卡比馬唑
**卡比馬唑 (Carbimazole)** 是一種硫咪唑衍生物的**抗甲狀腺**藥物，在獸醫學中主要用於控制**貓甲狀腺機能亢進**。 * 它是一種**前驅藥 (prodrug)**，在體內會迅速轉化為**甲巰咪唑 (methimazole)**。 * 因為它沒有甲巰咪唑的苦味，貓咪的接受度通常較高，能減少腸胃道副作用的發生率。 * 雖然在美國或加拿大未上市，但在歐洲及其他地區被廣泛使用。 * **臨床重點**：由於分子量的差異，卡比馬唑需要大約兩倍於甲巰咪唑的毫克劑量，才能達到相等的血清濃度。
作用機制: 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.
各物種劑量
- 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 · Do not break tablets. Note: There are no data on the use of the sustained-release formulation in dogs.
- Hyperthyroidism · 2.5-5 mg (total dose) per cat · PO · twice daily
- Hyperthyroidism · 10-15 mg total dose daily per cat in divided doses · PO · divided doses · for 1-3 weeks · 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 · Initially, give 5 mg (total dose) · PO · q8h · for 2-3 weeks · 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) · 15 mg · PO · once daily · 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 · 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 · Do not break tablets.
劑量為持牌獸醫專業人員的臨床參考。請務必對照最新藥品說明書及個別病患確認。
給藥途徑
禁忌症
- Hypersensitivity to carbimazole or methimazole
- Not recommended in cats intolerant to methimazole
- History of or concurrent hematologic abnormalities
- Liver disease
- Autoimmune disease
不良反應
- 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)
藥物相互作用
- Bupropion · Potential for increased risk for hepatotoxicity; increased monitoring (LFT's) necessary
- Digoxin · Carbimazole may decrease digoxin efficacy
- Warfarin · Potential for decreased anticoagulant efficacy if carbimazole added
- Iodine-131 (Radioiodine) · Carbimazole interferes with the uptake and efficacy of radioiodine therapy. It must be discontinued prior to treatment. · major
- Low iodine prescription diets · Concurrent use is not recommended as it may interfere with the dietary management of hyperthyroidism. · major
監測
- 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
過量
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.
VetSheet 藥物參考供持牌獸醫專業人員作臨床決策輔助之用,不能取代專業判斷或廠方最新藥品說明書。