Cyclosporin A nephrotoxicity related to changes in haemoglobin concentration

Cyclosporin A is increasingly being used for patients undergoing bone marrow and solid organ grafting. Also preliminary results show that cyclosporin A may be of benefit in some autoimmune diseases, including primary biliary cirrhosis. Of the side effects of cyclosporin A, nephrotoxicity is the most common; this is largely dose dependent and reversible, and with careful monitoring of cyclosporin concentrations in blood or plasma the frequency of the complication may be reduced. We describe four patients with primary biliary cirrhosis receiving cyclosporin A in whom the development of nephrotoxicity was unexpected and shown to be related to a fall in haemoglobin concentration associated with a rise in plasma cyclosporin values.