Comparative toxicity and safety profile of fenofibrate and other fibric acid derivatives

Abstract

It is estimated that there are approximately six million patient-years of clinical experience with fenofibrate among physicians outside of the United States. A review of the European literature and unpublished studies supplied by the manufacturer (Laboratoires Fournier, Dijon, France) has been compiled with the data recently reported from a double-blind, placebo-controlled study completed in the United States. In general, fenofibrate has been found to reduce serum triglyceride levels by 30 to 60 percent in patients with type II B and IV hyperlipoproteinemia. Serum cholesterol levels were also reduced by 20 to 25 percent in this group of hypertriglyceridemic patients. A similar reduction in serum cholesterol levels was also found in type II A patients (normal triglyceride levels). Low-density lipoprotein levels were usually reduced in those patients with elevated levels and high-density lipoprotein levels increased when baseline levels were low. Fenofibrate also produced a 10 to 28 percent reduction in uric acid that was sustained for years. The incidence of unwanted effects ranged from 2 to 15 percent in the open trials lasting from a few months up to six years. Gastrointestinal problems (abdominal discomfort, diarrhea, and constipation) are most common, occurring in approximately 5 percent of patients. Reports including fatigue, headache, loss of libido, impotence, dizziness, and insomnia were grouped as neurologic and occurred with a total incidence of 3 to 4 percent. In about 1 percent of patients, muscle tenderness developed, often accompanied by elevated creatine phosphokinase levels. These and the gastrointestinal problems occurred with a similar frequency in the placebo-treated cohort in controlled studies. In approximately 2 percent of patients, a skin rash developed, an incidence that appears significantly higher than that of placebo control groups. Liver changes in rodents have included marked peroxisome proliferation and increased hepatic carcinomas with very high doses. In humans, only a small increase in incidence of elevated levels of serum glutamic oxaloacetic transaminase and serum glutamic pyruvic transaminase seems to be present and is not clearly different from that of the control groups. Alkaline phosphatase, gamma-glutamyl transferase, and bilirubin levels are often decreased with no known undesirable effects. Investigations into the lithogenicity of bile indicated a significant increase in five studies. However, there has been no evidence of a significant rise in the incidence of cholelithasis in the clinical trials completed to date.