55.下列有關EMLA（Eutectic Mixture of a Local Anesthetic）軟膏之敘述，何者錯誤？
(A)含2.5% lidocaine及2.5% prilocaine
(B)適用於表皮
(C)適用於黏膜
(D)可能產生變性血紅蛋白血症（methemoglobinemia）之毒性

Foye's 7E p.471

含有prilocaine的EMLA乳膏不建議用在黏膜，因為藥物經黏膜吸收快，可能會增加全身性毒性（例如：變性血紅素血症）的風險。

原文摘錄：...The use of EMLA creams, especially those containing prilocaine, on mucous membranes is not recommended, however, because of the faster absorption of the drugs and, therefore, the increasing risk of systemic toxicity, such as methemoglobinemia, specifically with prilocaine.

變性血紅蛋白血症 用甲基藍(methylene blue)治療

補充藥劑:

Benzalkonium chloride、亞甲基藍(methyl blue)為陽離子界面活性劑

肥皂、SLS、膽鹽、橘色二號、紅色二號為陰離子界面活性劑

剛果紅、Dodecyl-beta-alanine為兩性界面活性劑

Span(w/o)、Tween(o/w)為非離子性界面活性劑

Basic & Clinical Pharmacology 14th Edition

CHAPTER 26 Local Anesthetics P.471

PRILOCAINE

Prilocaine has the highest clearance of the amino-amide anesthetics, imparting reduced risk of systemic toxicity. Unfortunately, this is somewhat offset by its propensity to induce methemoglobinemia, which results from accumulation of one of its metabolites, ortho-toluidine, an oxidizing agent.

ELMA

The term eutectic is applied to mixtures in which the combination of elements has a lower melting temperature than its component elements. Lidocaine and prilocaine can combine to form such a mixture, which is marketed as EMLA (Eutectic Mixture of Local Anesthetics). This formulation, containing 2.5% lidocaine and 2.5% prilocaine, permits anesthetic penetration of the keratinized layer of skin, producing localized numbness. It is commonly used in pediatrics to anesthetize the skin prior to venipuncture for intravenous catheter placement.