護理師正為一位癲癇病人靜脈注射苯妥英（Phenytoin）。下列哪項是此藥物給藥最重要的規則？
A nurse is administering Phenytoin (Dilantin) intravenously to a client with seizures. Which of the following is the most important administration rule for this medication?
- AAdminister the medication via a small-gauge peripheral needle通過小口徑周邊靜脈針給藥
- BShake the vial vigorously before drawing up the dose抽取劑量前劇烈搖晃安瓿瓶
- CFlush the line with D5W before and after administration給藥前後用D5W沖洗管路
- DAdminister at a rate no faster than 50 mg/min✓ 正解給藥速度不得快於50 mg/min
Phenytoin（苯妥英）是一種強力的抗癲癇藥物，其靜脈給藥極具風險。核心規則之一是輸注速度限制：成人不可超過 50 mg/min。若給藥太快，會導致嚴重的低血壓與心律不整。選項 C 是錯誤的，Phenytoin 只能與生理食鹽水（NS）相容，若接觸 D5W（葡萄糖水）會立即產生沉澱，堵塞血管。選項 A 錯誤，此藥對組織極具刺激性（Purple Glove Syndrome），應使用大口徑靜脈或中心導管。選項 B 錯誤，此藥不應劇烈搖晃，且通常為透明液體。臨床思路上，護理師必須確保：1. 僅用 NS 沖洗；2. 嚴格限速；3. 監測心電圖與血壓。這題考驗的是對高風險藥物物理性質與生理影響的精確掌握。
Phenytoin is a potent antiepileptic medication, and its intravenous administration carries considerable risk. One of the core rules is a strict infusion-rate limit: in adults, it must not exceed 50 mg/min. Administering it too rapidly can cause severe hypotension and cardiac dysrhythmias. Option C is incorrect because phenytoin is compatible only with normal saline (NS); contact with D5W (dextrose) immediately produces a precipitate that can block the vessel. Option A is incorrect because the medication is highly irritating to tissue (Purple Glove Syndrome) and should be given through a large-bore IV or a central catheter. Option B is incorrect because the drug should not be shaken vigorously and is normally a clear solution. The nurse must ensure: 1. flushing only with NS; 2. strict rate control; 3. monitoring of ECG and blood pressure. This question tests precise mastery of the physical properties and physiological effects of a high-risk medication.
美國 NCLEX 非常強調 50 mg/min 這個具體數值；台灣臨床實務中，靜脈注射 Phenytoin 較常改用 Fosphenytoin（磷苯妥英），因為後者穩定性更高、副作用較少，但在考試中，傳統 Phenytoin 的物理化學特性仍是核心考點。