I am 70 years old with ET and MPL mutation. I have been on Hydroxyurea since June of last year when my platelets were about 900. My dosage keeps being adjusted, even now, because my blood work keeps changing….i would get close to being good with platelets nearing 400, but then my white blood cells would drop so much that I would have to cut back on the Hydroxyurea. Last month my white blood cells had been stable for a couple of months but my platelets were climbing so I once again had my dosage increased to 500 mg 5 days a week and 1000 mg the other 2 days. I have just recently had another blood test but my platelets are still 657 and white cells are within the normal range. But what has me concerned now is that my Creatinine level has entered into the dangerous zone with 86 and my eGFR is 59…..both of which indicate kidney disease. I don’t see my haematologist until April, but have an appointment with my family doctor in January, so I will be asking her then if I should be concerned. I never had any issues with these prior to taking Hydroxyurea…..has anyone else experienced this side effect?