I Went To The Doctors Yesterday And My Top Reading

i went to the doctors yesterday and my top reading of blood pressure was 168 and she put me straight on Ramipril 2.5mg does. I took a tablet yesterday afternoon and one again this morning. When I checked my blood pressure at 8.30 it was 115/59. Would it work that quickly? I actually went to the doctors thinking I had vertigo as I get dizzy in bed when turning over.