M58, may i take zyrtec (cetirizine) 1 tab with norvasc 5mg for long time. any drug interaction?

Yes: No problem, there are no known interactions. (also, I personally have been taking Zyrtec (cetirizine) for at least 10 years and prior to that, some kind of anti-histamine for 40 years - without harm).

Check it out: You can use a drug interaction checker whenever you have questions about drug-drug interactions or drug - food interactions. Here is 1 option (Drugs.Com): https://www.drugs.com/drug_interactions.php Your pharmacist is also a good source of info.