ST LOUIS (MD Consult) - The US Food and Drug Administration (FDA) has issued a Public Health Advisory to alert consumers, patients, health care professionals, and caregivers about potentially serious and life-threatening risks from the improper use of skin numbing products.

The products, also known as topical anesthetics, are available in over-the-counter (OTC) and prescription forms.

Skin numbing products are used to desensitize nerve endings that lie near the surface of the skin, causing a numbness of the skin. These topical anesthetics contain anesthetic drugs such as lidocaine, tetracaine, benzocaine, and prilocaine in a cream, ointment, or gel. When applied to the skin surface, they can be absorbed into the blood stream and, if used improperly, may cause life-threatening problems such as irregular heartbeat, seizures, breathing difficulties, coma, or even death.

The FDA has received reports of adverse events and deaths of 2 women who used topical anesthetics before laser hair removal. In February 2007, the FDA issued a Public Health Advisory—Life-Threatening Side Effects with the Use of Skin Products Containing Numbing Ingredients for Cosmetic Procedures—to warn consumers about these products.

Patients for whom an OTC or prescription topical anesthetic is recommended should consider using a product that will relieve the pain with the lowest amount of medication possible. Also, health care professionals should determine whether adequate pain relief can be safely achieved with a topical anesthetic, or if a different treatment would be more appropriate.

The FDA strongly advises consumers not to:

• Make heavy application of topical anesthetic products over large areas of skin;
  
   
• Use formulations that are stronger or more concentrated than necessary;
  
   
• Apply these products to irritated or broken skin;
  
   
• Wrap the treated skin with plastic wrap or other dressings; and
  
   
• Apply heat from a heating pad to skin treated with these products.
  
   

When skin temperature increases, the amount of anesthetic reaching the blood stream is unpredictable, and the risk of life-threatening problems increases with greater amounts of lidocaine in the blood.

A recently published study in Radiology looked at women taking acetaminophen and ibuprofen by mouth versus applying lidocaine gel, a topical anesthetic, to the skin to decrease discomfort during mammography. The lidocaine gel was applied to a wide skin-surface area and then covered with plastic wrap. There were no serious or life-threatening effects reported in the study, nor were any reported when the FDA discussed the results with the doctor who performed the study. The study results favored the use of lidocaine as there was significantly less discomfort than with the plain gel or oral acetaminophen or ibuprofen.

However, given the life-threatening effects associated with using topical anesthetics during laser hair removal, the FDA is concerned that similar adverse effects could occur when topical anesthetics are used during mammography. Further, the study was small and it is possible a larger study might show different findings.

Patients considering using a topical anesthetic before a mammogram should talk with their health care professional. The following summarizes advice for patients if a topical anesthetic is recommended for their use:

 

• Use a topical anesthetic with the lowest strength, and amount, of medication that will relieve the pain;
  
   
• Apply the topical anesthetic sparingly and only to the area where pain exists or is expected to occur;
  
   
• Don't apply the topical anesthetic to broken or irritated skin;
  
   
• Ask the health care professional what side effects are possible and how to lower the chance of having life-threatening effects from anesthetic drugs; and
  
   
• Be aware that wrapping or covering the skin treated with topical anesthetics with any type of material or dressing can increase the chance of serious adverse effects, as can applying heat to the treated area while the medication is still present.
  
   

Consumers and health care professionals may report adverse events to the FDA's MedWatch program at 800-FDA-1088, by mail at MedWatch, HF-2, FDA, 5600 Fishers Lane, Rockville, MD 20852-9787, or online at www.fda.gov/medwatch/report.htm. To read the FDA's 2009 Public Health Advisory, go to: www.fda.gov/cder/drug/advisory/topical_anesthetics2009.htm.
 

圣路易斯（MD Consult）——美国食品与药物管理局（FDA）发布了一项公众健康忠告，提醒消费者、患者、医生和护理人员，皮肤麻醉产品使用不当会带来严重甚至致命危险。

皮肤麻醉产品也称表面麻醉剂，有非处方（OTC）类和处方类两种。

皮肤麻醉产品用于麻醉皮肤表面下的神经末梢，从而造成皮肤麻木。该类产品为含有利多卡因、丁卡因、苯佐卡因和丙胺卡因等麻醉药的乳膏、油膏或凝胶等。表面麻醉剂涂抹于皮肤表面时可被吸收进入血液循环，如果使用不当会引起致命危险，例如心律不齐、癫痫发作、呼吸困难、昏迷甚至死亡。

FDA已经收到2例女性在接受激光脱毛术前应用表面麻醉剂发生不良事件和死亡的报告。FDA在2007年2月曾经发布过一项公众健康忠告——含有麻醉剂成分的皮肤产品用于美容手术时可能会引起致命副作用—以警告消费者关于此类产品的应用风险。

使用OTC类或处方类表面麻醉剂的患者应考虑使用能够缓解疼痛的最低药物剂量。同样，医生也应明确使用表面麻醉剂是否可以安全地达到充分的止痛作用，或如果采取其他治疗方法是不是更恰当。

FDA强烈建议消费者不应：

• 在大面积皮肤涂抹过量表面麻醉剂产品；
• 使用强度或浓度超过需要的制剂；
• 将这些产品涂抹于易过敏或破损皮肤；
• 用塑料膜或其他敷料包裹治疗部位皮肤；以及
• 在这些产品治疗的皮肤部位使用加热垫进行热疗

当皮肤温度升高时，无法预测麻醉药物进入血液循环的药量，而发生致命问题的风险随血液中利多卡因药量的增加而增加。

一项最近发表在《放射学》杂志的研究对比观察了女性在乳腺X线检查期间采用口服扑热息痛和布洛芬与采用表面麻醉剂利多卡因凝胶涂抹皮肤以缓解疼痛不适的效果和安全性。在大面积皮肤表面涂抹利多卡因凝胶后，以塑料膜覆盖。该研究无严重或致命副作用出现；FDA与进行该研究的医生讨论研究结果时也没有关于此类副作用的报告。该研究结果支持使用利多卡因，因为利多卡因凝胶与一般凝胶或口服对乙酰氨基酚（扑热息痛）和布洛芬相比能够更显著地减少患者不适。

然而，考虑到激光脱毛术时与应用表面麻醉剂相关的致命副作用，FDA担心在乳腺X线检查期间应用表面麻醉剂也会发生类似的不良反应。此外，上述研究的样本量较小，如果样本量再大些，或许会有不同的结果。

在乳腺X线检查前考虑应用表面麻醉剂的患者应咨询医生。以下是针对需要应用表面麻醉剂的患者的建议：

• 应用表面麻醉剂时选择能够缓解疼痛的最低强度和最低药量；
• 保守应用表面麻醉剂，仅涂抹于存在疼痛或可能发生疼痛的部位；
• 不要将表面麻醉剂涂抹于破损或敏感皮肤；
• 使用前向医生咨询表面麻醉剂可能引起的副作用，并了解如何减少致命副作用的发生；以及
• 需要注意的是，以任何类型的材料或敷料包裹或覆盖表面麻醉剂治疗的皮肤部位，会增加发生严重不良反应的风险；同样，在皮肤上仍有药物时对治疗部位进行热疗，也会增加发生严重不良反应的风险。

消费者和医生可将不良事件上报至FDA MedWatch系统。电话：800-FDA-1088；邮件：MedWatch, HF-2, FDA, 5600 Fishers Lane, Rockville, MD 20852-9787；或在线提交至：www.fda.gov/medwatch/report.htm. 如需阅读FDA2009年公共健康忠告，请点击：www.fda.gov/cder/drug/advisory/topical_anesthetics2009.htm.

爱思唯尔 版权所有