アロプリノール
Allopurinol
1,5-dihydro-4H-pyrazolo[3,4-d]pyrimidin-4-one
別名: Zyloprim · Aloprim · Zyloric · Zylapour · allopurinolum · BW-56-158 · HPP · NSC-1390 · oxypurinol (active metabolite) · alloxanthine
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 |
|---|---|---|---|---|---|
| Urate uroliths (dissolution) | 15 mg/kg PO q12h; only in conjunction with low purine foods. | PO | q12h | — | 🌎 NA |
| Urate uroliths (prevention) | 10-20 mg/kg/day | PO | Daily | — | 🌎 NA |
| Urate uroliths (dissolution and prevention) | 7-10 mg/kg PO three times daily | PO | TID | — | 🌎 NA |
| Leishmaniasis (First line treatment) | 10 mg/kg PO twice daily | PO | BID | 6-12 months | 🌎 NA |
| Leishmaniasis (Second line treatment) | 10 mg/kg PO twice daily | PO | BID | 6-12 months | 🌎 NA |
| Leishmaniasis | 20 mg/kg PO q12h | PO | q12h | 9 months | 🌎 NA |
| Leishmaniasis (Alternate protocol alone) | 10 mg/kg PO q8h or 10-20 mg/kg PO q12h | PO | q8h or q12h | 1-4 months | 🌎 NA |
| Leishmaniasis | 10 mg/kg PO twice daily | PO | BID | — | 🌎 NA |
| Leishmaniasis (with renal insufficiency) | 5 mg/kg PO twice daily | PO | BID | — | 🌎 NA |
| Leishmaniasis | 15 mg/kg PO twice daily | PO | BID | months | 🌎 NA |
| Uric acid urolithiasis (Dissolution) | 10 mg/kg p.o. q8h or 15 mg/kg p.o. q12h | PO | q8h or q12h | up to 4 weeks | 🌍 EU |
| Uric acid urolithiasis (Prevention) | 10-15 mg/kg | PO | q24h | — | 🌍 EU |
| Leishmaniosis | 10 mg/kg | PO | q12h | at least 6-12 months | 🌍 EU |
- Urate uroliths (prevention): Preferable to minimize recurrence with dietary therapy to avoid xanthine uroliths.
- Urate uroliths (dissolution and prevention): Goal is to reduce urine urate:creatinine ratio by 50%.
- Leishmaniasis (First line treatment): Used plus Meglumine antimoniate 75-100 mg/kg once daily for 4-8 weeks.
- Leishmaniasis (Second line treatment): Used plus Miltofosine 2 mg/kg PO once daily for 4 weeks OR allopurinol alone.
- Leishmaniasis: With Meglumine antimoniate (100 mg/kg/day SQ) until resolution.
- Leishmaniasis: If possible use with meglumine antimoniate, if not, use alone.
- Leishmaniosis: Use with meglumine antimonate for 1-2 months, or miltefosine for 1 month (NB: this does not result in complete parasitological cure).
猫
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Leishmaniosis | 10-20 mg/kg | PO | q12-24h | — | 🌍 EU |
- Leishmaniosis: Has been shown to be effective (although experience is limited in this species).
鳥
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Gout (budgies and cockatiels) | Crush one 100 mg tablet into 10 mL of water. Add 20 drops of this solution to one ounce of drinking water. | PO | Continuous in water | — | 🌎 NA |
| Gout (parakeets) | Crush one 100 mg tablet into 10 mL of water. Add 20 drops of this solution to one ounce of drinking water or give 1 drop 4 times daily. | PO | Continuous or QID | — | 🌎 NA |
爬虫類
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Elevated uric acid levels in renal disease (lizards) | 20 mg/kg PO once daily | PO | SID | — | 🌎 NA |
| Gout | 20 mg/kg PO once daily | PO | SID | — | 🌎 NA |
| Hyperuricemia (green iguanas) | 25 mg/kg PO daily | PO | SID | — | 🌎 NA |
- Gout: Suggested dosage based upon human data as dose is not established for reptiles.
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
アロプリノールは、獣医学で広く使用されている強力なキサンチンオキシダーゼ阻害薬です。
主な臨床応用は以下の通りです：
- 尿酸塩尿石症： 主に犬（特にダルメシアンなどの好発犬種）の尿酸結石の溶解および予防に使用されます。キサンチン結石の形成を防ぐため、低プリン食と併用する必要があります。
- 犬リーシュマニア症： リーシュマニア静菌薬として作用します。長期管理のためにメグルミンアンチモネートやミルテホシンと併用されることがよくあります。
- 鳥類および爬虫類医学： 鳥類や爬虫類の高尿酸血症の管理および痛風の治療に使用されます。
臨床のポイント： アロプリノールはキサンチンの尿中排泄を増加させるため、食事でのプリン制限を行わずに長期高用量投与すると、逆説的にキサンチン尿石の形成を招く可能性があります。
作用機序
Allopurinol and its primary active metabolite, oxypurinol (alloxanthine), competitively inhibit the enzyme xanthine oxidase.
- Normal Pathway: Hypoxanthine → xanthine oxidase → Xanthine → xanthine oxidase → Uric Acid
- Inhibition: By blocking this enzyme, allopurinol prevents the conversion of oxypurines to uric acid. This decreases serum and urine concentrations of uric acid, while increasing the levels of the more water-soluble precursors (hypoxanthine and xanthine).
In Leishmaniasis: Allopurinol acts as a purine analogue. Leishmania organisms mistakenly incorporate allopurinol metabolites into their RNA, which disrupts protein synthesis and inhibits parasite multiplication.
安全性・警告
禁忌
- Known hypersensitivity to allopurinol
- Red-tailed hawks (anecdotal reports of severe toxicity)
有害事象
- Xanthine urolithiasis (especially with high doses or non-restricted diets)
- Hypersensitivity reactions (rash, erythema)
- Lethargy
- Gastrointestinal upset
- Hepatotoxicity (rare)
- Bone marrow suppression (rare)
注意事項
Prolonged high doses of allopurinol may result in xanthine uroliths; it is highly recommended to use concurrently with a low-purine diet for urolith management. Use with caution and consider dose reduction (e.g., 5 mg/kg PO twice daily) in patients with renal insufficiency.
医薬品相互作用
May increase risks for hypoglycemia and hepato-renal reactions
Increased bone marrow depression may occur
Allopurinol may increase cyclosporine levels
Can increase uric acid levels, antagonizing allopurinol's effect
Allopurinol may reduce the metabolism of warfarin thereby increasing its effect
Thrombocytopenia has occurred in a few human patients when used concurrently
May increase the renal excretion of oxypurinol and thereby reduce xanthine oxidase inhibition; additive effects on blood uric acid may be beneficial
May reduce the solubility of uric acid in the urine and induce urolithiasis
Allopurinol inhibits the metabolism of azathioprine, leading to severe, potentially fatal myelosuppression.
Allopurinol inhibits the metabolism of mercaptopurine, significantly increasing toxicity risk.
Concurrent use increases the risk of cutaneous rash.
May decrease theophylline clearance, increasing the risk of toxicity.
May increase the risk of allopurinol hypersensitivity and toxicity.
Increased risk of skin rashes when used concurrently.
監視
- Urine uric acid (for urolithiasis)
- Adverse effects (rash, lethargy)
- Periodic CBC, liver and renal function tests (e.g., BUN, Creatinine, liver enzymes); especially early in therapy
薬物動態
吸収
Rapidly absorbed following oral administration.
分布
Widely distributed in tissue fluid; not highly bound to plasma proteins.
代謝
Rapidly oxidized to its primary active metabolite, oxypurinol (alloxanthine), which is also a xanthine oxidase inhibitor.
消失
Excreted primarily in the urine as oxypurinol and unchanged allopurinol.
過剰投与
Information on acute overdosage in veterinary species is limited. Massive overdoses may cause gastrointestinal distress (vomiting, diarrhea). Treatment should consist of supportive care and monitoring of renal function. Adequate hydration is important to promote diuresis and excretion.
製品
製剤
- Oral tablets
- Powder for injection (lyophilized)
- Compounded oral suspension
ヒト用医薬品
- Allopurinol Oral Tablets: 100 mg & 300 mg; Zyloprim® (Faro); generic
- Allopurinol Powder for Injection, lyophilized: 500 mg preservative-free in 30 mL vials; Aloprim® (Nabi); generic (Bedford Labs)
規制ステータス
Approved in several EU member states specifically for canine leishmaniosis.
Used under the cascade where specific veterinary licensed products are unavailable.
規制データなし: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
保管・安定性
Tablets should be stored at room temperature in well-closed containers; stable in light and air. Powder for injection should be stored at 25°C (excursions permitted to 15-30°C). Once diluted to ≤6 mg/mL, store at room temperature and use within 10 hours; do not refrigerate. Compounded oral suspensions (20 mg/mL) in Ora-Plus/Ora-Sweet retain >95% potency for 60 days at 5°C and 25°C and should be protected from light.
飼主向け情報
重要： 獣医師から特別な指示がない限り、胃の不快感を最小限に抑えるため、この薬は食後（通常は食後約1時間）に投与してください。
- 食事管理： ペットが尿酸結石の治療を受けている場合は、獣医師が処方した低プリン食を厳格に守ってください。適切な食事療法なしでこの薬を投与すると、別の種類の結石（キサンチン結石）が形成される可能性があります。
- 獣医師への連絡の目安： ペットに発疹が出たり、異常に無気力になったり、具合が悪そうに見える場合は、すぐに獣医師に連絡してください。
- 泌尿器系を洗い流すのを助けるため、ペットが常に新鮮な飲み水にアクセスできるようにしてください。
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