Norvasc
"Within a few days of starting this medicine, I became very aware of my heart beat and my heart seemed to be racing.  I attended a pre-operative assessment where I was given a routine ECG and this confirmed that I had become tachycardic while taking amlodipine.  My pulse was racing at over 100 BPM and my blood pressure actually went UP while I was taking this medicine.  I had to discontinue use to stop the adverse effects."