDs may reduce the diuretic effect of furosemide.
Increased risk of bleeding complications.
Increased risk of severe gastrointestinal ulceration and bleeding
Increased risk of gastrointestinal and renal toxicity
Potential reduction in hypotensive effect and increased risk of renal toxicity
監視
- Baseline blood work (CBC, Chemistry panel) prior to initiating chronic therapy
- Renal values (BUN, Creatinine, SDMA, USG)
- Hepatic enzymes (ALT, AST, ALP)
- Clinical signs of GI toxicity (vomiting, diarrhea, melena, anorexia)
- Hydration status
- Liver enzymes (ALT, ALP)
- PCV/TP (if GI bleeding suspected)
- Clinical signs of GI upset (vomiting, diarrhea, melena)
薬物動態
半減期
吸収
Well absorbed following oral administration. Peak plasma concentrations are typically reached within 2-4 hours in dogs.
分布
Highly protein-bound (>97%). Penetrates synovial fluid, reaching concentrations approximately 40-50% of those in blood plasma.
代謝
Extensively metabolized in the liver via cytochrome P450 enzymes (oxidation).
消失
Excreted primarily as metabolites in feces (biliary excretion) and urine.
過剰投与
Overdose Management:
Overdosage of meloxicam increases the risk of severe gastrointestinal ulceration, acute renal failure, and hepatic toxicity.
- Recent Ingestion (< 2 hours): Induce emesis (if no contraindications) followed by the administration of activated charcoal to prevent further absorption.
- Gastrointestinal Protection: Initiate GI protectants such as sucralfate, H2-receptor antagonists (e.g., famotidine), or proton pump inhibitors (e.g., omeprazole).
- Renal Protection: Administer intravenous fluid therapy (e.g., Lactated Ringer's or 0.9% NaCl) at diuresis rates for 48-72 hours to support renal perfusion and flush the kidneys.
- Monitoring: Monitor baseline and daily renal panel (BUN, Creatinine, Phosphorus), PCV/TP, and liver enzymes.
製品
製剤
- Oral suspension (0.5 mg/mL, 1.5 mg/mL)
- Injectable solution (5 mg/mL)
- Tablets (1 mg, 2.5 mg, 7.5 mg, 15 mg)
- Transmucosal oral spray
- 0.5 mg/ml oral suspension (cats)
- 1.5 mg/ml oral suspension (dogs)
- 1.0 mg tablet (dogs)
- 2.5 mg tablet (dogs)
- 2 mg/ml injectable solution (cats)
動物用医薬品
- Metacam 1.5 mg/mL Oral Suspension (Dogs)
- Metacam 0.5 mg/mL Oral Suspension (Cats/Dogs)
- Metacam 5 mg/mL Injectable Solution
- Meloxidyl 1.5 mg/mL Oral Suspension
- Loxicom Oral Suspension
- Orocam Transmucosal Spray
- Inflacam
- Meloxivet
- Rheumocam
ヒト用医薬品
- Mobic 7.5 mg Tablets
- Mobic 15 mg Tablets
- Generic meloxicam tablets and capsules
規制ステータス
プール期間: pig meat 5 days · cattle meat 15 days · horse meat 5 days
POM-V status in the UK/EU.
POM-V
規制データなし: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
保管・安定性
Store at controlled room temperature (20-25°C or 68-77°F). Keep oral suspensions tightly closed. Do not freeze.
飼主向け情報
ペットの投薬に関する重要なガイドライン：
- 食事と一緒に与える： 胃の不調を防ぐため、メロキシカムは必ず食事と一緒に、または食後すぐに与えてください。
- 正しいシリンジを使用する： 液体タイプを使用する場合は、正確な用量を投与するために、必ず薬に付属している専用の計量シリンジを使用してください。
- 副作用に注意する： 以下の症状に気づいた場合は、直ちに投薬を中止し、獣医師に連絡してください：
- 嘔吐または下痢
- 黒色便、タール便、または血便
- 食欲不振または食事の拒否
- 無気力、元気消失、または異常な行動
- 飲水量または尿量の増加
重大な警告： ペットがメロキシカムを服用している間は、人間用の鎮痛剤（アスピリン、イブプロフェン、アセトアミノフェンなど）や他の動物用鎮痛剤を絶対に与えないでください。これらを併用すると、致命的な胃潰瘍や腎不全を引き起こす可能性があります。
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