List of products in the National Drug Code with proprietary name . This medication is used by people who have a certain inherited kidney problem (autosomal dominant polycystic kidney disease-ADPKD). This inherited kidney problem leads to the growth of fluid-filled sacs (cysts) in your kidneys. Over time, the cysts grow in size, which can damage the way your kidneys work and lead to kidney failure. Tolvaptan belongs to a class of drugs known as vasopressin receptor antagonists. It works by slowing the growth of kidney cysts caused by ADPKD. This effect helps protect your kidneys from damage and failure. Different brands of this medication have different uses. Do not change brands of this medication unless directed by your doctor.