HTCZ was prescribe for me about a year ago with Lotension. I too had problems-Headache /heart palps / and head felt so heavy I felt like I was going to pass out. Couldn't sit up for longer than hour! Dr didn't think it was the HTCZ changed the Lotensin to Benicar. Still same symptoms-finally too the HTCZ away and no more problems. Dr thought might be sensitive to sulfa drugs which HTCZ has. I also was ordered a CT scan any everything came out fine.