<prompt> All of the following statements about sodium fluoride in otosclerosis are true, except:Acts by inhibiting Proteolytic enzymes in cochleaActs by inhibiting osteoblastic activityIs contraindicated in chronic nephritisIs indicated in patients with a positive Schwaze sign  <response>: In active cases i.e. when Schwaze sign is present, medical management with sodium fluoride Na F is done. Na F accelerates the maturation of the focus by increasing osteoblastic and decreasing osteoclastic activity. It also inhibits the proteolytic enzymes that release cytotoxic chemicals to cochlea. 