Deterioration in renal function associated with fibrate therapy.

Background: Fibric acid derivatives (fibrates) are commonly used for the treatment of hyperlipidemia. A side-effect of these medications that is not well recognized is deterioration in renal function during therapy. This study reviewed a series of patients who showed such a deterioration.
Methods: The design was a retrospective chart review. Data extracted included creatinine, urea, cyclosporine levels, medical history, and medications. Charts were examined for other potential reasons for a change in creatinine.
Results: There were a total of 10 patients. All were males between the ages of 37 and 71. All had a history of renal insufficiency. Six had received a renal transplant and, of these, 5 were on cyclosporine. Reasons for underlying renal impairment included diabetes, hypertension, nephrosclerosis, and renal disease of unknown etiology. Most patients had risk factors for or the presence of vascular disease. The mean pre-treatment creatinine was 182 +/- 14 micromol/l (2.1 +/- 0.2 mg/dl) (mean +/- SE), compared to a peak creatinine on the medication of 247 +/- 16 micromol/l (2.8 +/- 0.2 mg/dl) (p < 0.001). The post-medication mean was 183 +/- 13 (2.1 +/- 0.1 mg/dl) (p < 0.001 vs maximum creatinine). Urea values also increased with therapy and decreased following discontinuation of the fibrate. Cyclosporine levels did not change with treatment. All recorded creatine kinase values were within the normal range.
Conclusions: A group of 10 men showed a reversible deterioration in renal function while being treated with a fibrate for hyperlipidemia. The mechanism involved in the deterioration in renal function is not clear. The most plausible mechanism is one based on renal hemodynamics, given the rapid and complete reversibility that was noted and the finding that most patients had risk factors for vascular disease. If patients with pre-existing renal dysfunction are to receive a trial of fibrate therapy, this should be done with caution and