You will take GSK2118436 capsules by mouth for 28 straight days. If your Day 28 whole body radioactive iodine scan demonstrates significant uptake of iodine, you will take GSK2118436 for an additional 14 days (Days 29-42). You will be given a drug diary to record when you take GSK2118436. This diary will also contain instructions on how to take GSK2118436.