多拉司瓊
多拉司瓊是一種強效的 **5-HT3 受體拮抗劑**，在獸醫學中主要作為止吐藥使用。它對於控制犬貓因癌症化療引起的嚴重噁心和嘔吐特別有效。 * **給藥便利性**：與通常需要每日多次給藥的昂丹司瓊 (ondansetron) 不同，多拉司瓊通常只需**每日一次**給藥。 * **劑型挑戰**：雖然注射劑型在醫院內使用非常方便，但市售的人用口服錠劑（50 毫克和 100 毫克）對於大多數小動物來說太大，無法直接投藥。因此，口服使用通常需要經過藥物調劑 (compounding)。 > **臨床要點**：由於成本和劑型的限制，常規門診通常更傾向於使用馬羅匹坦 (maropitant) 或昂丹司瓊等其他止吐藥，而將多拉司瓊保留用於難治性病例或特定的化療療程。
作用機制: Dolasetron exerts its anti-nausea and antiemetic effects by selectively antagonizing **5-hydroxytryptamine 3 (5-HT3) receptors**. * **Peripheral Pathway**: Chemotherapy and severe GI insults cause the release of serotonin from mucosal enterochromaffin cells in the small intestine. Serotonin binds to 5-HT3 receptors on **vagal afferent nerve terminals**, sending emetogenic signals to the brain. Dolasetron blocks this interaction. * **Central Pathway**: Dolasetron also blocks 5-HT3 receptors located directly within the **Chemoreceptor Trigger Zone (CRTZ)** in the central nervous system. Once administered, dolasetron is rapidly converted by carbonyl reductase into its active metabolite, **hydrodolasetron**, which is primarily responsible for the pharmacological effects.
各物種劑量
- Anti-emetic, particularly for patients receiving chemotherapeutics · 0.6 mg/kg IV once daily · IV · q24h
- Vomiting disorders · 0.6-1 mg/kg PO q12h · PO · q12h
- Prevent vomiting · 0.6 mg/kg IV or PO once daily · IV/PO · q24h
- Treat vomiting · 1 mg/kg PO or IV once daily · PO/IV · q24h
- General anti-emetic · 0.6 mg/kg IV q12h or 0.6-1 mg/kg PO q12h · IV/PO · q12h
- Anti-emetic, particularly for patients receiving chemotherapeutics · 0.6 mg/kg IV once daily · IV · q24h
- General anti-emetic · 0.6 mg/kg IV q24h or 0.5 mg/kg PO, SC or IV q24h · IV/PO/SC · q24h
- Vomiting disorders · 0.6-1 mg/kg PO q12h · PO · q12h
- Prevent vomiting · 0.6 mg/kg IV or PO once daily · IV/PO · q24h
- Treat vomiting · 1 mg/kg PO or IV once daily · PO/IV · q24h
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
- Known hypersensitivity to dolasetron
- Atrioventricular (AV) block II to III
- Markedly prolonged QTc interval
不良反應
- Dose-related ECG interval prolongation (PR, QTc, JT prolongation, and QRS widening)
- Headache (reported in humans)
- Dizziness (reported in humans)
藥物相互作用
- Atenolol · May reduce the clearance and increase blood levels of hydrodolasetron
- Cimetidine · May reduce the clearance and increase blood levels of hydrodolasetron
- Ketoconazole · May reduce the clearance and increase blood levels of hydrodolasetron
- Phenobarbital · Can reduce hydrodolasetron blood levels
- Rifampin · Can reduce hydrodolasetron blood levels
監測
- Efficacy (resolution of nausea and vomiting)
- Heart rhythm (ECG) in at-risk patients (e.g., those with electrolyte imbalances or on arrhythmogenic drugs)
過量
Data on overdosage is very limited. * **Clinical Signs**: In humans, a massive overdose (13 mg/kg) resulted in severe hypotension and dizziness. * **Treatment**: Manage overdoses with supportive therapy, including IV fluids and pressors if hypotension occurs. * **Toxicity**: Lethal intravenous doses in mice and rats were 160 mg/kg and 140 mg/kg, respectively.
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。