Which of the following is a topical analgesic used for neuralgia?

Lidocaine is a topical analgesic that is commonly used to alleviate pain associated with conditions like neuralgia. It works by blocking sodium channels in nerve cells, which prevents the generation and transmission of pain signals to the brain. When applied to the skin, Lidocaine numbs the area and provides temporary relief from pain, making it effective for localized neuralgic pain.

Other options listed serve different purposes. Hydroxyzine Hydrochloride is primarily an antihistamine used for allergies and anxiety, not for pain relief. Trimethoprim and Sulfamethoxazole are antibiotics used to treat bacterial infections and do not possess analgesic properties. Therefore, Lidocaine stands out as the correct choice due to its specific mechanism of action targeting nerve pain.