CABG, Beta Blocker Rebound and Running?
Hi, new member here with my first post. I'm 57 years old, and had cabg x6 in March 2018. In 2017, I was running 5k's, then developed stable angina in February 2018. After my surgery, I was prescribed Crestor, Plavix, metoprolol tartarate (25 mg 2x/day), and low dose aspirin. In addition, I have been taking Wellbutrin for around 6 years for an unrelated condition. My concern is with the metoprolol and some adverse effects that I am having.
My recovery went very well, probably due to my overall physical condition. I started running again in April and noticed the following: substantial effort where rate of perceived exertion (RPE) was high, dizziness when standing, weight gain, bradycardia, hypotension, and winded when climbing hills and stairs. My cardiologist reduced my medication to 12.5 2x/day and some of the symptoms subsided. I also found that my runs were improved if I ran *before* taking the half-tablet. (RPE) was improved, heart rate increase slightly but would I would still struggle with longer runs.
After discussion with my cardiologist, he decided to have me stop taking the metoprolol since it was such a small dose. Three days later, my easy run pace improved by 1 minute/mile with a much improved RPE. However my heart rate was near my maximum. I also noticed irregular heart beat, my blood pressure was ca. 160/105, palpitations, feelings of anxiety. The concern that I have is whether or not the Wellbutrin caused the "low dose" metoprolol to have more of an effect on blood concentration, thus making the sudden stop in medication causing a rebound effect.
I discussed the interaction between metoprolol and Wellbutrin with my cardiologist and he seemed convinced that 12.5 mg 2x/day was a very small dosage and did not appear to be concerned with the rebound effect. If my heart rate is near maximum when running *easy*, then should I be concerned with running harder? Also, should I be following a tapering protocol? Any guidance would be helpful, and I do realize that before doing anything, I should consult my cardiologist or other health care provider.
Additional stats: male, 5'10", 148 lbs, thin/average frame. Not obese, not type 2 diabetic, history of high cholesterol w/ HDL >70. Family history of heart-related issues. Ejection fraction 55% prior to surgery.