Deterioration in renal function associated with fibrate therapy

Background: Fibric acid derivatives (fibrates) are commonly used for the tr eatment of hyperlipidemia. A side-effect of these medications that is not w ell recognized is deterioration in renal function during therapy. This stud y reviewed a series of patients who showed such a deterioration. Methods: T he design was a retrospective chart review. Data extracted included creatin ine, urea, cyclosporine levels, medical history, and medications. Charts we re 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 re nal impairment included diabetes, hypertension, nephrosclerosis, and renal disease of unknown etiology. Most patients had risk factors for or the pres ence of vascular disease. The mean pre-treatment creatinine was 182 +/- 14 mu mol/l (2.1 +/- 0.2 mg/dl) (mean +/- SE), compared to a peak creatinine o n the medication of 247 +/- 16 mu mol/l (2.8 +/- 0.2 mg/dl) (p < 0.001). Th e post-medication mean was 183 +/- 13 (2.1 +/- 0.1 mg/dl) (p < 0. 001 vs ma ximum creatinine). Urea. values also increased with therapy and decreased f ollowing 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 rap id and complete reversibility that was noted and the finding that most pati ents had risk factors for vascular disease. If patients with pre-existing r enal dysfunction are to receive a trial of fibrate therapy. this should be done with caution and regular monitoring of renal function.