Plain English Meaning

A common allergy and sleep medicine that makes you drowsy and mentally slow. Pilots are not allowed to fly while it is still in their system.

Full Definition

Benadryl is a brand name for the over-the-counter antihistamine medication diphenhydramine, used to treat allergy symptoms, hay fever, cold symptoms, and as a sleep aid. It causes significant drowsiness, impaired coordination, slowed reaction time, and reduced alertness, and is on the FAA's list of medications that are disqualifying for flight.

Context Anchor

Seen in aeromedical and preflight fitness discussions, especially when reviewing drugs that can affect a pilot’s ability to fly safely.

Derivation

Benadryl is a trademarked drug name, not a word whose parts explain its meaning. The important for pilots is that the brand name contains the active drug diphenhydramine, which is known for causing drowsiness in many people.