I have seasonal nasal allergies. Antihistamines make me drowsy, even the ones that aren't supposed to like allegra, claritan and zyrtec. I took a zyrtec yesterday and it knocked me out for 12 hours.
The reason these aren't supposed to make you drowsy is that they don't cross the blood brain barrier, or least not that much. So, I've been wondering if my immune system can attack my CNS for the same reason these antihistamines make me drowsy: CCSVI opened up my BBB.
If there's anything to this, then I should be able to tell if anything I do is helping heal my BBB over time by taking a zyrtec.
Nothing's ever this simple of course, but I thought it worth mentioning here. Does anyone else have this issue with the "non-drowsy" antihistamines?