I tried twice to go cold turkey with selo-zok
(also a betablocker). my dose was 25mg x 2.
I wouldn't recommend that... My heart was jumping, loads of pvc, extreme headache for 2 days. cutting a pill in half sound like a good idea. I think that you may need weeks to wean the metroprolol off.
Strange the cardiologist didn't gave you some info when he said that you could stop taking this, but anyways, get some advice from you doctor
good luck to you!