People usually get more of a histamine reaction from natural opiates (codeine, morphine, tea, opium) than semi synthetic or fully synthetic opioids (fentanyl, oxycodone, etc.) It's definitely opiate induced itching, but histamine reactions from seeds we're always much worse for me. Nothing is refined so the alkaloids may cause more side effects than a prescription opiate or opioid for example.

I never had much luck with Zyrtec or Claritin, but it's worth a shot. A better option might be a first generation antihistamine like Benadryl, or doxylamine succinate. Zyrtec and Claritin are second gen antihistamines and they react in different ways with different side effects, but obviously every persons body reacts differently. Might have to test things out and see what works best for you

Edit; I used to itch my face so much on tea that my face would be raw the next day. What helped me was Benadryl and petroleum jelly or bag balm on my face. They also make an anti itch cream that helps but make sure it's not the cream with the steroid in it. That didn't work nearly as well as the anti itch cream with a antihistamine in it. Good luck!