How do topical lidocaine patches function and in what clinical scenario are they most appropriately used?

• A. Local anesthetic effect via sodium channel blockade in cutaneous nerves; best for localized neuropathic pain such as postherpetic neuralgia or localized nerve entrapment
• B. Systemic analgesic effect for widespread pain
• C. Blockade of NMDA receptors
• D. Defunctionalization of central pain pathways

Answer: (A)