皮內注射neostigmine沒有局部麻醉之作用

Intradermal Injection of Neostigmine has no Local Analgesic Effect

背景：以靜脈留置1分鐘，0.5 mg neostigmine （1 ml）是有一些周邊止痛之作用可減少propofol注射痛，但比lidocaine 20 mg的周邊止痛作用還少。至於此種週邊作用之機轉，文獻從未提及。 方法：以雙盲之方式，我們在十位自願者之前臂皮膚內注射0.5西西neostigmine 0.25 毫克，0.5西西lidocaine 5毫克，及生理鹽水0.5西西，注射痛與其局部麻醉之程度 （針刺，輕觸，冷覺）予以定時測量。 結果：0.05% neostigmine和生理鹽水一樣，在皮膚內注射時，沒有降低針剌，輕觸，冷覺之作用（p<0.01）。 結論：在皮膚內注射neostigmine和normal saline—樣，沒有局部麻醉之作用。

Neostigmine demonstrated systemic (1), central (2-4) or peripheral (5-7) analgesic effect. The clinical use of the systemically and centrally applied neostigmine is limited by side effects such as bradycardia or nausea/vomiting. The clinical use of its peripheral applications is not well known although peripheral analgesic effects were reported (6, 7, 8). We therefore undertook the following controlled study to elucidate whether neostigmine processes a local anesthetic effect. Equal volume (0.5 ml) of neostigmine 0.25 mg, lidocaine 5 mg and normal saline was injected to 10 volunteers. A 4-point sensory discrimination scores were used for the assessment of pain, touch and cold. The pH value of each drug was measured with a pH meter. We found than commercially available neostigmine produces no local anesthetic effect after intradermal injection, similar to that produced by normal saline.