The use of Ribavirin to treat chronic hepatitis C in patients receiving azathioprine has been reported to induce severe pancytopenia and may increase the risk of azathioprine-related myelotoxicity. Inosine monophosphate dehydrogenase (IMDH) is required for one of the metabolic pathways of azathioprine.
There are several common underlying causes of kidney disease. 1  In older cats Interstitial Nephritis is most frequently seen. 2  Polycystic Kidney Disease (PKD) is a very common problem in Persian cats - 20-30% of them can be affected. 3  Tumours are occasionally seen in middle-aged and older cats.
Hyperthyroidism is relatively common in older cats. It is caused by a tumour, which in most cases is benign (non-cancerous). It can cause a lot of problems, including heart problems, so it is essential to treat it if present. There are a number of possible treatments, all with pros and cons. Once the hyperthyroidism is under control, CKD may be revealed (or, if already present, may appear to worsen) as true kidney function is revealed.