What pill is round white 54 over 262?

The pill imprinted with "54 262" is identified as Diphenhydramine Hydrochloride 25 mg, which is an over-the-counter antihistamine commonly used to relieve symptoms of allergy, hay fever, and the common cold. It can help alleviate symptoms such as itching, runny nose, sneezing, and itching of the throat or nose. Diphenhydramine is also often used as a nighttime sleep aid due to its sedative properties. Always consult with a healthcare professional before using any medication.