I'm starting to read about warnings for a class of drugs called "anticholinergies". They are used in a lot of different applications, including allergy meds. Apparently, because they can cross the blood-brain barrier, they can affect the brain. In this case, they have been linked to increased risk for dementia.

If your med makes you feel drowsy, you might want to be sure it doesn't contain that class of drug.

Wikipedia: Anticholinergic - Wikipedia(anticholinergic%20agents)%20are%20substances,its%20receptor%20in%20nerve%20cells.

scientificamerican.com - Does long term benadryl use increase dementia risk

This board isn't very active. If no one is reading here, I can move it to Atheist or Policy. Atheist is sort of a free-for-all anyway, and I can angle this towards US policy (e.g. "why the heck are they allowing that medication to be sold?!").