Title: Case report: tolvaptan-associated creatine kinase elevation in two patients with autosomal dominant polycystic kidney disease (ADPKD)
Abstract: Autosomal dominant polycystic kidney disease (ADPKD) is a genetic disorder that leads to an abnormal polycystin protein, which causes hypertension and cysts in different organs.The goal in ADPKD is to postpone kidney damage; however, there are no specific treatments [1].Vasopressin antagonists decreased cAMP and cell proliferation in kidney epithelial cells and improved renal function in ADPKD-rodent models [2].Tolvaptan (Jinarc®, Otsuka Pharmaceutical, Japan), an oral vasopressin-antagonist used for SIADH, slowed cyst development in ADPKD patients during TEMPO 3:4 and 4:4 clinical trials; adverse events (AE) were polydipsia, headache, polyuria, and fatigue [3][4][5].It was approved for ADPKD in 2015 [6]; it is recommended to start treatment with 45 mg in the morning and 15 mg in the evening (45-0-15) and increase it according to tolerance.