Can I cut a lisinopril tablet in half, or is it one that's not supposed to be cut?

I am prescribed 5mg lisinopril. By my cardiologist who is very reputable on the mainland of northwestern Washington. I called him and told him that when my systolic no was above 130 and I took the med it would drop it more often than not to 89 systolic. He told me to cut it in half and only take it if my static was > than 100 and I was feeling NO signs of low no. I have felt much better. If you pm me on FB I am willing to give you his name. I hope this helps.
Cynthia Smith
OAK harbor, washington