Effexor and guanfacine

Want to know of any experiences with both of these meds. I've struggled for so long with anxiety and Effexor has finally helped me. I'm afraid to add on the guanfacine, I just want to make sure there won't be any weird reactions or what I should look out for. I used to take Vyvanse and it was great mostly but had to stop because I have high blood pressure.

Thank you in advance