曲唑酮
曲唑酮 (Trazodone) 是一種**血清素2A拮抗劑/再攝取抑制劑 (SARI)**，在獸醫學中廣泛用作抗焦慮藥和溫和的鎮靜劑。 - **臨床應用**：對於情境性焦慮（如雷暴、煙火、看獸醫、旅行）以及協助術後限制活動或籠內休息非常有效。 - **輔助治療**：常與 SSRI（如氟西汀）或加巴噴丁 (Gabapentin) 併用，治療難治性行為障礙。 - **安全性**：耐受性良好，安全範圍廣，與三環類抗憂鬱藥 (TCA) 相比，其抗膽鹼能副作用較少，引發癲癇的風險也較低。 - **人類用途**：用於治療憂鬱症、攻擊行為、酒精或古柯鹼戒斷、偏頭痛預防及失眠。
作用機制: Trazodone exerts its anxiolytic and sedative effects through multiple neurochemical pathways: - **Serotonin Reuptake Inhibition**: Blocks the serotonin transporter (SERT) → increases extracellular serotonin (5-HT) in the synaptic cleft. - **5-HT2A Receptor Antagonism**: Blocks 5-HT2A receptors → prevents overstimulation by serotonin, contributing to its anxiolytic and antidepressant efficacy. Downregulation of these receptors can augment the efficacy of concurrent SSRIs. - **Active Metabolite**: Hepatic metabolism produces **m-chlorophenylpiperazine (mCPP)**, which acts as a direct, non-selective serotonin receptor agonist. - **Alpha-1 Adrenergic Antagonism**: Blocks peripheral alpha-1 receptors → can cause mild vasodilation and hypotension. - **Histamine (H1) Antagonism**: Weak blockade of H1 receptors contributes to its sedative properties.
各物種劑量
- Adjunctive treatment of anxiety-related disorders (Daily medication only) · 1.9 mg/kg/day-16.2 mg/kg/day (mean = 7.3 mg/kg/day) · PO · daily · Begin at half target dose for 3 days to build tolerance.
- Adjunctive treatment of anxiety-related disorders (As needed only) · 2.2 mg/kg/day- 14 mg/kg/day (mean 7.7 mg/kg/day) · PO · PRN
- Adjunctive treatment of anxiety-related disorders (Daily medication and as needed) · 1.7 mg/kg/day-19.5 mg/kg/day (mean 7.25 mg/kg/day) · PO · daily and PRN
- Adjunctive treatment of anxiety-related disorders · 1 mg/kg PO q12h for 7 days, then up to 3 mg/kg PO q12h. · PO · q12h · 7 days initially
- Adjunctive treatment of anxiety-related disorders · 1-4.8 mg/kg PO twice daily; (titrate to effect in 1 mg increments every 7 days). · PO · q12h
- Adjunctive treatment of anxiety-related disorders (Situational) · typical starting dose between 2-5 mg/kg and adjusting upwards as necessary to get control (maximum dose 14 mg/kg/day). · PO · PRN · Given about an hour prior to the onset of anxiety.
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
- Hypersensitivity to trazodone
- Concurrent use of MAO inhibitors (e.g., amitraz, selegiline)
- Glaucoma
- History of seizures
- Urinary retention
- Severe liver disease
不良反應
- Sedation
- Lethargy
- Ataxia
- Cardiac conduction disturbances
- Increased anxiety (paradoxical)
- Aggression (paradoxical)
- Vomiting/gagging
- Increased excitement
- Increased appetite
- Colitis
- Serotonin syndrome (rare, usually with concurrent serotonergic drugs)
- Vomiting
- Excitability
- Dry mouth
- Third eyelid protrusion (in cats)
藥物相互作用
- Antihypertensive drugs · May increase reductions in blood pressure and cause hypotension
- Aspirin · Increase risk for GI bleeding; monitor
- Azole antifungals (e.g., ketoconazole, fluconazole) · May increase trazodone blood levels
- CNS depressants · Use with trazodone may cause additive CNS depressant effects
- Digoxin · Trazodone may increase digoxin levels
- Macrolide antibiotics (e.g., erythromycin, clarithromycin) · May increase trazodone blood levels
- Metoclopramide · Increased risk for serotonin syndrome
- NSAIDs · Increased risk for GI bleeding; monitor
- Phenothiazines · May increase trazodone blood levels; cause additive CNS effects
- SSRI antidepressants (e.g., fluoxetine) · Increased risk for serotonin syndrome. Commonly used together, but monitor closely.
- Monoamine oxidase inhibitors (MAOIs) · Contraindicated; high risk of serotonin syndrome · major
- Chlorphenamine · Metabolized by CYP450 2D6; potential for altered metabolism and toxicity · moderate
- Cimetidine · Metabolized by CYP450 2D6; potential for altered metabolism and toxicity · moderate
監測
- Clinical efficacy (behavioral calming)
- Adverse effects (sedation, GI upset, paradoxical excitement)
- Signs of serotonin syndrome (vomiting, diarrhea, seizures, hyperthermia, hyperesthesia, mydriasis)
- Renal function (in patients with pre-existing renal disease)
- Signs of serotonin syndrome (tremors, agitation, hyperthermia)
- Efficacy of anxiety reduction
過量
No specific information is available regarding trazodone overdoses in veterinary patients. In humans, the incidence of serious toxicity from trazodone overdose alone is low compared with tricyclic antidepressant overdoses. In the event of a substantial overdose, contact an animal poison control center for guidance. Monitor for profound sedation, ataxia, hypotension, and signs of serotonin syndrome.
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。