high blood pressure
"Since being put on 6 months ago (severe, resistant hypertension), along with diet and exercise, I have lost 60 lbs and my heart rate is usually in the mid -40s to low 50s when and complete rest (evenings) and in the high 50s - low 60s during the day.  I have experienced no negative side effects.  Drowsiness was present for the first week or two, but after that I adjusted and feel no side effects. 

Most important thing - if you are doing aerobic exercise while on this medication, DO NOT USE A HEART MONITOR as it does reduce heart rate.  Normal heart rate ranges while on this medication to not apply and can cause damage if you attempt to the normal 180bpm.  Consult a physician for activity restrictions while taking Carvedilol."