Do not take Thelin: • If you are allergic (hypersensitive) to sitaxentan sodium or any of the other ingredients in these tablets; • If you have or have had a serious liver problem; • If you have raised levels of some liver enzymes (detected by blood tests); • If you are taking Ciclosporin A (used to treat psoriasis and rheumatoid arthritis, and to prevent rejection of liver or kidney transplants); • If you are breast-feeding (please read the section ‘ Pregnancy and breast-feeding’ below); • If you are a child or adolescent under 18 years old.