title: Efficacy and tolerability of conversion from cyclosporin to azathioprine after kidney transplantation: a review of the evidence.
abstract: After the introduction of cyclosporin as an immunosuppressive drug for organ transplantation at the beginning of the 1980s, concern arose about adverse effects of this new drug. Nephrotoxicity, fear of progressive loss of renal function with long term use of cyclosporin, a higher incidence of lymphomas in the first studies with cyclosporin and the high costs of the new drug led to the modification of immunosuppressive regimens so that cyclosporin was replaced by azathioprine several months after renal transplantation. Short and long term follow-up of elective conversion studies demonstrated equal patient and graft survival in the azathioprine (conversion) and cyclosporin (control) groups. Shortly after conversion, renal function improved considerably and a decrease was found in the number of patients with hypertension and gout. Conversion also resulted in a substantial reduction in the costs of immunosuppressive drugs. In most studies a higher incidence of acute rejection was found after conversion. These rejection episodes were generally reversible and at long term follow-up did not result in a higher incidence of chronic rejection or graft loss. Elective conversion from cyclosporin to azathioprine after kidney transplantation can be done safely and has beneficial effects on renal function and cardiovascular risk factors. Conversion should also be considered for patients with prolonged non-function of the graft, in cyclosporin-treated patients with substantial renal or neurological toxicity persisting after cyclosporin dosage reduction, and in patients who cannot afford the high costs of cyclosporin therapy.
authors.affiliation: Department of Nephrology and Transplantation, University Hospital, Leiden, The Netherlands.
authors.forename: A A
authors.initials: AA
authors.lastname: Hollander
authors.forename: F J
authors.initials: FJ
authors.lastname: van der Woude