Fenofibrate

Fenofibrate (Tricor) is a drug of the fibrate class. It is mainly used to reduce cholesterol levels in patients at risk of cardiovascular disease. Like other fibrates, it reduces both low-density lipoprotein (LDL) and very low density lipoprotein (VLDL) levels, as well as increasing high-density lipoprotein (HDL) levels and reducing triglycerides level. It is used alone or along with statins in the treatment of hypercholesterolemia and hypertriglyceridemia.

Fenofibrate has been used since 1975, is one of the most commonly prescribed fibrates, and has a well known efficacy and tolerability profile.

Medical uses
Fenofibrate is mainly used for primary hypercholesterolemia or mixed dyslipidemia. Fenofibrate appears to decrease the risk of cardiovascular disease and possibly diabetic retinopathy in those with diabetes mellitus. It also appears to be helpful in decreasing amputations of the lower legs in this same group of people.

It is used in addition to diet to reduce elevated low-density lipoprotein cholesterol (LDL), total cholesterol, triglycerides (TG), and apolipoprotein B (Apo B), and to increase high-density lipoprotein cholesterol (HDL) in adults with primary hypercholesterolemia or mixed dyslipidemia. It is used in addition to diet for treatment of adults with severe hypertriglyceridemia. Improving glycemic control in diabetics showing fasting chylomicronemia will usually decrease the need for pharmacologic intervention.
 * Severe hypertriglyceridemia type IV or V

Three randomized, double-blind trials have shown that treatment with fenofibric acid plus a statin improved HDL and triglyceride levels better than a statin alone and improved LDL levels better than fenofibric acid monotherapy.

Additionally, in Europe, fenofibrate is indicated in mixed hyperlipidemia in those with high cardiovascular risk in addition to a statin when triglycerides and HDL are not adequately controlled.

Contraindications
Fenofibrate is contraindicated in:
 * Patients with severe renal impairment, including those receiving dialysis (2.7-fold increase in exposure, and increased accumulation during chronic dosing in patients with estimated glomerular filtration rate (eGFR)<30mL/min)
 * Patients with active liver disease, including those with primary biliary cirrhosis and unexplained persistent liver function test (LFT) abnormalities
 * Patients with preexisting gallbladder disease
 * Nursing mothers
 * Patients with known hypersensitivity to fenofibrate or fenofibric acid

Adverse effects
The most common adverse events (>3% of patients with coadministered statins) are
 * Headache
 * Back pain
 * Nasopharyngitis
 * Nausea
 * Myalgia
 * Diarrhea
 * Upper respiratory tract infection

Precautions
Musculoskeletal Hepatotoxicity Nephrotoxicity Biliary Coagulation/Bleeding
 * Myopathy and rhabdomyolysis; increased risk when coadminstered with a statin, particularly in the elderly and patients with diabetes, renal failure, hypothyroidism
 * Can increase serum transaminases; liver tests should be monitored periodically
 * Can increase serum creatinine levels; renal function should be monitored periodically in patients with renal insufficiency
 * Can increase cholesterol excretion into the bile, leading to risk of cholelithiasis; if suspected gallbladder studies are indicated. Interaction with Bile Acid Sequestrant
 * Exercise caution in concomitant treatment with oral coumarin anticoagulants (e.g. Warfarin). Adjust the dosage of coumarin to maintain the prothrombin time/INR at desired level to prevent bleeding complications

Dosage

 * May be taken without regard to food
 * May be taken at the same time as a statin
 * Coadministration with the maximum dose of a statin should be avoided until studies demonstrate benefit outweighs risk

It is recommended that fenofibrate be given in the morning and the statin at night, "In combined therapy, fibrates should be given in the morning and statins at night so that the peak dosages do not overlap."

Controversy
The pharmaceutical form and the strength may change from one country to another, and from one brand to another. In the United States, Tricor was reformulated in 2005. This reformulation is controversial, as it is seen as an attempt to stifle competition from generic equivalents of the drug, and is the subject of antitrust litigation by generic drug manufacturer Teva. Also available in the United States, Lofibra is available in 54 and 160 mg tablets, as well as 67, 134, and 200;mg micronized capsules. Generic equivalents of Lofibra capsules are currently available in all three strengths in the United States. In Europe, it is available in either coated tablet or capsule; the strength range includes 67, 145, 160 and 200 mg. The differences among strengths are a result of altered bioavailability (the fraction absorbed by the body) due to particle size. For example, 200 mg can be replaced by 160 mg micronized fenofibrate. The 145 mg strength is a new strength that appeared in 2005-2006 which also replaces 200 or 160 mg as the fenofibrate is nanonised (i.e. the particle size is below 400 nm).

Mechanism of action
"In summary, enhanced catabolism of triglyceride-rich particles and reduced secretion of VLDL underlie the hypotriglyceridemic effect of fibrates, whereas their effect on HDL metabolism is associated with changes in HDL apolipoprotein expression."

Fenofibrate is a fibric acid derivative, a prodrug comprising fenofibric acid linked to an isopropyl ester. It lowers lipid levels by activating Peroxisome proliferator-activated receptor alpha (PPARα). PPARα activates lipoprotein lipase and reduces apoprotein CIII, which increases lipolysis and elimination of triglyceride-rich particles from plasma.

PPARα also increases apoproteins AI and AII, reduces very low-density lipoprotein (VLDL) and low-density lipoprotein (LDL) containing apoprotein B, and increases high-density lipoprotein (HDL) containing apoprotein AI and AII.

In addition, by reducing the synthesis and increasing the catabolism of VLDL, fenofibrate increases LDL clearance and reduces small and dense LDL, which are associated with coronary heart disease. Better citation needed

Brand names
Fenofibrate is sold under the brand name Tricor and Trilipix by Abbvie, Lipofen by Kowa Pharmaceuticals America Inc, Lofibra by Teva, Lipanthyl, Lipidil, and Supralip by Abbott Laboratories, Fenocor-67 by Ordain Health Care, Fenogal by SMB Laboratories, Antara by Oscient Pharmaceuticals,Tricheck by Zydus (CND), Atorva TG by Zydus Medica, Golip by GolgiUSA and Storfib by Ranbaxy Laboratories (India).

Once developed by Groupe Fournier SA, it was acquired in 2005 by Solvay Pharmaceutical, a business unit owned by the Belgian corporation, Solvay S.A.. In 2009 Solvay Pharmaceutical was in turn acquired by Abbott Laboratories, which now markets the drug. On Feb 26, 2013, Mylan Pharmaceuticals, a subsidiary of global pharmaceutical company Mylan, launched Fenofibrate Capsules USP.

Research
The underlying mechanism of the ketogenic diet remains unknown, and involvement of PPARα has been suggested. Fenofibrate exhibits anticonvulsant properties comparable to the ketogenic diet in adult rats, using pentylenetetrazol and lithium-pilocarpine models. These findings may be useful for future ketogenic diet study protocols.