I suffer from extreme blood pressure problems, how can I get my BP down?

I suffer from extreme blood pressure problems. I now have 198 over 72 but cannot get it down. I went to an ER and there they gave me a Nitroglycerin patch which helped reduce it to 180. Doctor prescribed Coversyl 5 – 2.5 but it doesn’t seem to work. I have had heart surgery with valve.

Male
Age: 52
Medications: Coversyl, Coumadin