Hyperlipidaemias Quiz

See Fibrates. Option B is correct because fibrates such as fenofibrate and bezafibrate activate PPAR-alpha (peroxisome proliferator-activated receptor alpha), a nuclear transcription factor, meaning a protein inside the cell that switches genes on. Activating it increases the production of lipoprotein lipase, the enzyme on the walls of blood vessels that breaks down triglycerides in lipoproteins, and increases uptake of fatty acids in the liver. The main result is a fall in triglycerides of about 30 to 50 per cent, with HDL often rising. The LDL response depends on the lipid pattern, and LDL can even rise in some patients with high triglycerides. The BNF states that fibrates act by decreasing serum triglycerides and have a variable effect on LDL cholesterol. They are mainly used for severe hypertriglyceridaemia, where the risk of acute pancreatitis is high, and are usually started by a specialist. Combination with a statin raises the risk of muscle damage (rhabdomyolysis), and gemfibrozil with a statin is contraindicated. A simple memory aid is that fibrates are for fats in the form of triglycerides, statins are for LDL.

• Target: PPAR-alpha, a nuclear transcription factor.
• Action: more lipoprotein lipase, the enzyme that breaks down triglycerides in lipoproteins.
• Main effect: triglycerides fall by about 30 to 50 per cent, with a variable effect on LDL.

Fibrates act through a nuclear receptor and mainly lower triglycerides, which separates them from the other four.