The progressive renal failure of a 49-year-old female diabetic patient with renal insufficiency and hypothyroidism was successfully prevented by levothyroxine sodium treatment. Her renal function worsened in parallel with the exacerbation of hypothyroidism. Cessation of progressive renal failure was observed after administration of levothyroxine sodium (0.05mg daily) for more than 24 months. Mean slopes of reciprocal serum creatinine levels for 12 months before and after the administration of levothyroxine sodium were -1.67×10^-3 and +8.68×10^-4, respectively. It was suggested that levothyroxine sodium was effective in the prevention of progressive renal failure in this patient.
(Internal Medicine 31 : 251-255, 1992)