Serious Use Alternative 1 crizotinib and eribulin both increase QTc interval priligy and viagra combination Individuals who are either homozygous or heterozygous for thiopurine methyltransferase TPMT deficiency are at risk of developing life threatening myelosuppression or severe hematopoietic toxicity when placed on standard doses of azathioprine Imuran, 6 mercaptopurine Purinethol, or 6 thioguanine Thioguanine Tabloid