The FDA recently called to phase out phenylephrine, a common nasal decongestant found in hundreds of over-the-counter medications including DayQuil, Sudafed, Dimetapp, and Benadryl. U.S. officials have long questioned the effectiveness of oral phenylephrine claiming that it does not successfully relieve nasal congestion and should be removed or reformulated by drug manufacturers. The FDA’s move comes after federal advisers voted unanimously in 2023 that there was no evidence to support that phenylephrine relieves congestion in oral medications. The reasoning is that oral medications that include phenylephrine are no longer effective once they hit the stomach. Acids in the gut deactivate the decongestant making it ineffective once it reaches the bloodstream and the nose. Learn more about decongestants.