Sometimes just a diuretic and postassium supplements can help, but better is a proper diet. However, if medication is prescribed it is an ACE inhibitor. This medicaion prohibits the kidneys fro producing angiotension. Angiotension is hormone that suppresses as a vasoconstrictor. Or there can be ARB and that lowers blood pressure by binding angiotensin to a receptor. Either can be effective and the combination of the two can be an option as well.
What meds have you tried. I'm not into pharmacology so I don't know if one brand of an ACE inhibitor or ARB brand is superior to another and may require trial and error procedure to find the right does and medication. Also, the medciation may take longer than expected to become effective!
Hope this helps, and thanks for the question. Take care,
Ken