I got sun poison while taking 6mp(Purinethol) and I had sun block on. =( I was in the sun for about
6 hours and applied sundblock continuously as it says but I still got burned badly on my back and shoulders. It made me feel horrible all over, after a visit to my doctor he said that I had sun poison. It was a long 2 weeks without a shirt on. I was 17 at the time. Please be very careful on this medication in the sun.