This stuff is pure poison and should be pulled from the market. I am very healthy except for seasonal allergies. I started using this drug in early June this year and within a few days I was experiencing dizziness (which I attributed to the allergies), panic attacks, cardiac arrhythmia and shortness of breath. Twice I ended up in Emerg only to be told that all my vital signs were excellent.
Since I've stopped taking Zyrtec those side effects have diminished greatly, although they haven't gone away completely. It could take weeks for the body to rid itself of a poison.
This drug needs to be re-examined with better controls on the testing, and serious consideration should be given to removing it from the market. The FDA has been to hasty in approving dangerous drugs over the last few years and Zyrtec is just another example of this haste. Remove it before someone dies!