I am 5'5 and obese at 255. I used to take phentermine 20 years ago for short periods of time. The only side effects I experienced was dry mouth and occasional insomnia. I was diagnosed with hypertension 12 years ago which according to my physicians over the years is weight related. I am now on Benicar 20 mgs and was looking to take phentermine again. Will there be an interaction if I do this?