What is the difference between zyrtec and Claritin (loratadine) medicines?

Yes . Similarity: in the 2nd generation antihistamine class of drugs. Zyrtec and Claritin (loratadine) are safe in pregnancy. Both can cause dryness and urinary symptoms as a sideffect differences: Claritin (loratadine) does not usually cause drowsiness. Zyrtec typically can. The time it takes to be effective vary as well. As far as effectiveness: depends on person. Zyrtec in some studies have been shown to be faster acting.
Both antihistamines. Zyrtec and Claritin (loratadine) are both antihistamines. Imho, zyrtec works better but has a small chance of making you sleepy.