Beware of this Common Antihistamine
The Drug diphenhydramine, sold as Benadryl, and also an ingredients in Excedrin PM, Nytol, Sleep-Eze, Sominex, Tylenol PM and Unisom, has been shown to cause altered attention levels, disorganized speech, changes in consciousness and alertness, behavioral disturbances and dizziness in people age 70 and older. It may also cause urinary retention, which can lead to urinary tract infections.
Diphenhydramine acts by blocking the neurotransmitter acetylcholine. If you notice these adverse effects while taking diphenhydramine, ask your doctor about other, safer medications or alternative treatments.