I am 57 yrs old and use to be a meth head several years ago. Having a CLD and new work testing policy i gave it up. I take Warfarin because of my heart problem. I have my INR checked monthly. My INR usually stays pretty constant. My last blood test showed my blood thinner than it has been. Can smoking meth causing my blood to be thin and with the med cause it to be thinner. I know the other dangers of smoking meth. A friend was around for about a month and a half and he had some almost daily. I wasn t high the whole time but it was more than I had had in some time. He has since left town and I don t have access to it any more.