MichaelB,
Thanks for your question. You are presently on 5 different classes of medication for your blood pressure and it's not working at this time. Even without knowing the doses of these medications, it's time to step back and re-evaluate the situation.
Did your physician look for causes of your high blood pressure (hypertension)? Though the majority of people with hypertension have no identifiable cause, called essential hypertension, some patients do have a reason for their elevated pressure, which is then known as secondary hypertension. Your doctor needs to do a thorough search which ranges from blood tests, urine studies, Chest X-ray to more specified tests to evaluate your kidneys and their blood supplies. Perhaps it is time to see a specialist, and I would recommend a nephrologist (kidney specialist) who is also is an expert in diagnosing and treating hypertension. If your high blood pressure is secondary, then you need to have the cause corrected. If there is no cause, then he'll be able to get your pressure under control, after which he'll turn your care back over to your primary care physician.
I hope this has been helpful. Best wishes.
Martin Cane, M.D.