Does metoprolol interact with fish oil supplements?

Metoprolol and fish oil (omega‑3) supplements are generally safe to take together, and a direct, harmful drug–drug interaction is not expected. The most relevant consideration is that fish oil can modestly lower blood pressure on its own, so when combined with a blood pressure medicine like metoprolol (a beta‑blocker), the blood‑pressure‑lowering effect can be slightly additive. This usually isn’t problematic but may contribute to lightheadedness or lower readings in some people, especially at higher omega‑3 doses. ^{[1] [2]}

What “interaction” means here

• Additive blood pressure effect: Fish oil has a small blood‑pressure‑lowering effect; pairing it with metoprolol may increase this effect a little. This is typically mild, but it is worth monitoring if you notice dizziness, faintness, or unusually low readings. ^{[3] [4]}
• Bleeding tendency at high doses: Fish oil can prolong bleeding time, particularly at higher doses, and caution is advised when it’s used with anticoagulants or antiplatelet drugs; metoprolol itself is not a blood thinner, so this point is more relevant if you are also taking agents like aspirin, clopidogrel, or warfarin. ^{[5] [6]}
• No known effect on metoprolol metabolism: There is no established evidence that fish oil changes how metoprolol is processed by the body (for example, via CYP2D6), and official labeling for omega‑3 products does not list metoprolol as a pharmacokinetic interaction. ^{[7] [8]}

What the evidence shows

• Authoritative guidance notes that fish oil may slightly reduce blood pressure, and combining it with blood pressure drugs can increase the overall blood‑pressure‑lowering effect. This is usually small but can be noticeable in some individuals. ^{[1] [2]}
• Prescription omega‑3 products carry cautions about prolonged bleeding time, mainly when combined with blood thinners, not beta‑blockers like metoprolol. Routine co‑use with metoprolol has not been shown to cause clinically significant bleeding problems. ^{[5] [6]}
• Controlled trials of omega‑3 supplementation in people already treated with beta‑blockers or diuretics have shown modest reductions in blood pressure and triglycerides, supporting the concept of an additive but generally gentle effect on blood pressure. This can be beneficial for many, provided blood pressure remains within a healthy range. ^[9]

Practical tips for safe use

• Monitor blood pressure: If you start or increase fish oil while on metoprolol, check your blood pressure at home for a couple of weeks to see how your readings respond. ^{[3] [4]}
• Watch for symptoms: Report persistent dizziness, fatigue, or fainting; these may suggest your blood pressure is dropping more than desired. ^{[3] [2]}
• Discuss bleeding risks if on blood thinners: If you also take anticoagulants or antiplatelet medications, ask your clinician whether your dosage or monitoring needs adjustment when adding fish oil. Metoprolol alone does not raise bleeding risk, but the combination with blood‑thinning therapies may require closer observation. ^{[5] [6]}
• Choose a consistent dose: Typical supplemental doses (for heart health) are often in the range of 1 gram of combined EPA/DHA daily, while prescription omega‑3 doses for triglyceride lowering are higher (around 4 grams/day); higher doses have a greater chance of noticeable blood pressure effects. ^{[1] [10]}
• Quality and timing: If you experience stomach upset, try taking fish oil with meals or consider a different formulation; absorption concerns are more relevant with certain weight‑loss medications (like orlistat), not metoprolol. ^[1]

Bottom line

• No direct harmful interaction is established between metoprolol and fish oil. The main consideration is a small, additive reduction in blood pressure, which many users tolerate well and can even be beneficial. ^{[3] [2]}
• Be mindful of bleeding risk only if you’re on blood thinners or have a bleeding disorder; metoprolol itself isn’t a blood‑thinning medicine. ^{[5] [6]}

Would you like help deciding an appropriate fish oil dose and how to monitor your blood pressure while taking metoprolol?