Lidocaine + diphenhydramine

Lidocaine + diphenhydramine is a combination of two small molecule drugs commonly used topically or as part of compounded preparations to relieve pain and itching associated with inflammatory and allergic skin conditions, as well as oral mucositis. Lidocaine is an amide-type local anesthetic that works by blocking sodium channels on nerve cell membranes, thereby inhibiting the initiation and conduction of nerve impulses, resulting in local anesthesia. Diphenhydramine is a first-generation antihistamine that acts primarily as an antagonist at histamine H1 receptors, reducing symptoms such as pruritus (itching) caused by histamine release during allergic reactions. The combination provides synergistic effects for symptomatic relief in conditions like insect bites, contact dermatitis, jellyfish stings, and mouth sores[2][3][8]. Clinical studies support its efficacy for treating histamine-related skin reactions accompanied by pruritus[2]. The mixture may be found in topical gels or compounded oral rinses (e.g., "magic mouthwash") for mucosal pain management.