牛磺酸
牛磺酸是一種β-氨基酸，雖然在許多哺乳動物中被認為是「非必需」的，但對**貓咪來說是絕對必需的**，對某些犬種則是條件性必需的。 - **貓咪健康**：貓咪因半胱亞磺酸脫羧酶 (CSAD) 活性低，且必須使用牛磺酸來結合膽汁酸，因此無法合成足夠的牛磺酸。缺乏會導致**貓中央視網膜變性 (FCRD)** 和**擴張性心肌病 (DCM)**。 - **狗狗健康**：某些品種（如美國可卡犬、黃金獵犬、紐芬蘭犬、大麥町、英國鬥牛犬）容易罹患與牛磺酸缺乏相關的擴張性心肌病。 - **其他用途**：作為貓脂肪肝的輔助治療（具有保肝作用且為膽汁結合所需），並因其神經調節作用而作為癲癇的補充療法。
作用機制: - **Synthesis Pathway**: Synthesized *in vivo* from **methionine** and **cysteine** via the enzyme **cysteinesulfinic acid decarboxylase (CSAD)** (a process requiring **Vitamin B6**). - **Bile Acid Conjugation**: Crucial for fat digestion. Cats use taurine almost exclusively for this process, leading to obligate loss in feces. - **Cardiac Function**: Modulates **calcium flux** across cell membranes → provides positive inotropic activity without altering the resting membrane potential, and modulates ionic currents. - **Neuromodulation**: Stabilizes neuronal membranes and exerts a **GABA-like inhibitory effect** in the CNS, which may help raise the seizure threshold and reduce seizure activity. - **Platelet Function**: Reduces platelet aggregation via calcium modulation.
各物種劑量
- For taurine-deficiency related cardiomyopathy · 250 mg (per cat) PO q12-24h · PO · q12-24h · Because taurine is safe and inexpensive, recommend using for any case of myocardial failure.
- Complementary therapy for seizures · 500 mg per cat PO twice daily · PO · q12h · 'May' help decrease seizure activity
- For adjunctive treatment of hepatic lipidosis · 250-500 mg/day · PO · q24h · Taurine may be hepatoprotective and is required for bile conjugation. Cats with hepatic lipidosis waste taurine in their urine.
- For taurine-deficiency related cardiomyopathy in American Cocker Spaniels · 500 mg PO q12h (with 1 gram of carnitine PO q12h) · PO · q12h
- Complementary therapy for seizures · 400 mg/40 lbs of body weight PO twice daily · PO · q12h · 'May' help decrease seizure activity
- For taurine-related cardiomyopathy · 500-1500 mg (total dose) PO per day · PO · q24h
- Dilated cardiomyopathy · 500-1000 mg PO q8-12h for dogs weighing under 25 kg and 1-2 grams PO q8-12h for dogs weighing > 25 kg · PO · q8-12h · Recommended for all American Cocker spaniels; consider in animals with DCM and cysteine/urate urolithiasis (e.g., English Bulldogs, Dalmatians); consider in golden retrievers, Newfoundlands, Portuguese water dogs.
劑量為合格獸醫專業人員的臨床參考。請務必對照最新藥品仿單及個別病患確認。
給藥途徑
不良反應
- Minor GI distress
監測
- Clinical efficacy (improvement in cardiac function, seizure frequency, or hepatic markers)
- Taurine levels (whole blood levels preferable to plasma/serum levels; avoid hemolysis or collection of the buffy coat as it will negate the results)
過量
Toxic potential appears to be very low. No specific acute toxicity information is available, but massive overdoses are likely to be excreted renally without significant harm.
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。