I have been on toprol for four months. After a stent was put in my heart, I had very hard time adjusting and developed panic attacks and added xanax to the mix. After two month I had to stop taking Zocar because side effects. Still I was always exusted, mini black out spells, light headed during exercise, cold hands, no tolerance to cold weather, palpatations and memory loss. One day I was looking foe my cell phone in the office for ten minutes before I realized that I was talking on it. I was always leaving things behind and had to check I had everything I needed. But I knew things were not right when my BP range was 110/98 over 68-60 with a pulse of 56 to 39. I believe it is called bradycardia. Needless to say my doctor took me off the Toprol and the Zocar. After one day there is a 100% difference. I needed to do this months ago.