Lunox can help you drift off into a restful sleep and can help with temporary sleep disturbance. Contains the antihistamine diphenhydramine hydrochloride which induces drowsiness or sedation helping to aid sleep. Lunox Sleep Aid 25mg contains the active substance diphenhydramine hydrochloride which is an antihistamine with sedative properties which induces drowsiness or sedation. It works by reducing the time needed to fall asleep and increases the depth and quality of sleep. This medicine is used to aid relief of temporary sleep disturbance (difficulties sleeping) in adults and children over 16 years of age.