According to information on the Internet “Nefrosave” is a tablet that is available over-the-counter and not as a prescription. It is a combination of n-acetylcysteine and taurine. I am unaware of any studies that have examined this particular drug in patients with chronic kidney disease (CKD). N-acetylcysteine is commonly used to protect kidneys from injury with contrast dye used in radiology, vascular surgery and cardiology. I have no experience with this drug. I suggest that you contact your mother’s nephrologist for further advice.