Omega-3 and Medicine Interactions: A Reference Table (Blood Pressure Medicines, Orlistat, Anticoagulants and More)
A reference table of what labels, trials and reviews say about omega-3 with blood thinners, blood pressure medicines, orlistat, statins and other medicines, with gaps stated plainly.
Content last updated . This page has not been medically reviewed.
How to use this table
This is a reference, not a list of rules. It records what the sources we read say about omega-3 products and common medicine groups, and where we found nothing. It does not tell you to stop, start or change any medicine. Bring every supplement, including fish oil, krill oil, algal oil and cod liver oil, to your pharmacist or prescriber, who knows your full medicine list. For how interactions work in general, see Medication interactions.Evidence labels: mixed (studies disagree), insufficient (too little good research), label statement (a prescribing-information warning, not proof of cause), preclinical (animal or lab study), Proper evidence not found (we searched and found nothing usable).
Reference table
| Medicine group | What the sources say | Evidence label | Ask about |
|---|---|---|---|
| Anticoagulants (warfarin) | Prescription omega-3 labels say omega-3 acids may prolong bleeding time and advise periodic monitoring. [1] A small trial of 3 to 6 g a day of fish oil found no significant INR change (INR is the clotting test used with warfarin); case reports describe a higher INR in single patients. [2][3] | Mixed | INR monitoring, any change in fish oil |
| Antiplatelets (aspirin, clopidogrel) | In the prescription EPA trial, bleeding was greater in people also taking aspirin, clopidogrel or warfarin. [4] A pooled analysis tied bleeding to EPA dose, not to background antiplatelet use. [5] | Mixed, product-specific | Bleeding signs, surgery plans |
| Blood pressure medicines | A meta-analysis of 36 fish oil trials (median 3.7 g a day) found small drops in blood pressure: 2.1 mmHg systolic and 1.6 mmHg diastolic, larger in hypertensive people. [6] That analysis excluded trials with co-interventions, so it does not show what happens alongside blood pressure medicines. Proper evidence not found: our PubMed searches for omega-3 with antihypertensive drugs returned no trial testing the combination. | Insufficient | Home blood pressure readings, dizziness |
| Orlistat (fat-absorption blocker) | The orlistat label says it can reduce absorption of some vitamins. [7] In rats given fish oil, a high orlistat level cut EPA incorporation into red blood cells by 45%. [8] Proper evidence not found in humans: our PubMed search found no human study of orlistat with omega-3 supplements. | Preclinical only | What the orlistat label says about vitamins |
| Cholesterol and triglyceride medicines (statins) | A systematic review found low-strength evidence of added triglyceride lowering when omega-3 was added to statins, and said safety concerns persist. [9] The prescription omega-3 label says LDL cholesterol can rise and should be monitored. [1] | Label statement; low strength | Lipid tests |
| Diabetes medicines | FDA's 2019 review found EPA and DHA intake up to 10 g a day appears to have no adverse effect on fasting glucose or HbA1c. [10] No study of omega-3 with specific diabetes medicines was found in the sources we read. | Insufficient for interactions | Glucose monitoring |
| Vitamin A from cod liver oil | The NHS says fish liver oil is high in vitamin A, and advises that vitamin A from food and supplements combined should not exceed 1.5 mg a day (UK advice, adults). [11] | Official advice | Other vitamin A sources |
| Other medicines (anti-seizure, thyroid, transplant, cancer treatment, antidepressants) | Not described in the sources we read. | Proper evidence not found | Pharmacist review |
What the table cannot tell you
- Product matters. Rows that cite prescription labels describe prescription products. NCCIH says their composition, testing and regulation differ from supplements, so effects may not be the same. [12]
- Study amounts are not advice. Trial amounts are shown only to say what was tested.
- Absence is not safety. "Not described in the sources we read" means we have no information, not that a combination is safe.
- Flaxseed oil is different. It supplies ALA, not EPA and DHA; see ALA, EPA and DHA.
Who should check first
People taking several medicines, older adults, people with a bleeding disorder, kidney or liver disease, or surgery planned should ask a pharmacist before adding any omega-3 product. For the bleeding detail, see fish oil, blood thinners and bleeding risk. For product quality, see Quality testing and certifications.Frequently asked questions
Does fish oil interact with blood pressure medicine?
Fish oil trials found small average blood pressure drops, but we found no trial that tested fish oil together with blood pressure medicines. Ask your pharmacist. [6]
Does fish oil interact with statins?
A systematic review found low-strength evidence of extra triglyceride lowering when omega-3 was added to statins, and the prescription omega-3 label advises monitoring LDL cholesterol. Your prescriber decides what suits you. [9][1]
Does orlistat affect omega-3 absorption?
Orlistat blocks some fat absorption and reduced EPA incorporation in rats fed fish oil. We found no human study. Ask your pharmacist. [8][7]
Does cod liver oil add to other vitamin A sources?
It is high in vitamin A, so it counts toward the total from food and other supplements; the NHS gives a UK adult limit of 1.5 mg a day from all sources combined. [11]
Is every omega-3 and medicine combination listed here?
No. The table covers only what the sources we read describe. For anything not listed, ask a pharmacist or clinician.
References
- FDA prescribing information for omega-3-acid ethyl esters capsules, via openFDA drug label API (label effective 2023-10-06). Read 2026-10-23.
- Bender NK et al., Effects of Marine Fish Oils on the Anticoagulation Status of Patients Receiving Chronic Warfarin Therapy. J Thromb Thrombolysis 1998. Read 2026-10-23.
- Buckley MS et al., Fish oil interaction with warfarin. Ann Pharmacother 2004 (case report). Read 2026-10-23.
- FDA prescribing information for icosapent ethyl capsules, via openFDA drug label API (label effective 2026-03-23). Read 2026-10-23.
- Javaid M et al., Bleeding Risk in Patients Receiving Omega-3 Polyunsaturated Fatty Acids: A Systematic Review and Meta-Analysis of Randomized Clinical Trials. J Am Heart Assoc 2024. Read 2026-10-23.
- Geleijnse JM et al., Blood pressure response to fish oil supplementation: metaregression analysis of randomized trials. J Hypertens 2002. Read 2026-10-23.
- FDA label for over-the-counter orlistat capsules, via openFDA drug label API (label effective 2024-03-27). Read 2026-10-23.
- Cruz-Hernandez C et al., Lipase inhibitor orlistat decreases incorporation of eicosapentaenoic and docosahexaenoic acids in rat tissues. Nutr Res 2010. Read 2026-10-23.
- Kanji S et al., Interactions of commonly used dietary supplements with cardiovascular drugs: a systematic review. Syst Rev 2012. Read 2026-10-23.
- FDA, Letter on the qualified health claim petition for EPA and DHA and reduction of blood pressure (Docket FDA-2014-Q-1146), 19 June 2019. Read 2026-10-23.
- NHS, Vitamin A (page last reviewed 3 August 2020). Read 2026-10-23.
- NCCIH, Omega-3 Supplements: What You Need To Know. Read 2026-10-23.
Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.