Does anyone know the long term effects of zyrtec (cetirizine)?

Zyrtec (cetirizine) effects. Antihistamines in general are some of the safest medications to use long-term.That said, one should never use a medication longer than necessary, and it is wise to switch products periodically no matter what the medication class, in case you are having side effects but don't realize it.I have seen occasional patients develop what seem to be "rebound hives" after long-term use of antihistamines.