Lidocaine 5% w/w is a topical local anesthetic used to provide short-term numbness and relief of localized pain and itch on skin or mucous membranes, including indications such as post‑herpetic neuralgia patches and oropharyngeal anesthesia formulations. It works by blocking voltage‑gated sodium channels in peripheral nerves, stabilizing neuronal membranes to prevent action potential initiation and transmission, thus reducing pain signaling. Typical 5% systems include ointments and transdermal patches that deliver local analgesia with minimal systemic exposure when used appropriately in intact skin scenarios.