💊 Fibrates
Drug Class & Overview
Fibrates are a class of lipid-lowering drugs primarily used to reduce elevated triglyceride levels and, to a lesser extent, increase high-density lipoprotein (HDL) cholesterol.
Mechanism of Action
They act as peroxisome proliferator-activated receptor alpha (PPAR-alpha) agonists. This activation leads to increased lipoprotein lipase activity, which enhances the catabolism of triglyceride-rich lipoproteins. Fibrates also decrease hepatic triglyceride synthesis and increase HDL production.
Key Indications
Fibrates are indicated for severe hypertriglyceridaemia, particularly when there is a risk of pancreatitis. They can be used in mixed dyslipidaemia when statins are contraindicated or not tolerated. They may also be considered in patients with type II diabetes and dyslipidaemia.
Contraindications
Absolute contraindications include severe hepatic impairment, severe renal impairment, and pre-existing gallbladder disease. They should also be avoided in patients with a history of photoallergic or phototoxic reactions to fibrates. Concomitant use with statins requires careful consideration due to increased risk of myopathy.
Adverse Effects
Common side effects include gastrointestinal disturbances such as nausea, abdominal pain, and diarrhoea. Myopathy and rhabdomyolysis are serious but rare adverse effects, particularly when co-administered with statins. Liver enzyme elevations and cholelithiasis (gallstones) can also occur.
Monitoring
Liver function tests (LFTs) should be checked before initiating treatment and periodically thereafter. Renal function should also be monitored, especially in elderly patients or those with pre-existing renal impairment. Lipid profiles should be assessed to monitor treatment efficacy.
Prescribing Safety (OSCE)
When prescribing, always check for existing liver or kidney disease and a history of gallbladder issues. Be mindful of concomitant medications, especially statins, and counsel the patient on symptoms of muscle pain or dark urine. Emphasise the importance of regular blood tests.
MLA High-Yield Notes
Fibrates are the go-to for very high triglycerides. Remember the risk of myopathy, especially with statins. The mechanism involves PPAR-alpha activation. Liver and kidney function monitoring is crucial. They are not first-line for primary hypercholesterolaemia.
Common SBA Themes
SBA questions often focus on the primary indication of fibrates (severe hypertriglyceridaemia) and their role when statins are contraindicated. Watch out for scenarios involving elevated LFTs or muscle pain, which could indicate adverse effects. Questions might also explore drug interactions, particularly with statins.
References
- BNF
- NICE Guideline CG181: Cardiovascular disease: risk assessment and reduction, including lipid modification
- MHRA Drug Safety Update