Is It Possible For BP To Be 90/66 While On Diovan 160mg?

my wife has always had high to borderline high blood pressure and she currently takes medication, Diavon 160mg. She checked her pressure today and it was 90/66. Is the machine broken or is this possible. Her heart rate was 55. I checked my BP and it was 102/68 and HR was 56. She is slightly overweight. Thanks