I just got up out of the chair and went to go outside and get my mail out of the lock box. My blood pressure seemed to drop and I couldn't get control of where I was walking, I finally fell in the parking strip of my home. Once I got back up I was fine. I normally have a blood pressure of 90/62 or there abouts. What drugs could cause this. My dr. at one time cut back, way back on the Serotonin I took thinking it was Serotonin Syndrome. I also take Plaquenil for Rhematoid Arthritis, Lipitor, daily vitamins. Before I went outside I had been sitting down playing solitaire on my tablet. I am 63 years old and 5'6 and weigh 150 lbs.