巴氯芬
巴氯芬 (Baclofen) 是一種中樞作用的骨骼肌鬆弛劑。在獸醫學中，主要用於標示外用途，幫助治療犬隻的功能性尿瀦留（透過降低尿道括約肌張力）。 **臨床要點：** * 巴氯芬在動物體內的安全範圍非常狹窄，常因誤食人類藥物而導致嚴重中毒。 * **嚴禁使用於貓。** * 由於在治療劑量下難以穿透血腦屏障，其中樞作用有限，但大量過量會導致嚴重的中樞神經抑制。
作用機制: Baclofen is a structural analog of the inhibitory neurotransmitter **GABA** (gamma-aminobutyric acid). It acts primarily as a **GABA-B receptor agonist** at the spinal cord level. * Activation of **GABA-B receptors** → hyperpolarization of primary afferent nerve terminals → inhibition of the release of excitatory neurotransmitters (such as glutamate and aspartate). * This reduces **gamma efferent neuronal activity**, decreasing the frequency and amplitude of muscle spasms. * In the lower urinary tract, it specifically reduces **striated sphincter tone** in the urethra, facilitating bladder emptying.
各物種劑量
- To treat urinary retention by decreasing urethral resistance · 1-2 mg/kg · PO · q8h
- To treat urinary retention by decreasing urethral resistance · 5-10 mg (total dose) · PO · q8h
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
禁忌症
- Cats (strictly not recommended)
- Hypersensitivity to baclofen
不良反應
- Sedation
- Weakness
- Pruritus
- Salivation
- Gastrointestinal distress (nausea, abdominal cramping)
藥物相互作用
- CNS Depressants · May cause additive CNS depression
監測
- Efficacy (improvement in urination)
- Adverse effects (sedation, weakness, GI signs)
過量
Baclofen has a narrow margin of safety in dogs. * **Toxicity Thresholds:** Deaths have been reported at doses as low as **8 mg/kg**. Clinical signs can appear at doses as low as **1.3 mg/kg**. * **Clinical Signs:** Vomiting, depression, vocalization, hypersalivation, ataxia, hypotonia, muscle twitching, hypothermia, and lethargy. Massive overdoses may cause respiratory depression, coma, or seizures. * **Onset & Duration:** Signs can occur 15 minutes to 7 hours post-ingestion and persist for hours to days. * **Treatment:** * In alert patients, empty the gut (emesis/lavage). * **Avoid** magnesium-containing saline cathartics (may compound CNS depression). * Forced fluid diuresis may enhance excretion. * Mechanical ventilation for respiratory depression. * **Cyproheptadine** (1.1 mg/kg PO or PR) may alleviate vocalization and disorientation. * Atropine may improve ventilation, HR, BP, and body temperature. * Diazepam for seizures. * **Intravenous Lipid Emulsion (ILE)** may be useful as baclofen is lipid-soluble.
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。