Skip to main content

Icosapent Side Effects

Medically reviewed by Philip Thornton, DipPharm. Last updated on May 30, 2023.

Applies to icosapent: oral capsule liquid filled.

Serious side effects of Icosapent

Along with its needed effects, icosapent may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking icosapent:

Less common

Other side effects of Icosapent

Some side effects of icosapent may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Less common

Incidence not known

For Healthcare Professionals

Applies to icosapent: oral capsule.


The more commonly reported adverse reactions in the cardiovascular outcome trial included bleeding, musculoskeletal pain, peripheral edema, constipation, gout, rash, and atrial fibrillation. The more commonly reported adverse reactions in the hypertriglyceridemia trials included arthralgia and oropharyngeal pain.[Ref]


During a clinical trial in statin-treated patients with established cardiovascular disease (CVD) or diabetes plus an additional risk factor for CVD, atrial fibrillation or atrial flutter occurred in 5.8% of patients receiving this drug compared with 4.5% of placebo-treated patients; adjudicated atrial fibrillation or atrial flutter requiring hospitalization for at least 24 hours occurred in 3% of patients receiving this drug compared with 2% of placebo-treated patients. Atrial fibrillation and atrial flutter were reported more often in patients with history of atrial fibrillation or atrial flutter receiving this drug than in those receiving placebo (12.5% vs 6.3%).

Common (1% to 10%): Atrial fibrillation/flutter


Common (1% to 10%): Rash, contusion


In a cardiovascular outcomes trial, constipation was reported in 5.4% of patients receiving this drug compared with 3.6% of placebo-treated patients; serious constipation was less common for this drug (0.1%) and placebo (0.2%). The relative incidence of constipation in this study may have been confounded by a residual laxative effect for placebo, which comprised a subtherapeutic dose of light mineral oil (4 mL).

Common (1% to 10%): Constipation, eructation, gastrointestinal bleeding

Postmarketing reports: Diarrhea, abdominal discomfort


Common (1% to 10%): Hematuria


During clinical trials in patients with established CVD or diabetes plus an additional risk factor for CVD, a bleeding event occurred in 11.8% of patients receiving this drug compared to 9.9% of placebo-treated patients. Serious bleeding events occurred in 3.4% of patients receiving this drug compared to 2.6% of placebo-treated patients when coadministered with an antithrombotic agent, but were reported at a similar rate (0.2%) in patients not taking a concurrent anticoagulant/antiplatelet agent.

The bleeding events reported most often were gastrointestinal bleeding (3.1%), contusion (2.5%), hematuria (1.9%), and epistaxis (1.5%).

Some published studies with omega-3 fatty acids have demonstrated prolongation of bleeding time. The prolongation of bleeding time reported in those studies did not exceed normal limits and did not produce clinically significant bleeding episodes.

Very Common (10% or greater): Bleeding event (up to 12%)

Common (1% to 10%): Serious bleeding event

Frequency not reported: Prolonged bleeding time


Uncommon (0.1% to 1%): Hypersensitivity


Common (1% to 10%): Gout


Common (1% to 10%): Arthralgia, musculoskeletal pain

Postmarketing reports: Pain in the extremities

Nervous system

Uncommon (0.1% to 1%): Dysgeusia (i.e., fishy taste)


Common (1% to 10%): Peripheral edema

Postmarketing reports: Increased blood triglycerides


Common (1% to 10%): Oropharyngeal pain, epistaxis

Frequency not reported: Pharyngeal swelling

Frequently asked questions


1. Product Information. Vascepa (icosapent). Amarin Pharmaceuticals Inc. 2019;SUPPL-35.

2. Product Information. Vazkepa (icosapent). Amarin Pharmaceuticals Ireland Ltd. 2022.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.