I Am Having High Blood Pressure, Was Already On Co-star

I am having high blood pressure, was already on co-star and htz for b/p. Doctor has given me hydralizine 10 mg, started with 10mg, then up to 15 mg now I've started 30 mg, twice a day! My b/p was 172/87 p 65 upon rising, now after taking 1 1/2 hours later is 146/72 p 73. This was given to me Nov 28