PVC's

I have been bothered with PVC's for over 5 years now.  I was put on medicine which helped for a while.  It seems that about 2 months before I'm due to go for my one year check up, they come back.  Is it possible that my body adjusts to the dosage I'm taking and that's why I have to keep increasing?  Right now, I'm taking 75 mg in the morning and 100 mg at night of toprol.  My next appointment with my cardiologist is Jan. 3 and over the phone they increased my night dosage to 100 mg till I can get there next month.  How much is safe?  I seem to be so tired all the time and I know it's because of the medicine.  Is there nothing else to be done?
thanks,
Nan

[CCF CARDIO MD - DLB]

The dose you are on is safe. Your body does not really become tolerant of the medication and I do not think that is why you have needed more medicine now than in the past. Beta blockers are the safest medicine for PVCs when treatment is deemed necessary. Any higher dose would probably just increase the fatigue more.