吡哆醇 (維生素B6)
**吡哆醇 (維生素B6)** 是一種水溶性維生素，對許多代謝過程至關重要。在獸醫學中，其主要特定適應症是作為異煙肼 (INH) 或鼠毒強 (crimidine) 中毒的**解毒劑**，以及延緩與微脂體小紅莓 (**Doxil®**) 相關的皮膚毒性（掌蹠紅斑感覺異常症候群）。 *臨床提示*：雖然食用均衡商業飲食的犬貓很少出現飲食缺乏，但患有嚴重胃腸道疾病的貓可能對吡哆醇的需求增加。此外，體外研究表明，吡哆醇可以抑制貓乳腺腫瘤的生長。
作用機制: Pyridoxine is converted in erythrocytes to **pyridoxal phosphate** and, to a lesser extent, **pyridoxamine**, which act as vital coenzymes for protein, lipid, and carbohydrate utilization. * **Neurotransmitter Synthesis**: Required for the synthesis of **GABA** (gamma-aminobutyric acid) in the CNS, and the conversion of tryptophan → **serotonin** or niacin. * **Metabolic Pathways**: Essential for glycogen breakdown, heme synthesis, and the conversion of oxalate → glycine. * **Toxicity Antidote**: Acts as an antidote by directly enhancing the renal excretion of cycloserine and isoniazid.
各物種劑量
- To replace pyridoxine antagonized by crimidine ingestion · 20 mg/kg · IV · Once
- Isoniazid (INH) toxicity · If quantity of INH ingested is known, give pyridoxine on a mg for mg (1:1) basis. If it is not known, give pyridoxine initially at 71 mg/kg as a 5-10% IV infusion over 30-60 minutes · IV · Once · Some sources say it can be given as an IV bolus. Do not use injectable B-complex vitamins.
- To replace pyridoxine antagonized by crimidine ingestion · 20 mg/kg · IV · Once
- To delay the development of cutaneous toxicity (PPES) associated with doxorubicin containing pegylated liposomes (Doxil®) · 50 mg · PO · q8h (three times daily) · During chemotherapy protocol period
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
- Documented hypersensitivity or sensitivity to pyridoxine
不良反應
- Paresthesias (reported in humans)
- Somnolence (reported in humans)
- Reduced serum folic acid levels
- Peripheral neuropathy (associated with massive overdoses)
藥物相互作用
- Chloramphenicol · May cause increased pyridoxine requirements
- Estrogens · May cause increased pyridoxine requirements
- Hydralazine · May cause increased pyridoxine requirements
- Immunosuppressants (e.g., azathioprine, chlorambucil, cyclophosphamide, corticosteroids) · May cause increased pyridoxine requirements
- Isoniazid · May cause increased pyridoxine requirements
- Penicillamine · May cause increased pyridoxine requirements
- Levodopa · Pyridoxine may reduce levodopa efficacy (no interaction when levodopa is used with carbidopa)
- Phenobarbital · High dose pyridoxine may decrease phenobarbital serum levels
- Phenytoin · High dose pyridoxine may decrease phenytoin serum concentration
監測
- Efficacy for intended use
- Neurologic signs (gait, coordination) if on high doses
過量
> **Warning**: While single overdoses are generally not problematic unless massive, chronic high doses can cause severe neurologic toxicity. * **Massive Acute Overdose**: Laboratory animals given 3-4 grams/kg developed seizures and died. * **Chronic Overdose**: Dogs (Beagles) repeatedly given 3 gram oral daily doses developed uncoordinated gait and neurologic signs. Neuronal lesions were noted in sensory, dorsal root ganglia, and trigeminal ganglia. Signs generally resolved over a 2-month drug-free period.
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。