Help me find movie where person injects himself with serum and becomes unkill-able. I am not sure but If I remember correctly antagonist and protagonist start of as friends..

Help me find movie where person injects himself with serum and becomes unkill-able. I am not sure but If I remember correctly antagonist and protagonist start of as friends. Dude gets killed many times and he keeps coming back. At end hero himself injects serum in his body and chops the others dude. There is also a love-triangle involving a female. In one scene dude is thrown of a cliff while driving truck and he somehow comes back. Some details here might be incorrect I saw this movie when I was very young.