カルビマゾール
Carbimazole
Thioimidazole-derivative antithyroid drug
別名: Vidalta · Neo-Carbimazole · Carbazole · Basolest · Camazol · Carbistad · Neo Tomizol · NeoMercazole · Neo-Thyreostat · Thyrostat · Tyrazol · Neo-morphazole · Neo-Mercazole · carbimazolum
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 |
|---|---|---|---|---|---|
| Hyperthyroidism | 15 mg/animal (starting dose) or 10 mg/animal if total thyroxine <100 nmol/l. Adjust dose in 5 mg increments. | PO | q24h | Long-term | 🌍 EU |
- Hyperthyroidism: Do not break tablets. Note: There are no data on the use of the sustained-release formulation in dogs.
猫
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Hyperthyroidism | 2.5-5 mg (total dose) per cat | PO | twice daily | — | 🌎 NA |
| Hyperthyroidism | 10-15 mg total dose daily per cat in divided doses | PO | divided doses | for 1-3 weeks | 🌎 NA |
| Hyperthyroidism | Initially, give 5 mg (total dose) | PO | q8h | for 2-3 weeks | 🌎 NA |
| Hyperthyroidism (Sustained-release tablets) | 15 mg | PO | once daily | — | 🌎 NA |
| Hyperthyroidism | 15 mg/animal (starting dose) or 10 mg/animal if total thyroxine <100 nmol/l. Adjust dose in 5 mg increments. | PO | q24h | Long-term | 🌍 EU |
- Hyperthyroidism: Will produce a euthyroid state for most patients. Then adjust dosage for the patient to the lowest effective dose. Most cats will need dosing at least once daily.
- Hyperthyroidism: Then adjust. May need to increase dose in approximately 10% of cats. Most cats require 5 mg PO q12h to maintain euthyroidism.
- Hyperthyroidism (Sustained-release tablets): Give at the same time each day. Do not break or crush tabs. Adjust dose upwards or downwards within a range of 10 mg-25 mg per day in 5 mg increments depending on clinical signs and TT4. If cat requires doses less than 10 mg per day, use alternative treatment.
- Hyperthyroidism: Do not break tablets.
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
カルビマゾール (Carbimazole) は、主に獣医療において猫の甲状腺機能亢進症の管理に使用されるチオイミダゾール誘導体の抗甲状腺薬です。
- これはプロドラッグであり、生体内で速やかにメチマゾール (methimazole) に変換されます。
- メチマゾールのような苦味がないため、猫にとって許容性が高く、胃腸の副作用の発生率を低下させます。
- 米国やカナダでは入手できませんが、ヨーロッパやその他の地域で広く使用されています。
- 臨床のポイント: 分子量の違いにより、同等の血清濃度を達成するためには、メチマゾールの約2倍のミリグラム用量が必要です。
作用機序
Carbimazole is a prodrug that is almost entirely converted to methimazole in the body.
- Methimazole actively inhibits the enzyme thyroid peroxidase (TPO).
- Inhibition of TPO → blocks the oxidation of iodide to iodine → prevents iodine incorporation into tyrosyl residues of thyroglobulin.
- It also inhibits the coupling of iodinated tyrosyl residues (monoiodotyrosine and diiodotyrosine) → prevents formation of thyroxine (T4) and triiodothyronine (T3).
- Note: It does not affect the release or activity of pre-formed thyroid hormones already in circulation, which accounts for the 1-3 week lag time before clinical improvement is seen.
安全性・警告
禁忌
- Hypersensitivity to carbimazole or methimazole
- Not recommended in cats intolerant to methimazole
- History of or concurrent hematologic abnormalities
- Liver disease
- Autoimmune disease
有害事象
- Vomiting
- Anorexia
- Depression
- Eosinophilia (usually transient)
- Leukopenia (usually transient)
- Lymphocytosis (usually transient)
- Self-induced excoriations (rare but serious)
- Bleeding (rare but serious)
- Hepatopathy (rare but serious)
- Thrombocytopenia (rare but serious)
- Agranulocytosis (rare but serious)
- Positive direct antiglobulin test (rare but serious)
- Acquired myasthenia gravis (rare but serious)
- Positive ANA (with chronic use)
注意事項
Hypersensitivity: Contraindicated in patients hypersensitive to carbimazole or methimazole. Cross-Reactivity: Because carbimazole is a prodrug converted into methimazole, cats who have had prior serious reactions to methimazole should receive carbimazole with great caution. Pregnancy/Nursing: High levels of methimazole cross the placenta and may induce hypothyroidism in kittens. Levels higher than those found in plasma are found in breast milk. Kittens should be placed on a milk replacer after receiving colostrum from mothers on methimazole. FDA categorizes methimazole as category D for use during pregnancy.
医薬品相互作用
Potential for increased risk for hepatotoxicity; increased monitoring (LFT's) necessary
Carbimazole may decrease digoxin efficacy
Potential for decreased anticoagulant efficacy if carbimazole added
Carbimazole interferes with the uptake and efficacy of radioiodine therapy. It must be discontinued prior to treatment.
Concurrent use is not recommended as it may interfere with the dietary management of hyperthyroidism.
監視
- CBC, platelet counts (baseline and every 2-3 weeks during first 3 months)
- Serum T4 (baseline and every 2-3 weeks during first 3 months)
- Liver function tests (if indicated by clinical signs)
- ANA (if indicated by clinical signs)
- T4 at 3-6 month intervals (after stabilized)
- Other diagnostic tests as dictated by adverse effects
薬物動態
半減期
吸収
Rapidly absorbed from the GI tract.
分布
In cats, the volume of distribution of methimazole is variable (0.12-0.84 L/kg). Methimazole apparently concentrates in thyroid tissue and biologic effects persist beyond measurable blood levels. Crosses the placenta and enters breast milk.
代謝
Rapidly and nearly totally converted to methimazole in vivo.
消失
Plasma elimination half-life of methimazole ranges from 2.3-10.2 hours in cats and 8-9 hours in dogs.
過剰投与
Acute toxicity that may be seen with overdosage includes vomiting, anorexia, depression, and more serious effects such as agranulocytosis, hepatopathy, and thrombocytopenias.
Treatment: Consists of following standard protocols in handling an oral ingestion (empty stomach if not contraindicated, administer charcoal, etc.) and treating symptomatically and supportively.
製品
製剤
- Oral Tablets
- Oral Sustained-Release Tablets
動物用医薬品
- Carbimazole Oral Sustained-Release Tablets: 10 mg & 15 mg (Vidalta, Intervet-UK)
ヒト用医薬品
- Carbimazole Oral Tablets: 5 mg & 20 mg (NeoCarbimazole, Carbazole, Neo Mercazole)
規制ステータス
Approved for feline hyperthyroidism.
POM-V (Prescription Only Medicine - Veterinarian)
規制データなし: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
保管・安定性
Unless otherwise labeled, carbimazole tablets should be stored at room temperature in well-closed containers.
飼主向け情報
- 目的: この薬は、甲状腺ホルモンの産生を抑えることで、猫の甲状腺機能亢進症を管理します。これは対症療法であり、完治させるものではありません。
- 効果が現れるまで: 猫の症状に明らかな改善が見られるまで、通常1〜3週間かかります。
- 投与方法: 処方された通りに正確に投与してください。徐放錠（Vidaltaなど）は砕いたり割ったりしないでください。
- 注意すべき副作用: 猫が嘔吐、食欲不振、無気力、または顔を激しく掻くなどの症状を示した場合は、獣医師に連絡してください。
- 安全性: 胎盤を通過し母乳に移行する可能性があるため、妊娠中または授乳中の女性はこの薬の取り扱いに注意してください（手袋の着用を推奨します）。
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。