Can stopping Toprol cause palpitations? Or is it thyroid?

About two years ago, I noticed my heart was racing and I was having heart palpitations that felt like a hard or skipped heartbeat. I learned I was hyperthyroid and had Grave's disease. I was put on Toprol 25 mg daily to hekp with my heart while I went on an anti-thyroid called PTU.

Several months ago, palpitations began appearing again. I got tests done it appeared my thyroid was not overproducing anymore. Once I reduced my antithyroid to compensate, the palpitations went away.

A few weeks ago, following the numbers from blood test results, I went off PTU completely. Blood work showed my thyroid levels were normal and I didn't need PTU anymore. As I went off PTU, I went off Toprol as well. (I took it every other day for a week and then stopped.)

Then, about a week ago, I noticed I was having palpitations again that felt like fluttering. So about 3 days ago, I thought maybe I should go back on Toprol and began taking a half pill every night. Today in particular, I've been having a lot of flutters.

Is it possible that going off Toprol after my heart had been used to it is what's causing these flutterings? Or, is it possible that maybe I still need the Toprol for my heart and that's why I've been getting palpitations agin? Or could it be unrelated to the Toprol and my thyroid is acting up again? I'm going to see my doctor this week so I can request blood work, but I want to know if it's wrong that I have decided to put myself back on the Toprol.

I've read that heart flutters are usually benign, but it's hard not to feel concerned about it.

[Jerry_NJ]

My advice is not to use prescription medications unless advised to do so by your doctor.  The fact that you have some left-over meds doesn't mean it is ok to start them at some later date.  

I doubt that going off of Toprol would cause palps...  it is a beta blocker and while it does slow down electrical signals, its main purpose is to lower HR and BP, not control other heart rhythm symptoms.  That is what I understand.

[joelamp]

Going off Toprol can cause palpitations, yes.  It is a beta-blocker and, so, has the exact opposite effect of beta-agonists, such as adrenaline/epinephrine, isoproterenol, etc..  

Beta-agonists are heart stimulants and cause the heart to beat more rapidly and more forcefully and also make the heart more "irritable".