Furosemide Clofibrate

Treatment with clofibrate in patients with nephrotic syndrome receiving furosemide has sometimes led to marked diuresis and severe and disabling adverse muscular effects. An isolated report describes rhabdomyolysis in a patient taking bezafibrate and furosemide. 

Three patients with hyperlipoproteinaemia secondary to nephrotic syndrome, taking furosemide 80 to 500 mg daily, developed severe muscle pain, low lumbar baekaehe, stiffness, and general malaise with pronounced diuresis within 3 days of starting to take clofibrate 1 to 2 g daily. Similarly, a patient taking bendrofiumethiazide 10 mg daily developed adverse musele effeets within 3 days of starting clofibrate. Of these 4 patients, 3 had doeumented raised serum transaminases or creatine phos-phokinase. 

Not understood. The marked diuresis may have been due to eompetition and displaeement of the furosemide by the elofibrate from its plasma protein binding sites. Clofibrate oeeasionally eauses a musele toxieity, which could have been exacerbated by the urinary loss of Na and K and the increase in the half-life of clofibrate. The reason for the bezafibrate/furo-semide-induced rhabdomyolysis is unknown. 

The clinical documentation seems to be limited to these reports. It appears to be a combination of a drug-drug interaction (clofibrate with furosemide) with or without a drug-disease interaction (clofibrate with nephrotic syndrome). The authors of one report suggest that serum proteins and renal function should be checked before giving clofibrate to any patient. If serum albumin is low, the total daily dosage of clofibrate should not exceed 500 mg for each 1 g per 100 mL of the albumin concentration. However, note that this guidance is old. 

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