Hello and Welcome to ‘Ask A Doctor’ service. I have reviewed your query and here is my advice. Well there is no direct relationship between neomercazole and renal failure, but there is indirect relation here. Your uncle was taking neomercazole for hyperthyroidism and at that time kidney functions tests were normal but now he has stopped taking it so his hyperthyroidism has worsened and hyperthyroidism (elevated thyroid hormone in body) causes almost every organ of the body to hyperfunction which in this case has caused excessive stress onn the kidney which has led to the increase in level of creatinine and urea. Another point which i would like to highlight here is that your uncle is also type 1 diabetic is his diabetes well controlled? If not then this is also a silent killer as it might have damaged the kidneys and kidney. Hope I have answered your query. Let me know if I can assist you further.