Hi me agin, for the past two weeks since I came home from hospital my INR has been 2.5 and so I was 2.5 a few days and then 3mg for two days. When I went back this week it was 1.7 again. The day before I was out with my grandson shopping for quite a few hours here there and everywhere. Could this have caused my drop? Also can anyone tell me if the sun affects the way warfarin acts, as I am a Leo and love to sit in the sun. I do not know what i will do if this is so. At 72 years of sunshine it will be like telling me to stop breathing.