Suddenly High BP - especially Diastolic

Hi,

I am taking 10 mg enalapril twice a day - 46 years old, generally healthy, nonsmoker, 150 lbs and 5 ft 4 in.  I was surprised last year that my blood pressure was getting very high at night (sometimes as high as 170/112 but usually 140/95 or so).  I saw a cardiologist who put me on meds, said it is family history.

The odd thing is that my BP spikes every night between 7P-10P and then goes down.  During the day it is usually fairly normal.  I am usually reading, watching TV, etc. during that time so no stress at all (and no kids!).  We thought it was under control with the Enalapril although I've always wondered why no one seems to know the reason for it spiking just during those hours??

In the last few days it has been ranging from 150/102 last night to 120/99 right now (mid afternoon).  I'm quite concerned by this sudden spike, can that hurt me?  Could I double up on my meds?  Just wondering what might cause that.

If you have any information that can assist me I would appreciate it!

Thank you,

Laurie