Diltiazem
"I have been taking Diltiazem 360 mg once a day for about 10 years along with 20 mg per day of Lisinopril for high blood pressure.  I am 58 years old. This combination has kept me at normal BP numbers all these years. The Diltiazem capsules are 180 mg each so obviously I have to take 2 capsules (at the same time). I have noticed in the last few months my BP gets pretty low...about 90/60 and even lower. Every time I bend over I get real lightheaded not to mention feeling tired all the time so I decided to take just one capsule per day of the diltiazem along with the Lisinopril and in the last 3 days of doing so I feel 100% better! I think the 360mg is too much for me now maybe because I am getting older. My BP now stays about 117/73."