Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
OMACOR vs FENOFIBRIC ACID
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Omega-3-acid ethyl esters (EPA and DHA) reduce hepatic triglyceride synthesis by inhibiting acyl-Co A:1,2-diacylglycerol acyltransferase and increasing beta-oxidation. They also decrease very-low-density lipoprotein (VLDL) secretion and enhance triglyceride clearance from circulating VLDL particles.
Fenofibric acid is a peroxisome proliferator-activated receptor alpha (PPARα) agonist that increases lipolysis and clearance of triglyceride-rich lipoproteins and reduces apolipoprotein C-III production, leading to decreased triglycerides and increased HDL cholesterol.
FDA: Adjunct to diet for reduction of triglyceride levels in adult patients with severe hypertriglyceridemia (≥500 mg/d L).,Off-label: Secondary prevention of cardiovascular events in patients with hypertriglyceridemia or high cardiovascular risk.
Adjunct to diet for treatment of severe hypertriglyceridemia (Fredrickson types IV and V hyperlipidemia),Adjunct to diet for reduction of LDL-C, total-C, triglycerides, and Apo B in primary hypercholesterolemia or mixed dyslipidemia (Fredrickson types IIa and IIb)
4 g orally once daily or 2 g orally twice daily, taken with meals. Each capsule contains 1 g of omega-3-acid ethyl esters (approximately 465 mg eicosapentaenoic acid and 375 mg docosahexaenoic acid).
135 mg orally once daily
Terminal elimination half-life: ~55–75 hours for EPA and DHA (beta-phase). Clinical context: steady-state achieved after 4–8 weeks; half-life supports once-daily dosing.
Terminal elimination half-life is approximately 20 hours (range 15-25 h) for fenofibric acid, supporting once-daily dosing. In renal impairment, half-life may be prolonged.
Omega-3-acid ethyl esters are primarily hydrolyzed by pancreatic lipase to free fatty acids (EPA and DHA), which are then absorbed and incorporated into chylomicrons. They undergo hepatic metabolism via beta-oxidation. CYP450 involvement is minimal.
Primarily hepatic via glucuronidation; minor CYP3A4 involvement. Excreted as glucuronide conjugates in urine and feces.
Primarily fecal as unchanged drug and metabolites; <5% renal. Biliary excretion accounts for ~90% of elimination via feces, with minimal urinary excretion (0.5–2%).
Primarily renal as unchanged drug and glucuronide conjugate (approximately 60-70% of dose); remainder eliminated via biliary/fecal routes (~25%).
Highly protein-bound (>99%) primarily to albumin.
Highly bound to serum albumin (approximately 99%).
Vd: ~0.2–0.3 L/kg (EPA), ~2–3 L/kg (DHA). Clinical meaning: extensive tissue distribution, especially in adipose and cardiac tissues.
Approximately 0.4 L/kg (range 0.2-0.6 L/kg), indicating distribution mainly in extracellular fluid.
Oral: 50–100% (enhanced with fatty meal; absolute bioavailability not determined).
Oral bioavailability of fenofibric acid is approximately 100% when administered as the choline salt; the capsule formulation has high bioavailability relative to tablet. Food may reduce rate but not extent of absorption.
No dose adjustment required for any degree of renal impairment. Use caution in patients with renal disease due to potential for increased bleeding risk.
If e GFR 30-59 m L/min: reduce dose to 45 mg orally once daily. If e GFR <30 m L/min: contraindicated.
Contraindicated in patients with Child-Pugh class C (severe) hepatic impairment. For Child-Pugh A or B, no dose adjustment is recommended, but monitor liver function tests periodically.
Contraindicated in Child-Pugh class B or C; no dose adjustment defined for Child-Pugh A (use with caution).
Safety and efficacy not established in pediatric patients. Not recommended for use in children.
Not approved for use in pediatric patients.
No specific dose adjustment recommended. Monitor for potential drug interactions, especially with anticoagulants, due to increased bleeding risk. Start at lower end of dosing range if elderly patient has significant comorbidity or polypharmacy.
No specific dose adjustment required; consider renal function and potential for decreased renal clearance in elderly.
No FDA black box warning.
None
Increased bleeding risk (monitor patients on anticoagulants).,Atrial fibrillation in patients with prior history or at high risk.,Persistent elevations of ALT or AST, especially with other hepatotoxic drugs.,Hypersensitivity reactions including anaphylaxis.,Fish allergy (capsules contain fish oil).
Hepatotoxicity: elevation of serum transaminases; contraindicated in active liver disease.,Myopathy/rhabdomyolysis risk, especially with statins or in patients with renal impairment, hypothyroidism, or alcohol abuse.,Cholelithiasis: risk of gallstones due to increased cholesterol excretion into bile.,Pancreatitis: reported in hypertriglyceridemia patients.,Renal impairment: dose adjustment required; avoid in severe renal disease.,Venothromboembolic events: increased risk in clinical trials.
Hypersensitivity to omega-3-acid ethyl esters or any component.,Acute pancreatitis with marked hypertriglyceridemia (consider if triglycerides >500 mg/d L and chylomicronemia).
Active liver disease including primary biliary cirrhosis and unexplained persistent liver function abnormalities.,Known gallbladder disease (cholelithiasis).,Severe renal impairment (e GFR <30 m L/min/1.73 m²).,Hypersensitivity to fenofibrate or fenofibric acid.
Avoid high-fat meals as they may increase triglyceride levels. No specific food interactions known, but consistency in timing with meals is recommended.
Take with food to enhance absorption and reduce gastrointestinal intolerance. Avoid high-fat meals as they may exacerbate hypertriglyceridemia and reduce drug efficacy.
FDA Pregnancy Category C. No evidence of teratogenicity in animal studies at doses up to 10 times the human dose. There are no adequate and well-controlled studies in pregnant women. Use only if potential benefit justifies potential risk to fetus. Omega-3-acid ethyl esters may inhibit prostaglandin synthesis and delay labor. Third trimester use may increase risk of bleeding in mother and neonate.
Pregnancy Category C. First trimester: Data insufficient to assess risk; animal studies show embryotoxicity and teratogenicity at high doses. Second/third trimesters: Avoid use due to potential fetal harm; no well-controlled human studies.
Not recommended during breastfeeding. Omega-3 fatty acids are excreted in human milk; M/P ratio not established. Potential for adverse effects in nursing infant. Consider alternative treatment or discontinue nursing.
Excreted in breast milk in rats; human data unknown. Use caution, especially in preterm or jaundiced infants. M/P ratio not established.
No specific dose adjustments recommended for pregnancy-induced pharmacokinetic changes. Use with caution as pregnancy may alter lipid profiles; monitor triglyceride levels and adjust dose accordingly.
Avoid use during pregnancy; no established safe dose. Pharmacokinetic changes (increased volume of distribution, clearance) may reduce efficacy; dose adjustments not recommended due to potential fetal risk.
Omacor (omega-3-acid ethyl esters) is indicated as an adjunct to diet for severe hypertriglyceridemia (≥500 mg/d L). Monitor LDL-C levels as they may increase during therapy; adjust statin dose if needed. Administer with meals to enhance absorption and reduce gastrointestinal side effects. Avoid use in patients with fish or shellfish allergy. May prolong bleeding time; monitor in patients on anticoagulants.
Fenofibric acid is a PPARα agonist that reduces triglycerides by 30-50% and increases HDL; monitor renal function as dose adjustment required for Cr Cl 30-59 m L/min; contraindicated in severe renal impairment (Cr Cl <30 m L/min) and active liver disease; may increase serum creatinine; use with caution in patients with gallbladder disease; can potentiate warfarin effect (monitor INR).
Take with food to improve absorption and reduce burping or fishy taste.,Do not take if you have an allergy to fish or shellfish.,Report unusual bleeding or bruising, especially if you are on blood thinners.,Do not substitute with over-the-counter fish oil supplements as they are not equivalent.,Continue dietary modifications and exercise as part of your treatment plan.
Take with food to reduce GI side effects.,Report unexplained muscle pain, tenderness, or weakness, especially if accompanied by fever or malaise.,Avoid alcohol as it can increase triglyceride levels and worsen liver effects.,This medication is not a substitute for diet and exercise; continue lifestyle modifications.,Notify your doctor if you develop abdominal pain (possible gallstones).
No interactions on record
"Fenofibric acid, a peroxisome proliferator-activated receptor alpha (PPARα) agonist, may reduce the therapeutic efficacy of ursodeoxycholic acid (UDCA) by increasing the biliary excretion of cholesterol and altering bile acid composition, thereby counteracting the beneficial effects of UDCA in dissolving cholesterol gallstones and improving cholestatic liver diseases. This interaction can lead to reduced clinical response, including incomplete stone dissolution or worsening of liver function tests in conditions such as primary biliary cholangitis."
"Glisoxepide may increase the hypoglycemic activities of Fenofibric acid."
"Colchicine may increase the myopathic rhabdomyolysis activities of Fenofibric acid."
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about OMACOR vs FENOFIBRIC ACID, answered by our medical review team.
OMACOR is a Antilipemic that works by Omega-3-acid ethyl esters (EPA and DHA) reduce hepatic triglyceride synthesis by inhibiting acyl-Co A:1,2-diacylglycerol acyltransferase and increasing beta-oxidation. They also decrease very-low-density lipoprotein (VLDL) secretion and enhance triglyceride clearance from circulating VLDL particles.. FENOFIBRIC ACID is a Antilipemic that works by Fenofibric acid is a peroxisome proliferator-activated receptor alpha (PPARα) agonist that increases lipolysis and clearance of triglyceride-rich lipoproteins and reduces apolipoprotein C-III production, leading to decreased triglycerides and increased HDL cholesterol.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between OMACOR and FENOFIBRIC ACID depend on the specific clinical indication. These are both Antilipemic agents and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of OMACOR is: 4 g orally once daily or 2 g orally twice daily, taken with meals. Each capsule contains 1 g of omega-3-acid ethyl esters (approximately 465 mg eicosapentaenoic acid and 375 mg docosahexaenoic acid).. The standard adult dose of FENOFIBRIC ACID is: 135 mg orally once daily. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.
No direct drug-drug interaction has been formally documented between OMACOR and FENOFIBRIC ACID in current clinical databases. However, individual patient risk factors including other medications, organ function, and comorbidities should always be evaluated by a qualified healthcare provider.
The maternal-fetal safety profiles differ. OMACOR is classified as Category C. FDA Pregnancy Category C. No evidence of teratogenicity in animal studies at doses up to 10 times the human dose. There are no adequate and well-controlled studies in pregnant wome. FENOFIBRIC ACID is classified as Category C. Pregnancy Category C. First trimester: Data insufficient to assess risk; animal studies show embryotoxicity and teratogenicity at high doses. Second/third trimesters: Avoid use due. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.